diff --git a/Setup.hs b/Setup.hs
--- a/Setup.hs
+++ b/Setup.hs
@@ -1,2 +1,4 @@
+#! /usr/bin/env nix-shell
+#! nix-shell ./shell.nix -i runghc
 import Distribution.Simple
 main = defaultMain
diff --git a/changelog.md b/changelog.md
--- a/changelog.md
+++ b/changelog.md
@@ -1,3 +1,24 @@
+# Version 0.3
+
+* BREAKING CHANGE: The `Data.Money` module was renamed to `Money`.
+
+* BREAKING CHANGE: The `Data.Money.Internal` module is not exposed anymore. All
+  of its contents are now exported from the `Money` module.
+
+* BREAKING CHANGE: Renamed `discreteRep` to `toDiscreteRep`.
+
+* BREAKING CHANGE: Renamed `denseRep` to `toDenseRep`.
+
+* BREAKING CHANGE: Renamed `exchangeRateRep` to `toExchangeRateRep`.
+
+* BREAKING CHANGE: Renamed Iceleandic currency `"eyir"` to `"eyrir"`
+
+* Remove upper bound constraints from all dependencies except `base`.
+
+* Made dependency on `store` optional for the test suite, so that it can run on
+  GHCJS.
+
+
 # Version 0.2
 
 * Cabal flags are now manual (`aeson`, `binary`, `bytes`, `cereal`, `deepseq`,
diff --git a/safe-money.cabal b/safe-money.cabal
--- a/safe-money.cabal
+++ b/safe-money.cabal
@@ -1,8 +1,8 @@
 name: safe-money
-version: 0.2
+version: 0.3
 license: BSD3
 license-file: LICENSE
-copyright: Copyright (c) Renzo Carbonara 2016
+copyright: Copyright (c) Renzo Carbonara 2016-2017
 author: Renzo Carbonara
 maintainer: renλren!zone
 stability: Experimental
@@ -13,8 +13,17 @@
 build-type: Simple
 cabal-version: >=1.10
 extra-source-files: README.md changelog.md
-synopsis: Type-safe and lossless encoding and manipulation of money, world currencies and precious metals.
-description: Type-safe and lossless encoding and manipulation of money, world currencies and precious metals.
+synopsis:
+  Type-safe and lossless encoding and manipulation of money, fiat currencies,
+  crypto currencies and precious metals.
+description:
+  Type-safe and lossless encoding and manipulation of money, fiat currencies,
+  crypto currencies and precious metals.
+  .
+  Notice that the only mandatory dependencies of this package are @base@ and
+  @constraints@. The rest of the dependencies are optional but enabled by
+  default (except @store@ which is also disabled when building with GHCJS), they
+  can be disabled with Cabal flags.
 
 source-repository head
   type: git
@@ -24,44 +33,43 @@
   default-language: Haskell2010
   hs-source-dirs: src
   ghc-options: -Wall -O2
-  exposed-modules:
-      Data.Money
-      Data.Money.Internal
-  build-depends:
-      base (>=4.8 && <5.0)
-    , constraints (>=0.6 && <0.9)
+  exposed-modules: Money
+  other-modules: Money.Internal
+  build-depends: base (>=4.8 && <5.0), constraints
 
   if flag(aeson)
-    build-depends: aeson (>=0.9 && <1.1)
+    build-depends: aeson (>=0.9)
   if flag(binary)
-    build-depends: binary (>=0.7 && <0.9)
+    build-depends: binary (>=0.7)
   if flag(cereal)
-    build-depends: cereal (>=0.5 && <0.6)
+    build-depends: cereal (>=0.5)
   if flag(deepseq)
-    build-depends: deepseq (>=1.4 && <1.5)
+    build-depends: deepseq (>=1.4)
   if flag(hashable)
-    build-depends: hashable (>=1.2 && <1.3)
-  if flag(store)
-    build-depends: store (>=0.2 && <0.4)
+    build-depends: hashable (>=1.2)
+  if (flag(store) && !impl(ghcjs))
+    build-depends: store (>=0.2)
 
-test-suite tests
+test-suite test
   default-language: Haskell2010
   type: exitcode-stdio-1.0
-  hs-source-dirs: tests src
+  hs-source-dirs: test
   main-is: Main.hs
   build-depends:
-     aeson
-   , base
-   , binary
-   , bytestring
-   , cereal
-   , constraints
-   , deepseq
-   , hashable
-   , store
-   , tasty
-   , tasty-hunit
-   , tasty-quickcheck
+    aeson,
+    base,
+    binary,
+    bytestring,
+    cereal,
+    constraints,
+    deepseq,
+    hashable,
+    safe-money,
+    tasty,
+    tasty-hunit,
+    tasty-quickcheck
+  if (flag(store) || !impl(ghcjs))
+    build-depends: store
 
 flag aeson
   description: Provide instances for @aeson@
diff --git a/src/Data/Money.hs b/src/Data/Money.hs
deleted file mode 100644
--- a/src/Data/Money.hs
+++ /dev/null
@@ -1,770 +0,0 @@
-{-# LANGUAGE CPP #-}
-{-# LANGUAGE DataKinds #-}
-{-# LANGUAGE TypeFamilies #-}
-{-# LANGUAGE UndecidableInstances #-}
-
--- | Import this module qualified:
---
--- @
--- import qualified Data.Money as Money
--- @
-module Data.Money
- ( -- * Dense monetary values
-   I.Dense
- , I.dense
-   -- * Discrete monetary values
- , I.Discrete
- , I.Discrete'
- , I.fromDiscrete
- , I.round
- , I.ceiling
- , I.floor
- , I.truncate
-   -- * Currency scales
- , I.Scale
- , I.GoodScale
- , I.scale
-   -- * Currency exchange
- , I.ExchangeRate
- , I.exchangeRate
- , I.fromExchangeRate
- , I.flipExchangeRate
- , I.exchange
-   -- * Serializable representations
- , I.DenseRep
- , I.denseRep
- , I.fromDenseRep
- , I.withDenseRep
- , I.DiscreteRep
- , I.discreteRep
- , I.fromDiscreteRep
- , I.withDiscreteRep
- , I.ExchangeRateRep
- , I.exchangeRateRep
- , I.fromExchangeRateRep
- , I.withExchangeRateRep
- ) where
-
-import qualified Data.Money.Internal as I
-
---------------------------------------------------------------------------------
--- Currency scales
-
--- | United Arab Emirates dirham
-type instance I.Scale "AED" "AED" = '(100, 1)
-type instance I.Scale "AED" "dirham" = '(1, 1)
-type instance I.Scale "AED" "fils" = '(100, 1)
--- | Afghan afghani
-type instance I.Scale "AFN" "AFN" = '(100, 1)
-type instance I.Scale "AFN" "afghani" = '(1, 1)
-type instance I.Scale "AFN" "pul" = '(100, 1)
--- | Albanian lek
-type instance I.Scale "ALL" "ALL" = '(100, 1)
-type instance I.Scale "ALL" "lek" = '(1, 1)
-type instance I.Scale "ALL" "qindarke" = '(100, 1)
--- | Armenian dram
-type instance I.Scale "AMD" "AMD" = '(100, 1)
-type instance I.Scale "AMD" "dram" = '(1, 1)
-type instance I.Scale "AMD" "luma" = '(100, 1)
--- | Netherlands Antillean guilder
-type instance I.Scale "ANG" "ANG" = '(100, 1)
-type instance I.Scale "ANG" "guilder" = '(1, 1)
-type instance I.Scale "ANG" "cent" = '(100, 1)
--- | Angolan kwanza
-type instance I.Scale "AOA" "AOA" = '(100, 1)
-type instance I.Scale "AOA" "kwanza" = '(1, 1)
-type instance I.Scale "AOA" "centimo" = '(100, 1)
--- | Argentine peso
-type instance I.Scale "ARS" "ARS" = '(100, 1)
-type instance I.Scale "ARS" "peso" = '(1, 1)
-type instance I.Scale "ARS" "centavo" = '(100, 1)
--- | Australian dollar
-type instance I.Scale "AUD" "AUD" = '(100, 1)
-type instance I.Scale "AUD" "dollar" = '(1, 1)
-type instance I.Scale "AUD" "cent" = '(100, 1)
--- | Aruban florin
-type instance I.Scale "AWG" "AWG" = '(100, 1)
-type instance I.Scale "AWG" "florin" = '(1, 1)
-type instance I.Scale "AWG" "cent" = '(100, 1)
--- | Azerbaijani manat
-type instance I.Scale "AZN" "AZN" = '(100, 1)
-type instance I.Scale "AZN" "manat" = '(1, 1)
-type instance I.Scale "AZN" "qapik" = '(100, 1)
--- | Bosnia and Herzegovina convertible mark
-type instance I.Scale "BAM" "BAM" = '(100, 1)
-type instance I.Scale "BAM" "mark" = '(1, 1)
-type instance I.Scale "BAM" "fening" = '(100, 1)
--- | Barbadian dollar
-type instance I.Scale "BBD" "BBD" = '(100, 1)
-type instance I.Scale "BBD" "dollar" = '(1, 1)
-type instance I.Scale "BBD" "cent" = '(100, 1)
--- | Bangladeshi taka
-type instance I.Scale "BDT" "BDT" = '(100, 1)
-type instance I.Scale "BDT" "taka" = '(1, 1)
-type instance I.Scale "BDT" "paisa" = '(100, 1)
--- | Bulgarian lev
-type instance I.Scale "BGN" "BGN" = '(100, 1)
-type instance I.Scale "BGN" "lev" = '(1, 1)
-type instance I.Scale "BGN" "stotinka" = '(100, 1)
--- | Bahraini dinar
-type instance I.Scale "BHD" "BHD" = '(1000, 1)
-type instance I.Scale "BHD" "dinar" = '(1, 1)
-type instance I.Scale "BHD" "fils" = '(1000, 1)
--- | Burundi franc
-type instance I.Scale "BIF" "BIF" = '(100, 1)
-type instance I.Scale "BIF" "franc" = '(1, 1)
-type instance I.Scale "BIF" "centime" = '(100, 1)
--- | Bermudian dollar
-type instance I.Scale "BMD" "BMD" = '(100, 1)
-type instance I.Scale "BMD" "dollar" = '(1, 1)
-type instance I.Scale "BMD" "cent" = '(100, 1)
--- | Brunei dollar
-type instance I.Scale "BND" "BND" = '(100, 1)
-type instance I.Scale "BND" "dollar" = '(1, 1)
-type instance I.Scale "BND" "sen" = '(100, 1)
--- | Bolivian boliviano
-type instance I.Scale "BOB" "BOB" = '(100, 1)
-type instance I.Scale "BOB" "boliviano" = '(1, 1)
-type instance I.Scale "BOB" "centavo" = '(100, 1)
--- | Bolivian Mvdol
-type instance I.Scale "BOV" "BOV" = '(100, 1)
--- | Brazilian real
-type instance I.Scale "BRL" "BRL" = '(100, 1)
-type instance I.Scale "BRL" "real" = '(1, 1)
-type instance I.Scale "BRL" "centavo" = '(100, 1)
--- | Bahamian dollar
-type instance I.Scale "BSD" "BSD" = '(100, 1)
-type instance I.Scale "BSD" "dollar" = '(1, 1)
-type instance I.Scale "BSD" "cent" = '(1, 1)
--- | Bhutanese ngultrum
-type instance I.Scale "BTN" "BTN" = '(100, 1)
-type instance I.Scale "BTN" "ngultrum" = '(1, 1)
-type instance I.Scale "BTN" "chetrum" = '(100, 1)
--- | Botswana pula
-type instance I.Scale "BWP" "BWP" = '(100, 1)
-type instance I.Scale "BWP" "pula" = '(1, 1)
-type instance I.Scale "BWP" "thebe" = '(100, 1)
--- | Belarusian ruble
-type instance I.Scale "BYN" "BYN" = '(100, 1)
--- | Belarusian ruble
-type instance I.Scale "BYR" "BYR" = '(100, 1)
-type instance I.Scale "BYR" "ruble" = '(1, 1)
-type instance I.Scale "BYR" "kapyeyka" = '(100, 1)
--- | Belize dollar
-type instance I.Scale "BZD" "BZD" = '(100, 1)
-type instance I.Scale "BZD" "dollar" = '(1, 1)
-type instance I.Scale "BZD" "cent" = '(100, 1)
--- | Canadian dollar
-type instance I.Scale "CAD" "CAD" = '(100, 1)
-type instance I.Scale "CAD" "dollar" = '(1, 1)
-type instance I.Scale "CAD" "cent" = '(100, 1)
--- | Congolese franc
-type instance I.Scale "CDF" "CDF" = '(100, 1)
-type instance I.Scale "CDF" "franc" = '(1, 1)
-type instance I.Scale "CDF" "centime" = '(100, 1)
--- | WIR euro
-type instance I.Scale "CHE" "CHE" = '(100, 1)
--- | Swiss franc
-type instance I.Scale "CHF" "CHF" = '(100, 1)
-type instance I.Scale "CHF" "franc" = '(1, 1)
-type instance I.Scale "CHF" "rappen" = '(100, 1)
--- | WIR franc
-type instance I.Scale "CHW" "CHW" = '(100, 1)
--- | Chilean unidad de fomento
-type instance I.Scale "CLF" "CLF" = '(100, 1)
--- | Chilean peso
-type instance I.Scale "CLP" "CLP" = '(100, 1)
-type instance I.Scale "CLP" "peso" = '(1, 1)
-type instance I.Scale "CLP" "centavo" = '(100, 1)
--- | Chinese Renminbi
-type instance I.Scale "CNY" "CNY" = '(100, 1)
-type instance I.Scale "CNY" "yuan" = '(1, 1)
-type instance I.Scale "CNY" "fen" = '(100, 1)
--- | Colombian peso
-type instance I.Scale "COP" "COP" = '(100, 1)
-type instance I.Scale "COP" "peso" = '(1, 1)
-type instance I.Scale "COP" "centavo" = '(100, 1)
--- | Colombian unidad de valor real
-type instance I.Scale "COU" "COU" = '(100, 1)
--- | Costa Rican colon
-type instance I.Scale "CRC" "CRC" = '(100, 1)
-type instance I.Scale "CRC" "colon" = '(1, 1)
-type instance I.Scale "CRC" "centimo" = '(100, 1)
--- | Cuban peso convertible
-type instance I.Scale "CUC" "CUC" = '(100, 1)
-type instance I.Scale "CUC" "peso" = '(1, 1)
-type instance I.Scale "CUC" "centavo" = '(100, 1)
--- | Cuban peso
-type instance I.Scale "CUP" "CUP" = '(100, 1)
-type instance I.Scale "CUP" "peso" = '(1, 1)
-type instance I.Scale "CUP" "centavo" = '(100, 1)
--- | Cape Verdean escudo
-type instance I.Scale "CVE" "CVE" = '(100, 1)
-type instance I.Scale "CVE" "escudo" = '(1, 1)
-type instance I.Scale "CVE" "centavo" = '(100, 1)
--- | Czech koruna
-type instance I.Scale "CZK" "CZK" = '(100, 1)
-type instance I.Scale "CZK" "koruna" = '(1, 1)
-type instance I.Scale "CZK" "haler" = '(100, 1)
--- | Djiboutian franc
-type instance I.Scale "DJF" "DJF" = '(100, 1)
-type instance I.Scale "DJF" "franc" = '(1, 1)
-type instance I.Scale "DJF" "centime" = '(100, 1)
--- | Danish krone
-type instance I.Scale "DKK" "DKK" = '(100, 1)
-type instance I.Scale "DKK" "krone" = '(1, 1)
-type instance I.Scale "DKK" "ore" = '(100, 1)
--- | Dominican peso
-type instance I.Scale "DOP" "DOP" = '(100, 1)
-type instance I.Scale "DOP" "peso" = '(1, 1)
-type instance I.Scale "DOP" "centavo" = '(100, 1)
--- | Algerian dinar
-type instance I.Scale "DZD" "DZD" = '(100, 1)
-type instance I.Scale "DZD" "dinar" = '(1, 1)
-type instance I.Scale "DZD" "santeem" = '(100, 1)
--- | Egyptian pound
-type instance I.Scale "EGP" "EGP" = '(100, 1)
-type instance I.Scale "EGP" "pound" = '(1, 1)
-type instance I.Scale "EGP" "piastre" = '(100, 1)
--- | Eritrean nakfa
-type instance I.Scale "ERN" "ERN" = '(100, 1)
-type instance I.Scale "ERN" "nafka" = '(1, 1)
-type instance I.Scale "ERN" "cent" = '(100, 1)
--- | Ethiopian birr
-type instance I.Scale "ETB" "ETB" = '(100, 1)
-type instance I.Scale "ETB" "birr" = '(1, 1)
-type instance I.Scale "ETB" "santim" = '(100, 1)
--- | European euro
-type instance I.Scale "EUR" "EUR" = '(100, 1)
-type instance I.Scale "EUR" "euro" = '(1, 1)
-type instance I.Scale "EUR" "cent" = '(100, 1)
--- | Fijian dollar
-type instance I.Scale "FJD" "FJD" = '(100, 1)
--- | Falkland Islands pound
-type instance I.Scale "FKP" "FKP" = '(100, 1)
-type instance I.Scale "FKP" "pound" = '(1, 1)
-type instance I.Scale "FKP" "penny" = '(100, 1)
--- | Pound sterling
-type instance I.Scale "GBP" "GBP" = '(100, 1)
-type instance I.Scale "GBP" "pound" = '(1, 1)
-type instance I.Scale "GBP" "penny" = '(100, 1)
--- | Georgian lari
-type instance I.Scale "GEL" "GEL" = '(100, 1)
-type instance I.Scale "GEL" "lari" = '(1, 1)
-type instance I.Scale "GEL" "tetri" = '(100, 1)
--- | Ghanaian cedi
-type instance I.Scale "GHS" "GHS" = '(100, 1)
-type instance I.Scale "GHS" "cedi" = '(1, 1)
-type instance I.Scale "GHS" "pesewa" = '(100, 1)
--- | Gibraltar pound
-type instance I.Scale "GIP" "GIP" = '(100, 1)
-type instance I.Scale "GIP" "pound" = '(1, 1)
-type instance I.Scale "GIP" "penny" = '(100, 1)
--- | Gambian dalasi
-type instance I.Scale "GMD" "GMD" = '(100, 1)
-type instance I.Scale "GMD" "dalasi" = '(1, 1)
-type instance I.Scale "GMD" "butut" = '(100, 1)
--- | Guinean franc
-type instance I.Scale "GNF" "GNF" = '(100, 1)
-type instance I.Scale "GNF" "franc" = '(1, 1)
-type instance I.Scale "GNF" "centime" = '(100, 1)
--- | Guatemalan quetzal
-type instance I.Scale "GTQ" "GTQ" = '(100, 1)
-type instance I.Scale "GTQ" "quetzal" = '(1, 1)
-type instance I.Scale "GTQ" "centavo" = '(100, 1)
--- | Guyanese dollar
-type instance I.Scale "GYD" "GYD" = '(100, 1)
-type instance I.Scale "GYD" "dollar" = '(1, 1)
-type instance I.Scale "GYD" "cent" = '(100, 1)
--- | Hong Kong dollar
-type instance I.Scale "HKD" "HKD" = '(100, 1)
-type instance I.Scale "HKD" "dollar" = '(1, 1)
-type instance I.Scale "HKD" "cent" = '(100, 1)
--- | Honduran lempira
-type instance I.Scale "HNL" "HNL" = '(100, 1)
-type instance I.Scale "HNL" "lempira" = '(1, 1)
-type instance I.Scale "HNL" "centavo" = '(100, 1)
--- | Croatian kuna
-type instance I.Scale "HRK" "HRK" = '(100, 1)
-type instance I.Scale "HRK" "kuna" = '(1, 1)
-type instance I.Scale "HRK" "lipa" = '(100, 1)
--- | Haitian gourde
-type instance I.Scale "HTG" "HTG" = '(100, 1)
-type instance I.Scale "HTG" "gourde" = '(1, 1)
-type instance I.Scale "HTG" "centime" = '(1, 1)
--- | Hungarian forint
-type instance I.Scale "HUF" "HUF" = '(100, 1)
-type instance I.Scale "HUF" "forint" = '(1, 1)
-type instance I.Scale "HUF" "filler" = '(100, 1)
--- | Indonesian rupiah
-type instance I.Scale "IDR" "IDR" = '(100, 1)
-type instance I.Scale "IDR" "rupiah" = '(1, 1)
-type instance I.Scale "IDR" "sen" = '(100, 1)
--- | Israeli new shekel
-type instance I.Scale "ILS" "ILS" = '(100, 1)
-type instance I.Scale "ILS" "shekel" = '(1, 1)
-type instance I.Scale "ILS" "agora" = '(100, 1)
--- | Indian rupee
-type instance I.Scale "INR" "INR" = '(100, 1)
-type instance I.Scale "INR" "rupee" = '(1, 1)
-type instance I.Scale "INR" "paisa" = '(100, 1)
--- | Iraqi dinar
-type instance I.Scale "IQD" "IQD" = '(1000, 1)
-type instance I.Scale "IQD" "dinar" = '(1, 1)
-type instance I.Scale "IQD" "fils" = '(1000, 1)
--- | Iranian rial
-type instance I.Scale "IRR" "IRR" = '(100, 1)
-type instance I.Scale "IRR" "rial" = '(1, 1)
-type instance I.Scale "IRR" "dinar" = '(100, 1)
--- | Icelandic króna
-type instance I.Scale "ISK" "ISK" = '(100, 1)
-type instance I.Scale "ISK" "krona" = '(1, 1)
-type instance I.Scale "ISK" "eyir" = '(100, 1)
--- | Jamaican dollar
-type instance I.Scale "JMD" "JMD" = '(100, 1)
-type instance I.Scale "JMD" "dollar" = '(1, 1)
-type instance I.Scale "JMD" "cent" = '(100, 1)
--- | Jordanian dinar
-type instance I.Scale "JOD" "JOD" = '(100, 1)
-type instance I.Scale "JOD" "dinar" = '(1, 1)
-type instance I.Scale "JOD" "piastre" = '(100, 1)
--- | Japanese yen
-type instance I.Scale "JPY" "JPY" = '(100, 1)
-type instance I.Scale "JPY" "yen" = '(1, 1)
-type instance I.Scale "JPY" "sen" = '(100, 1)
--- | Kenyan shilling
-type instance I.Scale "KES" "KES" = '(100, 1)
-type instance I.Scale "KES" "shilling" = '(1, 1)
-type instance I.Scale "KES" "cent" = '(100, 1)
--- | Kyrgyzstani som
-type instance I.Scale "KGS" "KGS" = '(100, 1)
-type instance I.Scale "KGS" "som" = '(1, 1)
-type instance I.Scale "KGS" "tyiyn" = '(100, 1)
--- | Cambodian riel
-type instance I.Scale "KHR" "KHR" = '(100, 1)
-type instance I.Scale "KHR" "riel" = '(1, 1)
-type instance I.Scale "KHR" "sen" = '(100, 1)
--- | Comorian franc
-type instance I.Scale "KMF" "KMF" = '(100, 1)
-type instance I.Scale "KMF" "franc" = '(1, 1)
-type instance I.Scale "KMF" "centime" = '(100, 1)
--- | North Korean won
-type instance I.Scale "KPW" "KPW" = '(100, 1)
-type instance I.Scale "KPW" "won" = '(1, 1)
-type instance I.Scale "KPW" "chon" = '(100, 1)
--- | South Korean won
-type instance I.Scale "KRW" "KRW" = '(100, 1)
-type instance I.Scale "KRW" "won" = '(1, 1)
-type instance I.Scale "KRW" "jeon" = '(100, 1)
--- | Kuwaiti dinar
-type instance I.Scale "KWD" "KWD" = '(1000, 1)
-type instance I.Scale "KWD" "dinar" = '(1, 1)
-type instance I.Scale "KWD" "fils" = '(1000, 1)
--- | Cayman Islands dollar
-type instance I.Scale "KYD" "KYD" = '(100, 1)
-type instance I.Scale "KYD" "dollar" = '(1, 1)
-type instance I.Scale "KYD" "cent" = '(100, 1)
--- | Kazakhstani tenge
-type instance I.Scale "KZT" "KZT" = '(100, 1)
-type instance I.Scale "KZT" "tenge" = '(1, 1)
-type instance I.Scale "KZT" "tiyin" = '(100, 1)
--- | Lao kip
-type instance I.Scale "LAK" "LAK" = '(100, 1)
-type instance I.Scale "LAK" "kip" = '(1, 1)
-type instance I.Scale "LAK" "att" = '(100, 1)
--- | Lebanese pound
-type instance I.Scale "LBP" "LBP" = '(100, 1)
-type instance I.Scale "LBP" "pound" = '(1, 1)
-type instance I.Scale "LBP" "piastre" = '(100, 1)
--- | Sri Lankan rupee
-type instance I.Scale "LKR" "LKR" = '(100, 1)
-type instance I.Scale "LKR" "rupee" = '(1, 1)
-type instance I.Scale "LKR" "cent" = '(100, 1)
--- | Liberian dollar
-type instance I.Scale "LRD" "LRD" = '(100, 1)
-type instance I.Scale "LRD" "dollar" = '(1, 1)
-type instance I.Scale "LRD" "cent" = '(100, 1)
--- | Lesotho loti
-type instance I.Scale "LSL" "LSL" = '(100, 1)
-type instance I.Scale "LSL" "loti" = '(1, 1)
-type instance I.Scale "LSL" "sente" = '(100, 1)
--- | Libyan dinar
-type instance I.Scale "LYD" "LYD" = '(100, 1)
-type instance I.Scale "LYD" "dinar" = '(1, 1)
-type instance I.Scale "LYD" "dirham" = '(1000, 1)
--- | Moroccan dirham
-type instance I.Scale "MAD" "MAD" = '(100, 1)
-type instance I.Scale "MAD" "dirham" = '(1, 1)
-type instance I.Scale "MAD" "centime" = '(100, 1)
--- | Moldovan leu
-type instance I.Scale "MDL" "MDL" = '(100, 1)
-type instance I.Scale "MDL" "leu" = '(100, 1)
-type instance I.Scale "MDL" "ban" = '(100, 1)
--- | Malagasy ariary
-type instance I.Scale "MGA" "MGA" = '(5, 1)
-type instance I.Scale "MGA" "ariary" = '(1, 1)
-type instance I.Scale "MGA" "iraimbilanja" = '(5, 1)
--- | Macedonian denar
-type instance I.Scale "MKD" "MKD" = '(100, 1)
-type instance I.Scale "MKD" "denar" = '(1, 1)
-type instance I.Scale "MKD" "deni" = '(100, 1)
--- | Myanmar kyat
-type instance I.Scale "MMK" "MMK" = '(100, 1)
-type instance I.Scale "MMK" "kyat" = '(1, 1)
-type instance I.Scale "MMK" "pya" = '(100, 1)
--- | Mongolian tugrik
-type instance I.Scale "MNT" "MNT" = '(100, 1)
-type instance I.Scale "MNT" "tugrik" = '(1, 1)
-type instance I.Scale "MNT" "mongo" = '(100, 1)
--- | Macanese pataca
-type instance I.Scale "MOP" "MOP" = '(100, 1)
-type instance I.Scale "MOP" "pataca" = '(1, 1)
-type instance I.Scale "MOP" "avo" = '(100, 1)
--- | Mauritanian ouguiya
-type instance I.Scale "MRO" "MRO" = '(5, 1)
-type instance I.Scale "MRO" "ouguiya" = '(1, 1)
-type instance I.Scale "MRO" "khoums" = '(5, 1)
--- | Mauritian rupee
-type instance I.Scale "MUR" "MUR" = '(100, 1)
-type instance I.Scale "MUR" "rupee" = '(1, 1)
-type instance I.Scale "MUR" "cent" = '(100, 1)
--- | Maldivian rufiyaa
-type instance I.Scale "MVR" "MVR" = '(100, 1)
-type instance I.Scale "MVR" "rufiyaa" = '(1, 1)
-type instance I.Scale "MVR" "laari" = '(100, 1)
--- | Malawian kwacha
-type instance I.Scale "MWK" "MWK" = '(100, 1)
-type instance I.Scale "MWK" "kwacha" = '(1, 1)
-type instance I.Scale "MWK" "tambala" = '(100, 1)
--- | Mexican peso
-type instance I.Scale "MXN" "MXN" = '(100, 1)
-type instance I.Scale "MXN" "peso" = '(1, 1)
-type instance I.Scale "MXN" "centavo" = '(100, 1)
--- | Mexican unidad de inversion
-type instance I.Scale "MXV" "MXV" = '(100, 1)
--- | Malaysian ringgit
-type instance I.Scale "MYR" "MYR" = '(100, 1)
-type instance I.Scale "MYR" "ringgit" = '(1, 1)
-type instance I.Scale "MYR" "sen" = '(100, 1)
--- | Mozambican metical
-type instance I.Scale "MZN" "MZN" = '(100, 1)
-type instance I.Scale "MZN" "metical" = '(1, 1)
-type instance I.Scale "MZN" "centavo" = '(100, 1)
--- | Namibian dollar
-type instance I.Scale "NAD" "NAD" = '(100, 1)
-type instance I.Scale "NAD" "dollar" = '(1, 1)
-type instance I.Scale "NAD" "cent" = '(100, 1)
--- | Nigerian naira
-type instance I.Scale "NGN" "NGN" = '(100, 1)
-type instance I.Scale "NGN" "naira" = '(1, 1)
-type instance I.Scale "NGN" "kobo" = '(100, 1)
--- | Nicaraguan cordoba
-type instance I.Scale "NIO" "NIO" = '(100, 1)
-type instance I.Scale "NIO" "cordoba" = '(1, 1)
-type instance I.Scale "NIO" "centavo" = '(100, 1)
--- | Norwegian krone
-type instance I.Scale "NOK" "NOK" = '(100, 1)
-type instance I.Scale "NOK" "krone" = '(1, 1)
-type instance I.Scale "NOK" "ore" = '(100, 1)
--- | Nepalese rupee
-type instance I.Scale "NPR" "NPR" = '(100, 1)
-type instance I.Scale "NPR" "rupee" = '(1, 1)
-type instance I.Scale "NPR" "paisa" = '(100, 1)
--- | New Zealand dollar
-type instance I.Scale "NZD" "NZD" = '(100, 1)
-type instance I.Scale "NZD" "dollar" = '(1, 1)
-type instance I.Scale "NZD" "cent" = '(100, 1)
--- | Omani rial
-type instance I.Scale "OMR" "OMR" = '(1000, 1)
-type instance I.Scale "OMR" "rial" = '(1, 1)
-type instance I.Scale "OMR" "baisa" = '(1000, 1)
--- | Panamenian balboa
-type instance I.Scale "PAB" "PAB" = '(100, 1)
-type instance I.Scale "PAB" "balboa" = '(1, 1)
-type instance I.Scale "PAB" "centesimo" = '(100, 1)
--- | Peruvian sol
-type instance I.Scale "PEN" "PEN" = '(100, 1)
-type instance I.Scale "PEN" "sol" = '(1, 1)
-type instance I.Scale "PEN" "centimo" = '(100, 1)
--- | Papua New Guinean kina
-type instance I.Scale "PGK" "PGK" = '(100, 1)
-type instance I.Scale "PGK" "kina" = '(1, 1)
-type instance I.Scale "PGK" "toea" = '(100, 1)
--- | Philippine peso
-type instance I.Scale "PHP" "PHP" = '(100, 1)
-type instance I.Scale "PHP" "peso" = '(1, 1)
-type instance I.Scale "PHP" "centavo" = '(100, 1)
--- | Pakistani rupee
-type instance I.Scale "PKR" "PKR" = '(100, 1)
-type instance I.Scale "PKR" "rupee" = '(1, 1)
-type instance I.Scale "PKR" "paisa" = '(100, 1)
--- | Polish zloty
-type instance I.Scale "PLN" "PLN" = '(100, 1)
-type instance I.Scale "PLN" "zloty" = '(1, 1)
-type instance I.Scale "PLN" "grosz" = '(100, 1)
--- | Paraguayan guarani
-type instance I.Scale "PYG" "PYG" = '(100, 1)
-type instance I.Scale "PYG" "guarani" = '(1, 1)
-type instance I.Scale "PYG" "centimo" = '(100, 1)
--- | Qatari riyal
-type instance I.Scale "QAR" "QAR" = '(100, 1)
-type instance I.Scale "QAR" "riyal" = '(1, 1)
-type instance I.Scale "QAR" "dirham" = '(100, 1)
--- | Romanian leu
-type instance I.Scale "RON" "RON" = '(100, 1)
-type instance I.Scale "RON" "leu" = '(1, 1)
-type instance I.Scale "RON" "ban" = '(100, 1)
--- | Serbian dinar
-type instance I.Scale "RSD" "RSD" = '(100, 1)
-type instance I.Scale "RSD" "dinar" = '(1, 1)
-type instance I.Scale "RSD" "para" = '(100, 1)
--- | Russian ruble
-type instance I.Scale "RUB" "RUB" = '(100, 1)
-type instance I.Scale "RUB" "ruble" = '(1, 1)
-type instance I.Scale "RUB" "kopek" = '(100, 1)
--- | Rwandan franc
-type instance I.Scale "RWF" "RWF" = '(100, 1)
-type instance I.Scale "RWF" "franc" = '(1, 1)
-type instance I.Scale "RWF" "centime" = '(100, 1)
--- | Saudi Arabian riyal
-type instance I.Scale "SAR" "SAR" = '(100, 1)
-type instance I.Scale "SAR" "riyal" = '(1, 1)
-type instance I.Scale "SAR" "halala" = '(100, 1)
--- | Solomon Islands dollar
-type instance I.Scale "SBD" "SBD" = '(100, 1)
-type instance I.Scale "SBD" "dollar" = '(100, 1)
-type instance I.Scale "SBD" "cent" = '(100, 1)
--- | Seychellois rupee
-type instance I.Scale "SCR" "SCR" = '(100, 1)
-type instance I.Scale "SCR" "rupee" = '(1, 1)
-type instance I.Scale "SCR" "cent" = '(100, 1)
--- | Sudanese pound
-type instance I.Scale "SDG" "SDG" = '(100, 1)
-type instance I.Scale "SDG" "pound" = '(1, 1)
-type instance I.Scale "SDG" "piastre" = '(100, 1)
--- | Swedish krona
-type instance I.Scale "SEK" "SEK" = '(100, 1)
-type instance I.Scale "SEK" "krona" = '(1, 1)
-type instance I.Scale "SEK" "ore" = '(100, 1)
--- | Singapore dollar
-type instance I.Scale "SGD" "SGD" = '(100, 1)
-type instance I.Scale "SGD" "dollar" = '(1, 1)
-type instance I.Scale "SGD" "cent" = '(100, 1)
--- | Saint Helena pound
-type instance I.Scale "SHP" "SHP" = '(100, 1)
-type instance I.Scale "SHP" "pound" = '(1, 1)
-type instance I.Scale "SHP" "penny" = '(100, 1)
--- | Sierra Leonean leone
-type instance I.Scale "SLL" "SLL" = '(100, 1)
-type instance I.Scale "SLL" "leone" = '(1, 1)
-type instance I.Scale "SLL" "cent" = '(100, 1)
--- | Somali shilling
-type instance I.Scale "SOS" "SOS" = '(100, 1)
-type instance I.Scale "SOS" "shilling" = '(1, 1)
-type instance I.Scale "SOS" "cent" = '(100, 1)
--- | Surinamese dollar
-type instance I.Scale "SRD" "SRD" = '(100, 1)
-type instance I.Scale "SRD" "dollar" = '(1, 1)
-type instance I.Scale "SRD" "cent" = '(100, 1)
--- | South Sudanese pound
-type instance I.Scale "SSP" "SSP" = '(100, 1)
-type instance I.Scale "SSP" "pound" = '(1, 1)
-type instance I.Scale "SSP" "piastre" = '(100, 1)
--- | Sao Tome and Principe dobra
-type instance I.Scale "STD" "STD" = '(100, 1)
-type instance I.Scale "STD" "dobra" = '(1, 1)
-type instance I.Scale "STD" "centimo" = '(100, 1)
--- | Salvadoran colon
-type instance I.Scale "SVC" "SVC" = '(100, 1)
-type instance I.Scale "SVC" "colon" = '(1, 1)
-type instance I.Scale "SVC" "centavo" = '(100, 1)
--- | Syrian pound
-type instance I.Scale "SYP" "SYP" = '(100, 1)
-type instance I.Scale "SYP" "pound" = '(1, 1)
-type instance I.Scale "SYP" "piastre" = '(100, 1)
--- | Swazi lilangeni
-type instance I.Scale "SZL" "SZL" = '(100, 1)
-type instance I.Scale "SZL" "lilangeni" = '(1, 1)
-type instance I.Scale "SZL" "cent" = '(100, 1)
--- | Thai baht
-type instance I.Scale "THB" "THB" = '(100, 1)
-type instance I.Scale "THB" "baht" = '(1, 1)
-type instance I.Scale "THB" "satang" = '(100, 1)
--- | Tajikistani somoni
-type instance I.Scale "TJS" "TJS" = '(100, 1)
-type instance I.Scale "TJS" "somoni" = '(1, 1)
-type instance I.Scale "TJS" "diram" = '(100, 1)
--- | Turkmen manat
-type instance I.Scale "TMT" "TMT" = '(100, 1)
-type instance I.Scale "TMT" "manat" = '(1, 1)
-type instance I.Scale "TMT" "tennesi" = '(100, 1)
--- | Tunisian dinar
-type instance I.Scale "TND" "TND" = '(1000, 1)
-type instance I.Scale "TND" "dinar" = '(1, 1)
-type instance I.Scale "TND" "millime" = '(1000, 1)
--- | Tongan pa’anga
-type instance I.Scale "TOP" "TOP" = '(100, 1)
-type instance I.Scale "TOP" "pa'anga" = '(1, 1)
-type instance I.Scale "TOP" "seniti" = '(100, 1)
--- | Turkish lira
-type instance I.Scale "TRY" "TRY" = '(100, 1)
-type instance I.Scale "TRY" "lira" = '(1, 1)
-type instance I.Scale "TRY" "kurus" = '(100, 1)
--- | Tobago Trinidad and Tobago dollar
-type instance I.Scale "TTD" "TTD" = '(100, 1)
-type instance I.Scale "TTD" "dollar" = '(1, 1)
-type instance I.Scale "TTD" "cent" = '(100, 1)
--- | New Taiwan dollar
-type instance I.Scale "TWD" "TWD" = '(100, 1)
-type instance I.Scale "TWD" "dollar" = '(1, 1)
-type instance I.Scale "TWD" "cent" = '(100, 1)
--- | Tanzanian shilling
-type instance I.Scale "TZS" "TZS" = '(100, 1)
-type instance I.Scale "TZS" "shilling" = '(1, 1)
-type instance I.Scale "TZS" "cent" = '(100, 1)
--- | Ukrainian hryvnia
-type instance I.Scale "UAH" "UAH" = '(100, 1)
-type instance I.Scale "UAH" "hryvnia" = '(1, 1)
-type instance I.Scale "UAH" "kopiyka" = '(100, 1)
--- | Ugandan shilling
-type instance I.Scale "UGX" "UGX" = '(100, 1)
-type instance I.Scale "UGX" "shilling" = '(1, 1)
-type instance I.Scale "UGX" "cent" = '(100, 1)
--- | United States dollar
-type instance I.Scale "USD" "USD" = '(100, 1)
-type instance I.Scale "USD" "dollar" = '(1, 1)
-type instance I.Scale "USD" "cent" = '(100, 1)
--- | United States dollar (next day)
-type instance I.Scale "USN" "USN" = '(100, 1)
--- | Uruguayan peso en unidades
-type instance I.Scale "UYI" "UYI" = '(100, 1)
--- | Uruguayan peso
-type instance I.Scale "UYU" "UYU" = '(100, 1)
-type instance I.Scale "UYU" "peso" = '(1, 1)
-type instance I.Scale "UYU" "centesimo" = '(100, 1)
--- | Uzbekistani som
-type instance I.Scale "UZS" "UZS" = '(100, 1)
-type instance I.Scale "UZS" "som" = '(1, 1)
-type instance I.Scale "UZS" "tiyin" = '(100, 1)
--- | Venezuelan bolivar
-type instance I.Scale "VEF" "VEF" = '(100, 1)
-type instance I.Scale "VEF" "bolivar" = '(1, 1)
-type instance I.Scale "VEF" "centimo" = '(100, 1)
--- | Vietnamese dong
-type instance I.Scale "VND" "VND" = '(10, 1)
-type instance I.Scale "VND" "dong" = '(1, 1)
-type instance I.Scale "VND" "hao" = '(10, 1)
--- | Vanuatu vatu
-type instance I.Scale "VUV" "VUV" = '(1, 1)
-type instance I.Scale "VUV" "vatu" = '(1, 1)
--- | Samoan tālā
-type instance I.Scale "WST" "WST" = '(100, 1)
-type instance I.Scale "WST" "tala" = '(1, 1)
-type instance I.Scale "WST" "sene" = '(100, 1)
--- | Central African CFA franc
-type instance I.Scale "XAF" "XAF" = '(100, 1)
-type instance I.Scale "XAF" "franc" = '(1, 1)
-type instance I.Scale "XAF" "centime" = '(100, 1)
--- | East Caribbean dollar
-type instance I.Scale "XCD" "XCD" = '(100, 1)
-type instance I.Scale "XCD" "dollar" = '(1, 1)
-type instance I.Scale "XCD" "cent" = '(100, 1)
--- | International Monetary Fund Special Drawing Right
-type instance I.Scale "XDR" "XDR" = '(100, 1)
--- | West African CFA franc
-type instance I.Scale "XOF" "XOF" = '(100, 1)
-type instance I.Scale "XOF" "franc" = '(1, 1)
-type instance I.Scale "XOF" "centime" = '(100, 1)
--- | CFP franc
-type instance I.Scale "XPF" "XPF" = '(100, 1)
-type instance I.Scale "XPF" "franc" = '(1, 1)
-type instance I.Scale "XPF" "centime" = '(100, 1)
--- | Sucre
-type instance I.Scale "XSU" "XSU" = '(100, 1)
--- | African Development Bank unit of account
-type instance I.Scale "XUA" "XUA" = '(100, 1)
--- | Yemeni rial
-type instance I.Scale "YER" "YER" = '(100, 1)
-type instance I.Scale "YER" "rial" = '(1, 1)
-type instance I.Scale "YER" "fils" = '(100, 1)
--- | South African rand
-type instance I.Scale "ZAR" "ZAR" = '(100, 1)
-type instance I.Scale "ZAR" "rand" = '(1, 1)
-type instance I.Scale "ZAR" "cent" = '(100, 1)
--- | Zambian kwacha
-type instance I.Scale "ZMW" "ZMW" = '(100, 1)
-type instance I.Scale "ZMW" "kwacha" = '(1, 1)
-type instance I.Scale "ZMW" "ngwee" = '(100, 1)
--- | Zimbawe dollar
-type instance I.Scale "ZWL" "ZWL" = '(100, 1)
-type instance I.Scale "ZWL" "dollar" = '(1, 1)
-type instance I.Scale "ZWL" "cent" = '(100, 1)
-
--- | Gold. No canonical smallest unit. Unusable instance.
-type instance I.Scale "XAU" "XAU" = I.ErrScaleNonCanonical "XAU"
-type instance I.Scale "XAU" "troy-ounce" = '(1, 1)
-type instance I.Scale "XAU" "grain" = '(480, 1)
-type instance I.Scale "XAU" "milligrain" = '(480000, 1)
-type instance I.Scale "XAU" "micrograin" = '(480000000, 1)
-type instance I.Scale "XAU" "kilogram" = '(31103477, 1000000000)
-type instance I.Scale "XAU" "gram" = '(31103477, 1000000)
-type instance I.Scale "XAU" "milligram" = '(31103477, 1000)
-type instance I.Scale "XAU" "microgram" = '(31103477, 1)
-
--- | Silver. No canonical smallest unit. Unusable instance.
-type instance I.Scale "XAG" "XAG" = I.ErrScaleNonCanonical "XAG"
-type instance I.Scale "XAG" "troy-ounce" = '(1, 1)
-type instance I.Scale "XAG" "grain" = '(480, 1)
-type instance I.Scale "XAG" "milligrain" = '(480000, 1)
-type instance I.Scale "XAG" "micrograin" = '(480000000, 1)
-type instance I.Scale "XAG" "kilogram" = '(31103477, 1000000000)
-type instance I.Scale "XAG" "gram" = '(31103477, 1000000)
-type instance I.Scale "XAG" "milligram" = '(31103477, 1000)
-type instance I.Scale "XAG" "microgram" = '(31103477, 1)
-
--- | Palladium. No canonical smallest unit. Unusable instance.
-type instance I.Scale "XPD" "XPD" = I.ErrScaleNonCanonical "XPD"
-type instance I.Scale "XPD" "troy-ounce" = '(1, 1)
-type instance I.Scale "XPD" "grain" = '(480, 1)
-type instance I.Scale "XPD" "milligrain" = '(480000, 1)
-type instance I.Scale "XPD" "micrograin" = '(480000000, 1)
-type instance I.Scale "XPD" "kilogram" = '(31103477, 1000000000)
-type instance I.Scale "XPD" "gram" = '(31103477, 1000000)
-type instance I.Scale "XPD" "milligram" = '(31103477, 1000)
-type instance I.Scale "XPD" "microgram" = '(31103477, 1)
-
--- | Platinum. No canonical smallest unit. Unusable instance.
-type instance I.Scale "XPT" "XPT" = I.ErrScaleNonCanonical "XPT"
-type instance I.Scale "XPT" "troy-ounce" = '(1, 1)
-type instance I.Scale "XPT" "grain" = '(480, 1)
-type instance I.Scale "XPT" "milligrain" = '(480000, 1)
-type instance I.Scale "XPT" "micrograin" = '(480000000, 1)
-type instance I.Scale "XPT" "kilogram" = '(31103477, 1000000000)
-type instance I.Scale "XPT" "gram" = '(31103477, 1000000)
-type instance I.Scale "XPT" "milligram" = '(31103477, 1000)
-type instance I.Scale "XPT" "microgram" = '(31103477, 1)
-
--- | Bitcoin
-type instance I.Scale "BTC" "BTC" = '(100000000, 1)
-type instance I.Scale "BTC" "bitcoin" = '(1, 1)
-type instance I.Scale "BTC" "satoshi" = '(100000000, 1)
-
--- | Bitcoin
-type instance I.Scale "XBT" "XBT" = '(100000000, 1)
-type instance I.Scale "XBT" "bitcoin" = '(1, 1)
-type instance I.Scale "XBT" "satoshi" = '(100000000, 1)
-
--- | Ether
-type instance I.Scale "ETH" "ETH" = '(1000000000000000000, 1)
-type instance I.Scale "ETH" "ether" = '(1, 1)
-type instance I.Scale "ETH" "kwei" = '(1000, 1)
-type instance I.Scale "ETH" "babbage" = '(1000, 1)
-type instance I.Scale "ETH" "mwei" = '(1000000, 1)
-type instance I.Scale "ETH" "lovelace" = '(1000000, 1)
-type instance I.Scale "ETH" "gwei" = '(1000000000, 1)
-type instance I.Scale "ETH" "shannon" = '(1000000000, 1)
-type instance I.Scale "ETH" "microether" = '(1000000000000, 1)
-type instance I.Scale "ETH" "szabo" = '(1000000000000, 1)
-type instance I.Scale "ETH" "finney" = '(1000000000000000, 1)
-type instance I.Scale "ETH" "milliether" = '(1000000000000000, 1)
-type instance I.Scale "ETH" "wei" = '(1000000000000000000, 1)
diff --git a/src/Data/Money/Internal.hs b/src/Data/Money/Internal.hs
deleted file mode 100644
--- a/src/Data/Money/Internal.hs
+++ /dev/null
@@ -1,1140 +0,0 @@
-{-# LANGUAGE BangPatterns #-}
-{-# LANGUAGE CPP #-}
-{-# LANGUAGE ConstraintKinds #-}
-{-# LANGUAGE DataKinds #-}
-{-# LANGUAGE DeriveGeneric #-}
-{-# LANGUAGE FlexibleContexts #-}
-{-# LANGUAGE GeneralizedNewtypeDeriving #-}
-{-# LANGUAGE KindSignatures #-}
-{-# LANGUAGE LambdaCase #-}
-{-# LANGUAGE PolyKinds #-}
-{-# LANGUAGE RankNTypes #-}
-{-# LANGUAGE ScopedTypeVariables #-}
-{-# LANGUAGE StandaloneDeriving #-}
-{-# LANGUAGE TypeFamilies #-}
-{-# LANGUAGE TypeOperators #-}
-{-# LANGUAGE UndecidableInstances #-}
-
-#if MIN_VERSION_base(4,9,0)
-{-# OPTIONS_GHC -Wno-redundant-constraints #-}
-#endif
-
--- | This is an internal module. Import "Data.Money" instead.
-module Data.Money.Internal
- ( -- * Dense monetary values
-   Dense
- , dense
-   -- * Discrete monetary values
- , Discrete
- , Discrete'
- , fromDiscrete
- , round
- , ceiling
- , floor
- , truncate
-   -- * Currency scales
- , Scale
- , GoodScale
- , ErrScaleNonCanonical
- , scale
-   -- * Currency exchange
- , ExchangeRate
- , exchangeRate
- , fromExchangeRate
- , flipExchangeRate
- , exchange
-   -- * Serializable representations
- , DenseRep
- , denseRep
- , denseRepCurrency
- , denseRepAmount
- , denseRepAmountNumerator
- , denseRepAmountDenominator
- , mkDenseRep
- , fromDenseRep
- , withDenseRep
- , DiscreteRep
- , discreteRep
- , discreteRepCurrency
- , discreteRepScale
- , discreteRepScaleNumerator
- , discreteRepScaleDenominator
- , discreteRepAmount
- , mkDiscreteRep
- , fromDiscreteRep
- , withDiscreteRep
- , ExchangeRateRep
- , exchangeRateRep
- , exchangeRateRepSrcCurrency
- , exchangeRateRepDstCurrency
- , exchangeRateRepRate
- , exchangeRateRepRateNumerator
- , exchangeRateRepRateDenominator
- , mkExchangeRateRep
- , fromExchangeRateRep
- , withExchangeRateRep
- ) where
-
-import Control.Applicative (empty)
-import Control.Monad ((<=<))
-import Data.Constraint (Dict(Dict))
-import Data.Proxy (Proxy(..))
-import Data.Ratio ((%), numerator, denominator)
-import qualified GHC.Generics as GHC
-import GHC.Real (infinity, notANumber)
-import GHC.TypeLits
-  (Symbol, SomeSymbol(..), Nat, SomeNat(..), CmpNat, KnownSymbol, KnownNat,
-   natVal, someNatVal, symbolVal, someSymbolVal)
-import Prelude hiding (round, ceiling, floor, truncate)
-import qualified Prelude
-import qualified Text.ParserCombinators.ReadPrec as ReadPrec
-import qualified Text.ParserCombinators.ReadP as ReadP
-import Text.Read (readPrec)
-import Unsafe.Coerce (unsafeCoerce)
-
-#ifdef VERSION_aeson
-import qualified Data.Aeson as Ae
-#endif
-
-#ifdef VERSION_binary
-import qualified Data.Binary as Binary
-#endif
-
-#ifdef VERSION_cereal
-import qualified Data.Serialize as Cereal
-#endif
-
-#ifdef VERSION_deepseq
-import Control.DeepSeq (NFData)
-#endif
-
-#ifdef VERSION_hashable
-import Data.Hashable (Hashable)
-#endif
-
-#ifdef VERSION_store
-import qualified Data.Store as Store
-#endif
-
-#if MIN_VERSION_base(4,9,0)
-import qualified GHC.TypeLits as GHC
-#endif
-
---------------------------------------------------------------------------------
--- | 'Dense' represents a dense monetary value for @currency@ (usually a
--- ISO-4217 currency code, but not necessarily) as a rational number.
---
--- While monetary values associated with a particular currency are discrete, you
--- can still treat monetary values as dense while operating on them. For
--- example, the half of @USD 3.41@ is @USD 1.705@, which is not an amount that
--- can't be represented as a number of USD cents (the smallest unit that can
--- represent USD amounts). Nevertheless, if you eventually multiply @USD 1.705@
--- by @4@, for example, you end up with @USD 6.82@, which is again a value
--- representable as USD cents. In other words, 'Dense' monetary values
--- allow us to perform precise calculations deferring the conversion to a
--- 'Discrete' monetary values as much as posible. Once you are ready to
--- aproximate a 'Dense' value to a 'Discrete' value you can use one of
--- 'round', 'floor', 'ceiling' or 'truncate'. Otherwise, using 'toRational' you
--- can obtain a precise 'Rational' representation.
---
--- Construct 'Dense' monetary values using 'dense', or
--- 'fromInteger' / 'fromIntegral' if that suffices.
---
--- /WARNING/ if you want to treat a dense monetary value as a /Real/ number (for
--- example, to take the square root of that monetary value), then you are on
--- your own. We can only guarantee lossless manipulation of rational values, so
--- you will need to convert back and forth betwen the 'Rational' representation
--- for 'Dense' and your (likely lossy) representation for /Real/ numbers.
-newtype Dense (currency :: Symbol) = Dense Rational
-  deriving (Eq, Ord, Num, Real, Fractional, GHC.Generic)
-
-instance forall currency. KnownSymbol currency => Show (Dense currency) where
-  show = \(Dense r0) ->
-    let c = symbolVal (Proxy :: Proxy currency)
-    in concat [ "Dense ", show c, " (", show r0, ")" ]
-
-instance forall currency. KnownSymbol currency => Read (Dense currency) where
-  readPrec = do
-    let c = symbolVal (Proxy :: Proxy currency)
-    _ <- ReadPrec.lift (ReadP.string ("Dense " ++ show c ++ " "))
-    maybe empty pure =<< fmap dense readPrec
-
--- | Build a 'Dense' monetary value from a 'Rational' value.
---
--- For example, if you want to represent @USD 12.52316@, then you can use:
---
--- @
--- 'dense' (125316 % 10000)
--- @
---
--- This function returns 'Nothing' in case the given 'Rational' is 'infinity' or
--- 'notANumber'.
-dense :: Rational -> Maybe (Dense currency)
-dense = \r0 ->
-  if (infinity == r0 || notANumber == r0)
-  then Nothing else Just (Dense r0)
-{-# INLINE dense #-}
-
--- | 'Discrete' represents a discrete monetary value for a @currency@ expresed
--- as an integer amount of a particular @unit@. For example, with @currency ~
--- \"USD\"@ and @unit ~ \"cent\"@ you can represent United States Dollars to
--- their full extent.
---
--- @currency@ is usually a ISO-4217 currency code, but not necessarily.
---
--- Construct 'Discrete' values using 'fromInteger'.
---
--- For example, if you want to represent @GBP 21.05@, where the smallest
--- represetable unit for a GBP (United Kingdom Pound) is the /penny/, and 100
--- /pennies/ equal 1 GBP (i.e., @'Scale' \"GBP\" ~ '(100, 1)@), then you can
--- use:
---
--- @
--- 'fromInteger' 2105 :: Discrete \"GBP\" \"penny\"
--- @
---
--- Because @2015 / 100 == 20.15@.
-type Discrete (currency :: Symbol) (unit :: Symbol)
-  = Discrete' currency (Scale currency unit)
-
--- | 'Discrete'' represents a discrete monetary value for a @currency@ expresed
--- as an amount of @scale@, which is a rational number expressed as @(numerator,
--- denominator)@.
---
--- You'll be using 'Discrete' instead of 'Discrete'' most of the time, which
--- mentions the unit name (such as /cent/ or /centavo/) instead of explicitely
--- mentioning the unit scale.
-newtype Discrete' (currency :: Symbol) (scale :: (Nat, Nat))
-  = Discrete Integer
-
-deriving instance GoodScale scale => Eq (Discrete' currency scale)
-deriving instance GoodScale scale => Ord (Discrete' currency scale)
-deriving instance GoodScale scale => Enum (Discrete' currency scale)
-deriving instance GoodScale scale => Num (Discrete' currency scale)
-deriving instance GoodScale scale => Real (Discrete' currency scale)
-deriving instance GoodScale scale => Integral (Discrete' currency scale)
-deriving instance GoodScale scale => GHC.Generic (Discrete' currency scale)
-
-instance forall currency scale.
-  ( KnownSymbol currency, GoodScale scale
-  ) => Show (Discrete' currency scale) where
-  show = \d0@(Discrete i0) ->
-    let c = symbolVal (Proxy :: Proxy currency)
-    in concat [ "Discrete ", show c, " (", show (scale d0), ") ", show i0 ]
-
-instance forall currency scale.
-  ( KnownSymbol currency, GoodScale scale
-  ) => Read (Discrete' currency scale) where
-  readPrec = do
-    let c = symbolVal (Proxy :: Proxy currency)
-        s = scale (Proxy :: Proxy scale)
-    _ <- ReadPrec.lift (ReadP.string
-           ("Discrete " ++ show c ++ " (" ++ show s ++ ") ") )
-    Discrete <$> readPrec
-
-#if MIN_VERSION_base(4,9,0)
-instance
-  ( GHC.TypeError
-      (('GHC.Text "The ") 'GHC.:<>:
-       ('GHC.ShowType Discrete') 'GHC.:<>:
-       ('GHC.Text " type is deliberately not a ") 'GHC.:<>:
-       ('GHC.ShowType Fractional) 'GHC.:$$:
-       ('GHC.Text "instance. Convert the ") 'GHC.:<>:
-       ('GHC.ShowType Discrete') 'GHC.:<>:
-       ('GHC.Text " value to a ") 'GHC.:<>:
-       ('GHC.ShowType Dense) 'GHC.:$$:
-       ('GHC.Text "value and use the ") 'GHC.:<>:
-       ('GHC.ShowType Fractional) 'GHC.:<>:
-       ('GHC.Text " features on it instead."))
-  , GoodScale scale
-  ) => Fractional (Discrete' currency scale) where
-  fromRational = undefined
-  recip = undefined
-#endif
-
--- | Convert currency 'Discrete' monetary value into a 'Dense' monetary
--- value.
-fromDiscrete
-  :: GoodScale scale
-  => Discrete' currency scale
-  -> Dense currency -- ^
-fromDiscrete = \c@(Discrete i) -> Dense (fromInteger i / scale c)
-{-# INLINE fromDiscrete #-}
-
--- | Internal. Used to implement 'round', 'ceiling', 'floor' and 'truncate'.
-roundf
-  :: forall currency scale
-  .  GoodScale scale
-  => (Rational -> Integer) -- ^ 'Prelude.round', 'Prelude.ceiling' or similar.
-  -> Dense currency
-  -> (Discrete' currency scale, Maybe (Dense currency))
-roundf f = \c0 ->
-  let !r0 = toRational c0 :: Rational
-      !r1 = scale (Proxy :: Proxy scale)
-      !i2 = f (r0 * r1) :: Integer
-      !r2 = fromInteger i2 / r1 :: Rational
-      !ycrest | r0 == r2  = Nothing
-              | otherwise = Just (Dense (r0 - r2))
-      !d2 = Discrete i2
-  in (d2, ycrest)
-{-# INLINE roundf #-}
-
--- | Round a 'Dense' value @x@ to the nearest value fully representable in
--- its @currency@'s @unit@ 'Scale', which might be @x@ itself.
---
--- If @x@ is already fully representable in its @currency@'s @unit@ 'Scale',
--- then the following holds:
---
--- @
--- 'round' x == (x, 'Nothing')
--- @
---
--- Otherwise, if the nearest value to @x@ that is fully representable in its
--- @currency@'s @unit@ 'Scale' is greater than @x@, then the following holds:
---
--- @
--- 'round' == 'ceiling'
--- @
---
--- Otherwise, the nearest value to @x@ that is fully representable in its
--- @currency@'s @unit@ 'Scale' is smaller than @x@, and the following holds:
---
--- @
--- 'round' == 'floor'
--- @
---
--- Proof that 'round' doesn't lose money:
---
--- @
--- x == case 'round' x of
---        (y, 'Nothing') -> y
---        (y, 'Just' z)  -> y + z
--- @
-round
-  :: GoodScale scale
-  => Dense currency
-  -> (Discrete' currency scale, Maybe (Dense currency)) -- ^
-round = roundf Prelude.round
-{-# INLINE round #-}
-
--- | Round a 'Dense' value @x@ to the nearest value fully representable in
--- its @currency@'s @unit@ 'Scale' which is greater than @x@ or equal to @x@.
---
---
--- If @x@ is already fully representable in its @currency@'s @unit@ 'Scale',
--- then the following holds:
---
--- @
--- 'ceiling' x == (x, 'Nothing')
--- @
---
--- Otherwise, if @x@ is not representable in its @currency@'s @unit@ 'Scale',
--- then the following holds:
---
--- @
--- 'ceiling' x == (y, 'Just' z)
--- @
---
--- @
--- x /= y
--- @
---
--- @
--- z < 'zero'
--- @
---
--- Proof that 'ceiling' doesn't lose money:
---
--- @
--- x == case 'ceiling' x of
---        (y, 'Nothing') -> y
---        (y, 'Just' z)  -> y + z
--- @
-ceiling
-  :: GoodScale scale
-  => Dense currency
-  -> (Discrete' currency scale, Maybe (Dense currency)) -- ^
-ceiling = roundf Prelude.ceiling
-{-# INLINE ceiling #-}
-
--- | Round a 'Dense' value @x@ to the nearest value fully representable in
--- its @currency@'s @unit@ 'Scale' which is smaller than @x@ or equal to @x@.
---
---
--- If @x@ is already fully representable in its @currency@'s @unit@ 'Scale',
--- then the following holds:
---
--- @
--- 'floor' x == (x, 'Nothing')
--- @
---
--- Otherwise, if @x@ is not representable in its @currency@'s @unit@ 'Scale',
--- then the following holds:
---
--- @
--- 'floor' x == (y, 'Just' z)
--- @
---
--- @
--- x /= y
--- @
---
--- @
--- z > 'zero'
--- @
---
--- Proof that 'floor' doesn't lose money:
---
--- @
--- x == case 'floor' x of
---        (y, 'Nothing') -> y
---        (y, 'Just' z)  -> y + z
--- @
-floor
-  :: GoodScale scale
-  => Dense currency
-  -> (Discrete' currency scale, Maybe (Dense currency)) -- ^
-floor = roundf Prelude.floor
-{-# INLINE floor #-}
-
--- | Round a 'Dense' value @x@ to the nearest value between zero and
--- @x@ (inclusive) which is fully representable in its @currency@'s @unit@
--- 'Scale'.
---
--- If @x@ is already fully representable in its @currency@'s @unit@ 'Scale',
--- then the following holds:
---
--- @
--- 'truncate' x == (x, 'Nothing')
--- @
---
--- Otherwise, if @x@ is positive, then the following holds:
---
--- @
--- 'truncate' == 'floor'
--- @
---
--- Otherwise, if @x@ is negative, the following holds:
---
--- @
--- 'truncate' == 'ceiling'
--- @
---
--- Proof that 'truncate' doesn't lose money:
---
--- @
--- x == case 'truncate' x of
---        (y, 'Nothing') -> y
---        (y, 'Just' z)  -> y + z
--- @
-truncate
-  :: GoodScale scale
-  => Dense currency
-  -> (Discrete' currency scale, Maybe (Dense currency)) -- ^
-truncate = roundf Prelude.truncate
-{-# INLINE truncate #-}
-
---------------------------------------------------------------------------------
-
--- | @'Scale' currency unit@ is a rational number (expressed as @'(numerator,
--- denominator)@) indicating how many pieces of @unit@ fit in @currency@.
---
--- @currency@ is usually a ISO-4217 currency code, but not necessarily.
---
--- The 'Scale' will determine how to convert a 'Dense' value into a
--- 'Discrete' value and vice-versa.
---
--- For example, there are 100 USD cents in 1 USD, so the scale for this
--- relationship is:
---
--- @
--- type instance 'Scale' \"USD\" \"cent\" = '(100, 1)
--- @
---
--- As another example, there is 1 dollar in USD, so the scale for this
--- relationship is:
---
--- @
--- type instance 'Scale' \"USD\" \"dollar\" = '(1, 1)
--- @
---
--- When using 'Discrete' values to represent money, it will be impossible to
--- represent an amount of @currency@ smaller than @unit@. So, if you decide to
--- use @Scale \"USD\" \"dollar\"@ as your scale, you will not be able to
--- represent values such as USD 3.50 or USD 21.87, since they are not exact
--- multiples of a dollar.
---
--- If there exists a canonical smallest @unit@ that can fully represent the
--- currency, then an instance @'Scale' currency currency@ exists.
---
--- @
--- type instance 'Scale' \"USD\" \"USD\" = Scale \"USD\" \"cent\"
--- @
---
--- For some monetary values, such as precious metals, the smallest representable
--- unit is not obvious, since you can continue to split the precious metal many
--- times before it stops being a precious metal. Still, for practical purposes
--- we can make a sane arbitrary choice of smallest unit. For example, the base
--- unit for XAU (Gold) is the /troy ounce/, which is too big to be considered
--- the smallest unit, but we can arbitrarily choose the /milligrain/ as our
--- smallest unit, which is about as heavy as a single grain of table salt and
--- should be sufficiently precise for all monetary practical purposes. A /troy
--- ounce/ equals 480000 /milligrains/.
---
--- @
--- type instance 'Scale' \"XAG\" \"milligrain\" = '(480000, 1)
--- @
---
--- You can use other units such as /milligrams/ for measuring XAU, for example.
--- However, since the amount of /milligrams/ in a /troy ounce/ (31103.477) is
--- not integral, we need to use rational number to express it.
---
--- @
--- type instance 'Scale' \"XAU\" \"milligram\" = '(31103477, 1000)
--- @
---
--- If you try to obtain the 'Scale of a @currency@ without an obvious smallest
--- representable @unit@, like XAU, you will get a compile error.
-type family Scale (currency :: Symbol) (unit :: Symbol) :: (Nat, Nat)
-
-#if MIN_VERSION_base(4,9,0)
--- | A friendly 'GHC.TypeError' to use for a @currency@ that doesn't have a
--- canonical small unit.
-type family ErrScaleNonCanonical (currency :: Symbol) :: k where
-  ErrScaleNonCanonical c = GHC.TypeError
-    ( 'GHC.Text c 'GHC.:<>:
-      'GHC.Text " is not a currency with a canonical smallest unit," 'GHC.:$$:
-      'GHC.Text "be explicit about the currency unit you want to use." )
-#else
--- | Forbid a @currency@ that doesn't have a canonical small unit.
---
--- In GHC versions before 8.0 we can't provide a nice error message here, so we
--- simply set this to a value that will fail to satisfy 'GoodScale'. As a
--- consequence, trying to use this 'Scale' will result in a cryptic error saying
--- /«@Couldn't match type ‘'EQ’ with ‘'LT’@»/.
-type ErrScaleNonCanonical (currency :: Symbol) = '(0, 0)
-#endif
-
--- | Constraints to a scale (like the one returned by @'Scale' currency unit@)
--- expected to always be satisfied. In particular, the scale is always
--- guaranteed to be a positive rational number ('infinity' and 'notANumber' are
--- forbidden by 'GoodScale').
-type GoodScale (scale :: (Nat, Nat))
-   = ( CmpNat 0 (Fst scale) ~ 'LT
-     , CmpNat 0 (Snd scale) ~ 'LT
-     , KnownNat (Fst scale)
-     , KnownNat (Snd scale)
-     )
-
--- | If the specified @num@ and @den@ satisfy the expectations of 'GoodScale' at
--- the type level, then construct a proof for 'GoodScale'.
-mkGoodScale
-  :: forall num den
-  .  (KnownNat num, KnownNat den)
-  => Maybe (Dict (GoodScale '(num, den)))
-mkGoodScale =
-  let n = natVal (Proxy :: Proxy num)
-      d = natVal (Proxy :: Proxy den)
-  in if (n > 0) && (d > 0)
-     then Just (unsafeCoerce (Dict :: Dict ('LT ~ 'LT, 'LT ~ 'LT,
-                                            KnownNat num, KnownNat den)))
-     else Nothing
-{-# INLINE mkGoodScale #-}
-
--- | Term-level representation for the @currency@'s @unit@ 'Scale'.
---
--- For example, the 'Scale' for @\"USD\"@ in @\"cent\"@s is @100/1@.
---
--- The returned 'Rational' is statically guaranteed to be a positive number, and
--- to be different from both 'notANumber' and 'infinity'.
-scale :: forall proxy scale. GoodScale scale => proxy scale -> Rational -- ^
-scale = \_ ->
-   natVal (Proxy :: Proxy (Fst scale)) %
-   natVal (Proxy :: Proxy (Snd scale))
-{-# INLINE scale #-}
-
---------------------------------------------------------------------------------
-
--- | Exchange rate for converting monetary values of currency @src@ into
--- monetary values of currency @dst@ by multiplying for it.
---
--- For example, if in order to convert USD to GBP we have to multiply by 1.2345,
--- then we can represent this situaion using:
---
--- @
--- 'exchangeRate' (12345 % 10000) :: 'Maybe' ('ExchangeRate' \"USD\" \"GBP\")
--- @
-newtype ExchangeRate (src :: Symbol) (dst :: Symbol) = ExchangeRate Rational
-  deriving (Eq, Ord, GHC.Generic)
-
-instance forall src dst.
-  ( KnownSymbol src, KnownSymbol dst
-  ) => Show (ExchangeRate src dst) where
-  show = \(ExchangeRate r0) ->
-    let s = symbolVal (Proxy :: Proxy src)
-        d = symbolVal (Proxy :: Proxy dst)
-    in concat [ "ExchangeRate ", show s, " ", show d, " (", show r0, ")" ]
-
-instance forall src dst.
-  ( KnownSymbol src, KnownSymbol dst
-  ) => Read (ExchangeRate (src :: Symbol) (dst :: Symbol)) where
-  readPrec = do
-    let s = symbolVal (Proxy :: Proxy src)
-        d = symbolVal (Proxy :: Proxy dst)
-    _ <- ReadPrec.lift (ReadP.string
-            ("ExchangeRate " ++ show s ++ " " ++ show d ++ " "))
-    maybe empty pure =<< fmap exchangeRate readPrec
-
--- | Obtain a 'Rational' representation of the 'ExchangeRate'.
---
--- This 'Rational' is statically guaranteed to be greater than 0, different
--- from 'infinity' and different from 'notANumber'.
-fromExchangeRate :: ExchangeRate src dst -> Rational
-fromExchangeRate = \(ExchangeRate r0) -> r0
-{-# INLINE fromExchangeRate #-}
-
--- | Safely construct an 'ExchangeRate' from a 'Rational' number.
---
--- For construction to succeed, this 'Rational' must be greater than 0,
--- different from 'infinity' and different from 'notANumber'.
-exchangeRate :: Rational -> Maybe (ExchangeRate src dst)
-exchangeRate = \r0 ->
-  if (r0 <= 0 || infinity == r0 || notANumber == r0)
-  then Nothing else Just (ExchangeRate r0)
-{-# INLINE exchangeRate #-}
-
--- | Flip the direction of an 'ExchangeRate'.
---
--- Identity law:
---
--- @
--- 'flipExchangeRate' . 'flipExchangeRate'   ==  'id'
--- @
-flipExchangeRate :: ExchangeRate a b -> ExchangeRate b a
-flipExchangeRate = \(ExchangeRate x) -> ExchangeRate (1 / x)
-{-# INLINE flipExchangeRate #-}
-
--- | Apply the 'ExchangeRate' to the given @'Dense' src@ monetary value.
---
--- Identity law:
---
--- @
--- 'exchange' ('flipExchangeRate' x) . 'exchange' x  ==  'id'
--- @
---
--- Use the /Identity law/ for reasoning about going back and forth between @src@
--- and @dst@ in order to manage any leftovers that might not be representable as
--- a 'Discrete' monetary value of @src@.
-exchange :: ExchangeRate src dst -> Dense src -> Dense dst
-exchange = \(ExchangeRate r) -> \(Dense s) -> Dense (r * s)
-{-# INLINE exchange #-}
-
---------------------------------------------------------------------------------
--- DenseRep
-
--- | A monomorphic representation of 'Dense' that is easier to serialize and
--- deserialize than 'Dense' in case you don't know the type indexes involved.
-data DenseRep = DenseRep
-  { _denseRepCurrency          :: !String
-  , _denseRepAmountNumerator   :: !Integer
-  , _denseRepAmountDenominator :: !Integer  -- ^ Positive, non-zero.
-  } deriving (Eq, Show, GHC.Generic)
-
--- | WARNING: This instance does not compare monetary amounts, it just helps you
--- sort 'DenseRep' values in case you need to put them in a 'Data.Set.Set' or
--- similar.
-deriving instance Ord DenseRep
-
--- | Currency name.
-denseRepCurrency :: DenseRep -> String
-denseRepCurrency = _denseRepCurrency
-{-# INLINE denseRepCurrency #-}
-
--- | Currency unit amount.
-denseRepAmount :: DenseRep -> Rational
-denseRepAmount = \dr ->
-  denseRepAmountNumerator dr % denseRepAmountDenominator dr
-{-# INLINE denseRepAmount #-}
-
--- | Currency unit amount numerator.
-denseRepAmountNumerator :: DenseRep -> Integer
-denseRepAmountNumerator = _denseRepAmountNumerator
-{-# INLINE denseRepAmountNumerator #-}
-
--- | Currency unit amount denominator. Positive, non-zero.
-denseRepAmountDenominator :: DenseRep -> Integer
-denseRepAmountDenominator = _denseRepAmountDenominator
-{-# INLINE denseRepAmountDenominator #-}
-
--- | Internal. Build a 'DenseRep' from raw values.
-mkDenseRep
-  :: String -- ^ Currency.
-  -> Integer -- ^ Scale nominator.
-  -> Integer -- ^ Scale denominator (positive, non zero)
-  -> Maybe DenseRep
-mkDenseRep = \c n d -> case d > 0 of
-  False -> Nothing
-  True -> Just (DenseRep c n d)
-{-# INLINE mkDenseRep #-}
-
--- | Convert a 'Dense' to a 'DenseRep' for ease of serialization.
-denseRep :: KnownSymbol currency => Dense currency -> DenseRep
-denseRep = \(Dense r0 :: Dense currency) ->
-  let c = symbolVal (Proxy :: Proxy currency)
-  in DenseRep c (numerator r0) (denominator r0)
-{-# INLINE denseRep #-}
-
--- | Attempt to convert a 'DenseRep' to a 'Dense', provided you know the target
--- @currency@.
-fromDenseRep
-  :: forall currency
-  .  KnownSymbol currency
-  => DenseRep
-  -> Maybe (Dense currency)  -- ^
-fromDenseRep = \dr ->
-  case denseRepCurrency dr == symbolVal (Proxy :: Proxy currency) of
-     False -> Nothing
-     True -> Just (Dense (denseRepAmount dr))
-{-# INLINE fromDenseRep #-}
-
--- | Convert a 'DenseRep' to a 'Dense' without knowing the target @currency@.
---
--- Notice that @currency@ here can't leave its intended scope unless you can
--- prove equality with some other type at the outer scope, but in that case you
--- would be better off using 'fromDenseRep' directly.
-withDenseRep
-  :: DenseRep
-  -> (forall currency. KnownSymbol currency => Dense currency -> r)
-  -> r  -- ^
-withDenseRep dr = \f ->
-   case someSymbolVal (denseRepCurrency dr) of
-      SomeSymbol (Proxy :: Proxy currency) ->
-         f (Dense (denseRepAmount dr) :: Dense currency)
-{-# INLINE withDenseRep #-}
-
---------------------------------------------------------------------------------
--- DiscreteRep
-
--- | A monomorphic representation of 'Discrete' that is easier to serialize and
--- deserialize than 'Discrete' in case you don't know the type indexes involved.
-data DiscreteRep = DiscreteRep
-  { _discreteRepCurrency         :: !String   -- ^ Currency name.
-  , _discreteRepScaleNumerator   :: !Integer  -- ^ Positive, non-zero.
-  , _discreteRepScaleDenominator :: !Integer  -- ^ Positive, non-zero.
-  , _discreteRepAmount           :: !Integer  -- ^ Amount of unit.
-  } deriving (Eq, Show, GHC.Generic)
-
--- | WARNING: This instance does not compare monetary amounts, it just helps you
--- sort 'DiscreteRep' values in case you need to put them in a 'Data.Set.Set' or
--- similar.
-deriving instance Ord DiscreteRep
-
--- | Currency name.
-discreteRepCurrency :: DiscreteRep -> String
-discreteRepCurrency = _discreteRepCurrency
-{-# INLINE discreteRepCurrency #-}
-
--- | Positive, non-zero.
-discreteRepScale :: DiscreteRep -> Rational
-discreteRepScale = \dr ->
-  discreteRepScaleNumerator dr % discreteRepScaleDenominator dr
-{-# INLINE discreteRepScale #-}
-
--- | Positive, non-zero.
-discreteRepScaleNumerator :: DiscreteRep -> Integer
-discreteRepScaleNumerator = _discreteRepScaleNumerator
-{-# INLINE discreteRepScaleNumerator #-}
-
--- | Positive, non-zero.
-discreteRepScaleDenominator :: DiscreteRep -> Integer
-discreteRepScaleDenominator = _discreteRepScaleDenominator
-{-# INLINE discreteRepScaleDenominator #-}
-
--- | Amount of currency unit.
-discreteRepAmount :: DiscreteRep -> Integer
-discreteRepAmount = _discreteRepAmount
-{-# INLINE discreteRepAmount #-}
-
--- | Internal. Build a 'DiscreteRep' from raw values.
-mkDiscreteRep
-  :: String   -- ^ Currency name.
-  -> Integer  -- ^ Scale numerator. Positive, non-zero.
-  -> Integer  -- ^ Scale denominator. Positive, non-zero.
-  -> Integer  -- ^ Amount of unit.
-  -> Maybe DiscreteRep
-mkDiscreteRep = \c n d a -> case (n > 0) && (d > 0) of
-  False -> Nothing
-  True -> Just (DiscreteRep c n d a)
-{-# INLINE mkDiscreteRep #-}
-
--- | Convert a 'Discrete' to a 'DiscreteRep' for ease of serialization.
-discreteRep
-  :: (KnownSymbol currency, GoodScale scale)
-  => Discrete' currency scale
-  -> DiscreteRep -- ^
-discreteRep = \(Discrete i0 :: Discrete' currency scale) ->
-  let c = symbolVal (Proxy :: Proxy currency)
-      n = natVal (Proxy :: Proxy (Fst scale))
-      d = natVal (Proxy :: Proxy (Snd scale))
-  in DiscreteRep c n d i0
-{-# INLINE discreteRep #-}
-
--- | Attempt to convert a 'DiscreteRep' to a 'Discrete', provided you know the
--- target @currency@ and @unit@.
-fromDiscreteRep
-  :: forall currency scale
-  .  (KnownSymbol currency, GoodScale scale)
-  => DiscreteRep
-  -> Maybe (Discrete' currency scale)  -- ^
-fromDiscreteRep = \dr ->
-   if (discreteRepCurrency dr == symbolVal (Proxy :: Proxy currency)) &&
-      (discreteRepScaleNumerator dr == natVal (Proxy :: Proxy (Fst scale))) &&
-      (discreteRepScaleDenominator dr == natVal (Proxy :: Proxy (Snd scale)))
-   then Just (Discrete (discreteRepAmount dr))
-   else Nothing
-{-# INLINE fromDiscreteRep #-}
-
--- | Convert a 'DiscreteRep' to a 'Discrete' without knowing the target
--- @currency@ and @unit@.
---
--- Notice that @currency@ and @unit@ here can't leave its intended scope unless
--- you can prove equality with some other type at the outer scope, but in that
--- case you would be better off using 'fromDiscreteRep' directly.
---
--- Notice that you may need to add an explicit type to the result of this
--- function in order to keep the compiler happy.
-withDiscreteRep
-  :: forall r
-  .  DiscreteRep
-  -> ( forall currency scale.
-         ( KnownSymbol currency
-         , GoodScale scale
-         ) => Discrete' currency scale
-           -> r )
-  -> r  -- ^
-withDiscreteRep dr = \f ->
-  case someSymbolVal (discreteRepCurrency dr) of
-    SomeSymbol (Proxy :: Proxy currency) ->
-      case someNatVal (discreteRepScaleNumerator dr) of
-        Nothing -> error "withDiscreteRep: impossible: numerator < 0"
-        Just (SomeNat (Proxy :: Proxy num)) ->
-          case someNatVal (discreteRepScaleDenominator dr) of
-            Nothing -> error "withDiscreteRep: impossible: denominator < 0"
-            Just (SomeNat (Proxy :: Proxy den)) ->
-              case mkGoodScale of
-                Nothing -> error "withDiscreteRep: impossible: mkGoodScale"
-                Just (Dict :: Dict (GoodScale '(num, den))) ->
-                  f (Discrete (discreteRepAmount dr)
-                       :: Discrete' currency '(num, den))
-{-# INLINABLE withDiscreteRep #-}
-
---------------------------------------------------------------------------------
--- ExchangeRateRep
-
--- | A monomorphic representation of 'ExchangeRate' that is easier to serialize
--- and deserialize than 'ExchangeRate' in case you don't know the type indexes
--- involved.
-data ExchangeRateRep = ExchangeRateRep
-  { _exchangeRateRepSrcCurrency     :: !String
-  , _exchangeRateRepDstCurrency     :: !String
-  , _exchangeRateRepRateNumerator   :: !Integer  -- ^ Positive, non-zero.
-  , _exchangeRateRepRateDenominator :: !Integer  -- ^ Positive, non-zero.
-  } deriving (Eq, Show, GHC.Generic)
-
--- | WARNING: This instance does not compare monetary amounts, it just helps you
--- sort 'ExchangeRateRep' values in case you need to put them in a
--- 'Data.Set.Set' or similar.
-deriving instance Ord ExchangeRateRep
-
--- | Source currency name.
-exchangeRateRepSrcCurrency :: ExchangeRateRep -> String
-exchangeRateRepSrcCurrency = _exchangeRateRepSrcCurrency
-{-# INLINE exchangeRateRepSrcCurrency #-}
-
--- | Destination currency name.
-exchangeRateRepDstCurrency :: ExchangeRateRep -> String
-exchangeRateRepDstCurrency = _exchangeRateRepDstCurrency
-{-# INLINE exchangeRateRepDstCurrency #-}
-
--- | Exchange rate. Positive, non-zero.
-exchangeRateRepRate :: ExchangeRateRep -> Rational
-exchangeRateRepRate = \x ->
-  exchangeRateRepRateNumerator x % _exchangeRateRepRateDenominator x
-{-# INLINE exchangeRateRepRate #-}
-
--- | Exchange rate numerator. Positive, non-zero.
-exchangeRateRepRateNumerator :: ExchangeRateRep -> Integer
-exchangeRateRepRateNumerator = _exchangeRateRepRateNumerator
-{-# INLINE exchangeRateRepRateNumerator #-}
-
--- | Exchange rate denominator. Positive, non-zero.
-exchangeRateRepRateDenominator :: ExchangeRateRep -> Integer
-exchangeRateRepRateDenominator = _exchangeRateRepRateDenominator
-{-# INLINE exchangeRateRepRateDenominator #-}
-
--- | Internal. Build a 'ExchangeRateRep' from raw values.
-mkExchangeRateRep
-  :: String   -- ^ Source currency name.
-  -> String   -- ^ Destination currency name.
-  -> Integer  -- ^ Exchange rate numerator. Positive, non-zero.
-  -> Integer  -- ^ Exchange rate denominator. Positive, non-zero.
-  -> Maybe ExchangeRateRep
-mkExchangeRateRep = \src dst n d -> case (n > 0) && (d > 0) of
-  False -> Nothing
-  True -> Just (ExchangeRateRep src dst n d)
-{-# INLINE mkExchangeRateRep #-}
-
--- | Convert a 'ExchangeRate' to a 'DiscreteRep' for ease of serialization.
-exchangeRateRep
-  :: (KnownSymbol src, KnownSymbol dst)
-  => ExchangeRate src dst
-  -> ExchangeRateRep -- ^
-exchangeRateRep = \(ExchangeRate r0 :: ExchangeRate src dst) ->
-  let src = symbolVal (Proxy :: Proxy src)
-      dst = symbolVal (Proxy :: Proxy dst)
-  in ExchangeRateRep src dst (numerator r0) (denominator r0)
-{-# INLINE exchangeRateRep #-}
-
--- | Attempt to convert a 'ExchangeRateRep' to a 'ExchangeRate', provided you
--- know the target @src@ and @dst@ types.
-fromExchangeRateRep
-  :: forall src dst
-  .  (KnownSymbol src, KnownSymbol dst)
-  => ExchangeRateRep
-  -> Maybe (ExchangeRate src dst)  -- ^
-fromExchangeRateRep = \x ->
-   if (exchangeRateRepSrcCurrency x == symbolVal (Proxy :: Proxy src)) &&
-      (exchangeRateRepDstCurrency x == symbolVal (Proxy :: Proxy dst))
-   then Just (ExchangeRate (exchangeRateRepRate x))
-   else Nothing
-{-# INLINE fromExchangeRateRep #-}
-
--- | Convert a 'ExchangeRateRep' to a 'ExchangeRate' without knowing the target
--- @currency@ and @unit@.
---
--- Notice that @src@ and @dst@ here can't leave its intended scope unless
--- you can prove equality with some other type at the outer scope, but in that
--- case you would be better off using 'fromExchangeRateRep' directly.
-withExchangeRateRep
-  :: ExchangeRateRep
-  -> ( forall src dst.
-         ( KnownSymbol src
-         , KnownSymbol dst
-         ) => ExchangeRate src dst
-           -> r )
-  -> r  -- ^
-withExchangeRateRep x = \f ->
-  case someSymbolVal (exchangeRateRepSrcCurrency x) of
-    SomeSymbol (Proxy :: Proxy src) ->
-      case someSymbolVal (exchangeRateRepDstCurrency x) of
-        SomeSymbol (Proxy :: Proxy dst) ->
-          f (ExchangeRate (exchangeRateRepRate x) :: ExchangeRate src dst)
-{-# INLINABLE withExchangeRateRep #-}
-
---------------------------------------------------------------------------------
--- Miscellaneous
-
-type family Fst (ab :: (ka, kb)) :: ka where Fst '(a,b) = a
-type family Snd (ab :: (ka, kb)) :: ka where Snd '(a,b) = b
-
---------------------------------------------------------------------------------
--- Extra instances: hashable
-#ifdef VERSION_hashable
-instance Hashable (Dense currency)
-instance Hashable DenseRep
-instance GoodScale scale => Hashable (Discrete' currency scale)
-instance Hashable DiscreteRep
-instance Hashable (ExchangeRate src dst)
-instance Hashable ExchangeRateRep
-#endif
-
---------------------------------------------------------------------------------
--- Extra instances: deepseq
-#ifdef VERSION_deepseq
-instance NFData (Dense currency)
-instance NFData DenseRep
-instance GoodScale scale => NFData (Discrete' currency scale)
-instance NFData DiscreteRep
-instance NFData (ExchangeRate src dst)
-instance NFData ExchangeRateRep
-#endif
-
---------------------------------------------------------------------------------
--- Extra instances: cereal
-#ifdef VERSION_cereal
--- | Compatible with 'DenseRep'.
-instance (KnownSymbol currency) => Cereal.Serialize (Dense currency) where
-  put = Cereal.put . denseRep
-  get = maybe empty pure =<< fmap fromDenseRep Cereal.get
--- | Compatible with 'DiscreteRep'.
-instance
-  ( KnownSymbol currency, GoodScale scale
-  ) => Cereal.Serialize (Discrete' currency scale) where
-  put = Cereal.put . discreteRep
-  get = maybe empty pure =<< fmap fromDiscreteRep Cereal.get
--- | Compatible with 'ExchangeRateRep'.
-instance
-  ( KnownSymbol src, KnownSymbol dst
-  ) => Cereal.Serialize (ExchangeRate src dst) where
-  put = Cereal.put . exchangeRateRep
-  get = maybe empty pure =<< fmap fromExchangeRateRep Cereal.get
--- | Compatible with 'Dense'.
-instance Cereal.Serialize DenseRep where
-  put = \(DenseRep c n d) -> Cereal.put c >> Cereal.put n >> Cereal.put d
-  get = maybe empty pure =<< mkDenseRep
-    <$> Cereal.get <*> Cereal.get <*> Cereal.get
--- | Compatible with 'Discrete'.
-instance Cereal.Serialize DiscreteRep where
-  put = \(DiscreteRep c n d a) ->
-    Cereal.put c >> Cereal.put n >> Cereal.put d >> Cereal.put a
-  get = maybe empty pure =<< mkDiscreteRep
-    <$> Cereal.get <*> Cereal.get <*> Cereal.get <*> Cereal.get
--- | Compatible with 'ExchangeRate'.
-instance Cereal.Serialize ExchangeRateRep where
-  put = \(ExchangeRateRep src dst n d) ->
-    Cereal.put src >> Cereal.put dst >> Cereal.put n >> Cereal.put d
-  get = maybe empty pure =<< mkExchangeRateRep
-    <$> Cereal.get <*> Cereal.get <*> Cereal.get <*> Cereal.get
-#endif
-
---------------------------------------------------------------------------------
--- Extra instances: binary
-#ifdef VERSION_binary
--- | Compatible with 'DenseRep'.
-instance (KnownSymbol currency) => Binary.Binary (Dense currency) where
-  put = Binary.put . denseRep
-  get = maybe empty pure =<< fmap fromDenseRep Binary.get
--- | Compatible with 'DiscreteRep'.
-instance
-  ( KnownSymbol currency, GoodScale scale
-  ) => Binary.Binary (Discrete' currency scale) where
-  put = Binary.put . discreteRep
-  get = maybe empty pure =<< fmap fromDiscreteRep Binary.get
--- | Compatible with 'ExchangeRateRep'.
-instance
-  ( KnownSymbol src, KnownSymbol dst
-  ) => Binary.Binary (ExchangeRate src dst) where
-  put = Binary.put . exchangeRateRep
-  get = maybe empty pure =<< fmap fromExchangeRateRep Binary.get
--- | Compatible with 'Dense'.
-instance Binary.Binary DenseRep where
-  put = \(DenseRep c n d) -> Binary.put c >> Binary.put n >> Binary.put d
-  get = maybe empty pure =<< mkDenseRep
-    <$> Binary.get <*> Binary.get <*> Binary.get
--- | Compatible with 'Discrete'.
-instance Binary.Binary DiscreteRep where
-  put = \(DiscreteRep c n d a) ->
-    Binary.put c >> Binary.put n >> Binary.put d >> Binary.put a
-  get = maybe empty pure =<< mkDiscreteRep
-    <$> Binary.get <*> Binary.get <*> Binary.get <*> Binary.get
--- | Compatible with 'ExchangeRate'.
-instance Binary.Binary ExchangeRateRep where
-  put = \(ExchangeRateRep src dst n d) ->
-    Binary.put src >> Binary.put dst >> Binary.put n >> Binary.put d
-  get = maybe empty pure =<< mkExchangeRateRep
-    <$> Binary.get <*> Binary.get <*> Binary.get <*> Binary.get
-#endif
-
---------------------------------------------------------------------------------
--- Extra instances: aeson
-#ifdef VERSION_aeson
--- | Compatible with 'DenseRep'
-instance KnownSymbol currency => Ae.ToJSON (Dense currency) where
-  toJSON = Ae.toJSON . denseRep
--- | Compatible with 'DenseRep'
-instance KnownSymbol currency => Ae.FromJSON (Dense currency) where
-  parseJSON = maybe empty pure <=< fmap fromDenseRep . Ae.parseJSON
--- | Compatible with 'Dense'
-instance Ae.ToJSON DenseRep where
-  toJSON = \(DenseRep c n d) -> Ae.toJSON ("Dense", c, n, d)
--- | Compatible with 'Dense'
-instance Ae.FromJSON DenseRep where
-  parseJSON = \v -> do
-    ("Dense", c, n, d) <- Ae.parseJSON v
-    maybe empty pure (mkDenseRep c n d)
--- | Compatible with 'DiscreteRep'
-instance
-  ( KnownSymbol currency, GoodScale scale
-  ) => Ae.ToJSON (Discrete' currency scale) where
-  toJSON = Ae.toJSON . discreteRep
--- | Compatible with 'DiscreteRep'
-instance
-  ( KnownSymbol currency, GoodScale scale
-  ) => Ae.FromJSON (Discrete' currency scale) where
-  parseJSON = maybe empty pure <=< fmap fromDiscreteRep . Ae.parseJSON
--- | Compatible with 'Discrete''
-instance Ae.ToJSON DiscreteRep where
-  toJSON = \(DiscreteRep c n d a) -> Ae.toJSON ("Discrete", c, n, d, a)
--- | Compatible with 'Discrete''
-instance Ae.FromJSON DiscreteRep where
-  parseJSON = \v -> do
-    ("Discrete", c, n, d, a) <- Ae.parseJSON v
-    maybe empty pure (mkDiscreteRep c n d a)
--- | Compatible with 'ExchangeRateRep'
-instance
-  ( KnownSymbol src, KnownSymbol dst
-  ) => Ae.ToJSON (ExchangeRate src dst) where
-  toJSON = Ae.toJSON . exchangeRateRep
--- | Compatible with 'ExchangeRateRep'
-instance
-  ( KnownSymbol src, KnownSymbol dst
-  ) => Ae.FromJSON (ExchangeRate src dst) where
-  parseJSON = maybe empty pure <=< fmap fromExchangeRateRep . Ae.parseJSON
--- | Compatible with 'ExchangeRate'
-instance Ae.ToJSON ExchangeRateRep where
-  toJSON = \(ExchangeRateRep src dst n d) ->
-    Ae.toJSON ("ExchangeRate", src, dst, n, d)
--- | Compatible with 'ExchangeRate'
-instance Ae.FromJSON ExchangeRateRep where
-  parseJSON = \v -> do
-    ("ExchangeRate", src, dst, n, d) <- Ae.parseJSON v
-    maybe empty pure (mkExchangeRateRep src dst n d)
-#endif
-
---------------------------------------------------------------------------------
--- Extra instances: store
-#ifdef VERSION_store
--- | Compatible with 'DenseRep'.
-instance (KnownSymbol currency) => Store.Store (Dense currency) where
-  size = storeContramapSize denseRep Store.size
-  poke = Store.poke . denseRep
-  peek = maybe (fail "peek") pure =<< fmap fromDenseRep Store.peek
--- | Compatible with 'Dense'.
-instance Store.Store DenseRep where
-  poke = \(DenseRep c n d) -> Store.poke c >> Store.poke n >> Store.poke d
-  peek = maybe (fail "peek") pure =<< do
-    mkDenseRep <$> Store.peek <*> Store.peek <*> Store.peek
-
--- | Compatible with 'DiscreteRep'.
-instance
-  ( KnownSymbol currency, GoodScale scale
-  ) => Store.Store (Discrete' currency scale) where
-  size = storeContramapSize discreteRep Store.size
-  poke = Store.poke . discreteRep
-  peek = maybe (fail "peek") pure =<< fmap fromDiscreteRep Store.peek
--- | Compatible with 'Discrete''.
-instance Store.Store DiscreteRep where
-  poke = \(DiscreteRep c n d a) ->
-    Store.poke c >> Store.poke n >> Store.poke d >> Store.poke a
-  peek = maybe (fail "peek") pure =<< do
-    mkDiscreteRep <$> Store.peek <*> Store.peek <*> Store.peek <*> Store.peek
--- | Compatible with 'ExchangeRateRep'.
-instance
-  ( KnownSymbol src, KnownSymbol dst
-  ) => Store.Store (ExchangeRate src dst) where
-  size = storeContramapSize exchangeRateRep Store.size
-  poke = Store.poke . exchangeRateRep
-  peek = maybe (fail "peek") pure =<< fmap fromExchangeRateRep Store.peek
--- | Compatible with 'ExchangeRate'.
-instance Store.Store ExchangeRateRep where
-  poke = \(ExchangeRateRep src dst n d) ->
-    Store.poke src >> Store.poke dst >> Store.poke n >> Store.poke d
-  peek = maybe (fail "peek") pure =<< mkExchangeRateRep
-    <$> Store.peek <*> Store.peek <*> Store.peek <*> Store.peek
-
-storeContramapSize :: (a -> b) -> Store.Size b -> Store.Size a
-storeContramapSize f = \case
-  Store.VarSize g -> Store.VarSize (g . f)
-  Store.ConstSize x -> Store.ConstSize x
-{-# INLINE storeContramapSize #-}
-#endif
diff --git a/src/Money.hs b/src/Money.hs
new file mode 100644
--- /dev/null
+++ b/src/Money.hs
@@ -0,0 +1,793 @@
+{-# LANGUAGE CPP #-}
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE TypeFamilies #-}
+{-# LANGUAGE UndecidableInstances #-}
+
+-- | Import this module qualified as follows:
+--
+-- @
+-- import qualified Money
+-- @
+--
+-- Note: This module exports many well-known currencies out-of-the-box, but
+-- you are not limited to the currencies mentioned here. You can simply create
+-- a new 'I.Scale' instance, and /voilà/. If you want to add a new currency to the
+-- out-of-the-box offer, please request so in
+-- https://github.com/k0001/safe-money/issues and the authors will see to it.
+module Money
+ ( -- * Dense monetary values
+   I.Dense
+ , I.dense
+   -- * Discrete monetary values
+ , I.Discrete
+ , I.Discrete'
+ , I.fromDiscrete
+ , I.round
+ , I.ceiling
+ , I.floor
+ , I.truncate
+   -- * Currency scales
+ , I.Scale
+ , I.GoodScale
+ , I.scale
+   -- * Currency exchange
+ , I.ExchangeRate
+ , I.exchangeRate
+ , I.fromExchangeRate
+ , I.flipExchangeRate
+ , I.exchange
+   -- * Serializable representations
+ , I.DenseRep
+ , I.toDenseRep
+ , I.mkDenseRep
+ , I.fromDenseRep
+ , I.withDenseRep
+ , I.denseRepCurrency
+ , I.denseRepAmount
+ , I.denseRepAmountNumerator
+ , I.denseRepAmountDenominator
+ , I.DiscreteRep
+ , I.toDiscreteRep
+ , I.mkDiscreteRep
+ , I.fromDiscreteRep
+ , I.withDiscreteRep
+ , I.discreteRepCurrency
+ , I.discreteRepScale
+ , I.discreteRepScaleNumerator
+ , I.discreteRepScaleDenominator
+ , I.discreteRepAmount
+ , I.ExchangeRateRep
+ , I.toExchangeRateRep
+ , I.mkExchangeRateRep
+ , I.fromExchangeRateRep
+ , I.withExchangeRateRep
+ , I.exchangeRateRepSrcCurrency
+ , I.exchangeRateRepDstCurrency
+ , I.exchangeRateRepRate
+ , I.exchangeRateRepRateNumerator
+ , I.exchangeRateRepRateDenominator
+ ) where
+
+import qualified Money.Internal as I
+
+--------------------------------------------------------------------------------
+-- Currency scales
+
+-- | United Arab Emirates dirham
+type instance I.Scale "AED" "AED" = '(100, 1)
+type instance I.Scale "AED" "dirham" = '(1, 1)
+type instance I.Scale "AED" "fils" = '(100, 1)
+-- | Afghan afghani
+type instance I.Scale "AFN" "AFN" = '(100, 1)
+type instance I.Scale "AFN" "afghani" = '(1, 1)
+type instance I.Scale "AFN" "pul" = '(100, 1)
+-- | Albanian lek
+type instance I.Scale "ALL" "ALL" = '(100, 1)
+type instance I.Scale "ALL" "lek" = '(1, 1)
+type instance I.Scale "ALL" "qindarke" = '(100, 1)
+-- | Armenian dram
+type instance I.Scale "AMD" "AMD" = '(100, 1)
+type instance I.Scale "AMD" "dram" = '(1, 1)
+type instance I.Scale "AMD" "luma" = '(100, 1)
+-- | Netherlands Antillean guilder
+type instance I.Scale "ANG" "ANG" = '(100, 1)
+type instance I.Scale "ANG" "guilder" = '(1, 1)
+type instance I.Scale "ANG" "cent" = '(100, 1)
+-- | Angolan kwanza
+type instance I.Scale "AOA" "AOA" = '(100, 1)
+type instance I.Scale "AOA" "kwanza" = '(1, 1)
+type instance I.Scale "AOA" "centimo" = '(100, 1)
+-- | Argentine peso
+type instance I.Scale "ARS" "ARS" = '(100, 1)
+type instance I.Scale "ARS" "peso" = '(1, 1)
+type instance I.Scale "ARS" "centavo" = '(100, 1)
+-- | Australian dollar
+type instance I.Scale "AUD" "AUD" = '(100, 1)
+type instance I.Scale "AUD" "dollar" = '(1, 1)
+type instance I.Scale "AUD" "cent" = '(100, 1)
+-- | Aruban florin
+type instance I.Scale "AWG" "AWG" = '(100, 1)
+type instance I.Scale "AWG" "florin" = '(1, 1)
+type instance I.Scale "AWG" "cent" = '(100, 1)
+-- | Azerbaijani manat
+type instance I.Scale "AZN" "AZN" = '(100, 1)
+type instance I.Scale "AZN" "manat" = '(1, 1)
+type instance I.Scale "AZN" "qapik" = '(100, 1)
+-- | Bosnia and Herzegovina convertible mark
+type instance I.Scale "BAM" "BAM" = '(100, 1)
+type instance I.Scale "BAM" "mark" = '(1, 1)
+type instance I.Scale "BAM" "fening" = '(100, 1)
+-- | Barbadian dollar
+type instance I.Scale "BBD" "BBD" = '(100, 1)
+type instance I.Scale "BBD" "dollar" = '(1, 1)
+type instance I.Scale "BBD" "cent" = '(100, 1)
+-- | Bangladeshi taka
+type instance I.Scale "BDT" "BDT" = '(100, 1)
+type instance I.Scale "BDT" "taka" = '(1, 1)
+type instance I.Scale "BDT" "paisa" = '(100, 1)
+-- | Bulgarian lev
+type instance I.Scale "BGN" "BGN" = '(100, 1)
+type instance I.Scale "BGN" "lev" = '(1, 1)
+type instance I.Scale "BGN" "stotinka" = '(100, 1)
+-- | Bahraini dinar
+type instance I.Scale "BHD" "BHD" = '(1000, 1)
+type instance I.Scale "BHD" "dinar" = '(1, 1)
+type instance I.Scale "BHD" "fils" = '(1000, 1)
+-- | Burundi franc
+type instance I.Scale "BIF" "BIF" = '(100, 1)
+type instance I.Scale "BIF" "franc" = '(1, 1)
+type instance I.Scale "BIF" "centime" = '(100, 1)
+-- | Bermudian dollar
+type instance I.Scale "BMD" "BMD" = '(100, 1)
+type instance I.Scale "BMD" "dollar" = '(1, 1)
+type instance I.Scale "BMD" "cent" = '(100, 1)
+-- | Brunei dollar
+type instance I.Scale "BND" "BND" = '(100, 1)
+type instance I.Scale "BND" "dollar" = '(1, 1)
+type instance I.Scale "BND" "sen" = '(100, 1)
+-- | Bolivian boliviano
+type instance I.Scale "BOB" "BOB" = '(100, 1)
+type instance I.Scale "BOB" "boliviano" = '(1, 1)
+type instance I.Scale "BOB" "centavo" = '(100, 1)
+-- | Bolivian Mvdol
+type instance I.Scale "BOV" "BOV" = '(100, 1)
+-- | Brazilian real
+type instance I.Scale "BRL" "BRL" = '(100, 1)
+type instance I.Scale "BRL" "real" = '(1, 1)
+type instance I.Scale "BRL" "centavo" = '(100, 1)
+-- | Bahamian dollar
+type instance I.Scale "BSD" "BSD" = '(100, 1)
+type instance I.Scale "BSD" "dollar" = '(1, 1)
+type instance I.Scale "BSD" "cent" = '(1, 1)
+-- | Bhutanese ngultrum
+type instance I.Scale "BTN" "BTN" = '(100, 1)
+type instance I.Scale "BTN" "ngultrum" = '(1, 1)
+type instance I.Scale "BTN" "chetrum" = '(100, 1)
+-- | Botswana pula
+type instance I.Scale "BWP" "BWP" = '(100, 1)
+type instance I.Scale "BWP" "pula" = '(1, 1)
+type instance I.Scale "BWP" "thebe" = '(100, 1)
+-- | Belarusian ruble
+type instance I.Scale "BYN" "BYN" = '(100, 1)
+-- | Belarusian ruble
+type instance I.Scale "BYR" "BYR" = '(100, 1)
+type instance I.Scale "BYR" "ruble" = '(1, 1)
+type instance I.Scale "BYR" "kapyeyka" = '(100, 1)
+-- | Belize dollar
+type instance I.Scale "BZD" "BZD" = '(100, 1)
+type instance I.Scale "BZD" "dollar" = '(1, 1)
+type instance I.Scale "BZD" "cent" = '(100, 1)
+-- | Canadian dollar
+type instance I.Scale "CAD" "CAD" = '(100, 1)
+type instance I.Scale "CAD" "dollar" = '(1, 1)
+type instance I.Scale "CAD" "cent" = '(100, 1)
+-- | Congolese franc
+type instance I.Scale "CDF" "CDF" = '(100, 1)
+type instance I.Scale "CDF" "franc" = '(1, 1)
+type instance I.Scale "CDF" "centime" = '(100, 1)
+-- | WIR euro
+type instance I.Scale "CHE" "CHE" = '(100, 1)
+-- | Swiss franc
+type instance I.Scale "CHF" "CHF" = '(100, 1)
+type instance I.Scale "CHF" "franc" = '(1, 1)
+type instance I.Scale "CHF" "rappen" = '(100, 1)
+-- | WIR franc
+type instance I.Scale "CHW" "CHW" = '(100, 1)
+-- | Chilean unidad de fomento
+type instance I.Scale "CLF" "CLF" = '(100, 1)
+-- | Chilean peso
+type instance I.Scale "CLP" "CLP" = '(100, 1)
+type instance I.Scale "CLP" "peso" = '(1, 1)
+type instance I.Scale "CLP" "centavo" = '(100, 1)
+-- | Chinese Renminbi
+type instance I.Scale "CNY" "CNY" = '(100, 1)
+type instance I.Scale "CNY" "yuan" = '(1, 1)
+type instance I.Scale "CNY" "fen" = '(100, 1)
+-- | Colombian peso
+type instance I.Scale "COP" "COP" = '(100, 1)
+type instance I.Scale "COP" "peso" = '(1, 1)
+type instance I.Scale "COP" "centavo" = '(100, 1)
+-- | Colombian unidad de valor real
+type instance I.Scale "COU" "COU" = '(100, 1)
+-- | Costa Rican colon
+type instance I.Scale "CRC" "CRC" = '(100, 1)
+type instance I.Scale "CRC" "colon" = '(1, 1)
+type instance I.Scale "CRC" "centimo" = '(100, 1)
+-- | Cuban peso convertible
+type instance I.Scale "CUC" "CUC" = '(100, 1)
+type instance I.Scale "CUC" "peso" = '(1, 1)
+type instance I.Scale "CUC" "centavo" = '(100, 1)
+-- | Cuban peso
+type instance I.Scale "CUP" "CUP" = '(100, 1)
+type instance I.Scale "CUP" "peso" = '(1, 1)
+type instance I.Scale "CUP" "centavo" = '(100, 1)
+-- | Cape Verdean escudo
+type instance I.Scale "CVE" "CVE" = '(100, 1)
+type instance I.Scale "CVE" "escudo" = '(1, 1)
+type instance I.Scale "CVE" "centavo" = '(100, 1)
+-- | Czech koruna
+type instance I.Scale "CZK" "CZK" = '(100, 1)
+type instance I.Scale "CZK" "koruna" = '(1, 1)
+type instance I.Scale "CZK" "haler" = '(100, 1)
+-- | Djiboutian franc
+type instance I.Scale "DJF" "DJF" = '(100, 1)
+type instance I.Scale "DJF" "franc" = '(1, 1)
+type instance I.Scale "DJF" "centime" = '(100, 1)
+-- | Danish krone
+type instance I.Scale "DKK" "DKK" = '(100, 1)
+type instance I.Scale "DKK" "krone" = '(1, 1)
+type instance I.Scale "DKK" "ore" = '(100, 1)
+-- | Dominican peso
+type instance I.Scale "DOP" "DOP" = '(100, 1)
+type instance I.Scale "DOP" "peso" = '(1, 1)
+type instance I.Scale "DOP" "centavo" = '(100, 1)
+-- | Algerian dinar
+type instance I.Scale "DZD" "DZD" = '(100, 1)
+type instance I.Scale "DZD" "dinar" = '(1, 1)
+type instance I.Scale "DZD" "santeem" = '(100, 1)
+-- | Egyptian pound
+type instance I.Scale "EGP" "EGP" = '(100, 1)
+type instance I.Scale "EGP" "pound" = '(1, 1)
+type instance I.Scale "EGP" "piastre" = '(100, 1)
+-- | Eritrean nakfa
+type instance I.Scale "ERN" "ERN" = '(100, 1)
+type instance I.Scale "ERN" "nafka" = '(1, 1)
+type instance I.Scale "ERN" "cent" = '(100, 1)
+-- | Ethiopian birr
+type instance I.Scale "ETB" "ETB" = '(100, 1)
+type instance I.Scale "ETB" "birr" = '(1, 1)
+type instance I.Scale "ETB" "santim" = '(100, 1)
+-- | European euro
+type instance I.Scale "EUR" "EUR" = '(100, 1)
+type instance I.Scale "EUR" "euro" = '(1, 1)
+type instance I.Scale "EUR" "cent" = '(100, 1)
+-- | Fijian dollar
+type instance I.Scale "FJD" "FJD" = '(100, 1)
+-- | Falkland Islands pound
+type instance I.Scale "FKP" "FKP" = '(100, 1)
+type instance I.Scale "FKP" "pound" = '(1, 1)
+type instance I.Scale "FKP" "penny" = '(100, 1)
+-- | Pound sterling
+type instance I.Scale "GBP" "GBP" = '(100, 1)
+type instance I.Scale "GBP" "pound" = '(1, 1)
+type instance I.Scale "GBP" "penny" = '(100, 1)
+-- | Georgian lari
+type instance I.Scale "GEL" "GEL" = '(100, 1)
+type instance I.Scale "GEL" "lari" = '(1, 1)
+type instance I.Scale "GEL" "tetri" = '(100, 1)
+-- | Ghanaian cedi
+type instance I.Scale "GHS" "GHS" = '(100, 1)
+type instance I.Scale "GHS" "cedi" = '(1, 1)
+type instance I.Scale "GHS" "pesewa" = '(100, 1)
+-- | Gibraltar pound
+type instance I.Scale "GIP" "GIP" = '(100, 1)
+type instance I.Scale "GIP" "pound" = '(1, 1)
+type instance I.Scale "GIP" "penny" = '(100, 1)
+-- | Gambian dalasi
+type instance I.Scale "GMD" "GMD" = '(100, 1)
+type instance I.Scale "GMD" "dalasi" = '(1, 1)
+type instance I.Scale "GMD" "butut" = '(100, 1)
+-- | Guinean franc
+type instance I.Scale "GNF" "GNF" = '(100, 1)
+type instance I.Scale "GNF" "franc" = '(1, 1)
+type instance I.Scale "GNF" "centime" = '(100, 1)
+-- | Guatemalan quetzal
+type instance I.Scale "GTQ" "GTQ" = '(100, 1)
+type instance I.Scale "GTQ" "quetzal" = '(1, 1)
+type instance I.Scale "GTQ" "centavo" = '(100, 1)
+-- | Guyanese dollar
+type instance I.Scale "GYD" "GYD" = '(100, 1)
+type instance I.Scale "GYD" "dollar" = '(1, 1)
+type instance I.Scale "GYD" "cent" = '(100, 1)
+-- | Hong Kong dollar
+type instance I.Scale "HKD" "HKD" = '(100, 1)
+type instance I.Scale "HKD" "dollar" = '(1, 1)
+type instance I.Scale "HKD" "cent" = '(100, 1)
+-- | Honduran lempira
+type instance I.Scale "HNL" "HNL" = '(100, 1)
+type instance I.Scale "HNL" "lempira" = '(1, 1)
+type instance I.Scale "HNL" "centavo" = '(100, 1)
+-- | Croatian kuna
+type instance I.Scale "HRK" "HRK" = '(100, 1)
+type instance I.Scale "HRK" "kuna" = '(1, 1)
+type instance I.Scale "HRK" "lipa" = '(100, 1)
+-- | Haitian gourde
+type instance I.Scale "HTG" "HTG" = '(100, 1)
+type instance I.Scale "HTG" "gourde" = '(1, 1)
+type instance I.Scale "HTG" "centime" = '(1, 1)
+-- | Hungarian forint
+type instance I.Scale "HUF" "HUF" = '(100, 1)
+type instance I.Scale "HUF" "forint" = '(1, 1)
+type instance I.Scale "HUF" "filler" = '(100, 1)
+-- | Indonesian rupiah
+type instance I.Scale "IDR" "IDR" = '(100, 1)
+type instance I.Scale "IDR" "rupiah" = '(1, 1)
+type instance I.Scale "IDR" "sen" = '(100, 1)
+-- | Israeli new shekel
+type instance I.Scale "ILS" "ILS" = '(100, 1)
+type instance I.Scale "ILS" "shekel" = '(1, 1)
+type instance I.Scale "ILS" "agora" = '(100, 1)
+-- | Indian rupee
+type instance I.Scale "INR" "INR" = '(100, 1)
+type instance I.Scale "INR" "rupee" = '(1, 1)
+type instance I.Scale "INR" "paisa" = '(100, 1)
+-- | Iraqi dinar
+type instance I.Scale "IQD" "IQD" = '(1000, 1)
+type instance I.Scale "IQD" "dinar" = '(1, 1)
+type instance I.Scale "IQD" "fils" = '(1000, 1)
+-- | Iranian rial
+type instance I.Scale "IRR" "IRR" = '(100, 1)
+type instance I.Scale "IRR" "rial" = '(1, 1)
+type instance I.Scale "IRR" "dinar" = '(100, 1)
+-- | Icelandic króna
+type instance I.Scale "ISK" "ISK" = '(100, 1)
+type instance I.Scale "ISK" "krona" = '(1, 1)
+type instance I.Scale "ISK" "eyrir" = '(100, 1)
+-- | Jamaican dollar
+type instance I.Scale "JMD" "JMD" = '(100, 1)
+type instance I.Scale "JMD" "dollar" = '(1, 1)
+type instance I.Scale "JMD" "cent" = '(100, 1)
+-- | Jordanian dinar
+type instance I.Scale "JOD" "JOD" = '(100, 1)
+type instance I.Scale "JOD" "dinar" = '(1, 1)
+type instance I.Scale "JOD" "piastre" = '(100, 1)
+-- | Japanese yen
+type instance I.Scale "JPY" "JPY" = '(100, 1)
+type instance I.Scale "JPY" "yen" = '(1, 1)
+type instance I.Scale "JPY" "sen" = '(100, 1)
+-- | Kenyan shilling
+type instance I.Scale "KES" "KES" = '(100, 1)
+type instance I.Scale "KES" "shilling" = '(1, 1)
+type instance I.Scale "KES" "cent" = '(100, 1)
+-- | Kyrgyzstani som
+type instance I.Scale "KGS" "KGS" = '(100, 1)
+type instance I.Scale "KGS" "som" = '(1, 1)
+type instance I.Scale "KGS" "tyiyn" = '(100, 1)
+-- | Cambodian riel
+type instance I.Scale "KHR" "KHR" = '(100, 1)
+type instance I.Scale "KHR" "riel" = '(1, 1)
+type instance I.Scale "KHR" "sen" = '(100, 1)
+-- | Comorian franc
+type instance I.Scale "KMF" "KMF" = '(100, 1)
+type instance I.Scale "KMF" "franc" = '(1, 1)
+type instance I.Scale "KMF" "centime" = '(100, 1)
+-- | North Korean won
+type instance I.Scale "KPW" "KPW" = '(100, 1)
+type instance I.Scale "KPW" "won" = '(1, 1)
+type instance I.Scale "KPW" "chon" = '(100, 1)
+-- | South Korean won
+type instance I.Scale "KRW" "KRW" = '(100, 1)
+type instance I.Scale "KRW" "won" = '(1, 1)
+type instance I.Scale "KRW" "jeon" = '(100, 1)
+-- | Kuwaiti dinar
+type instance I.Scale "KWD" "KWD" = '(1000, 1)
+type instance I.Scale "KWD" "dinar" = '(1, 1)
+type instance I.Scale "KWD" "fils" = '(1000, 1)
+-- | Cayman Islands dollar
+type instance I.Scale "KYD" "KYD" = '(100, 1)
+type instance I.Scale "KYD" "dollar" = '(1, 1)
+type instance I.Scale "KYD" "cent" = '(100, 1)
+-- | Kazakhstani tenge
+type instance I.Scale "KZT" "KZT" = '(100, 1)
+type instance I.Scale "KZT" "tenge" = '(1, 1)
+type instance I.Scale "KZT" "tiyin" = '(100, 1)
+-- | Lao kip
+type instance I.Scale "LAK" "LAK" = '(100, 1)
+type instance I.Scale "LAK" "kip" = '(1, 1)
+type instance I.Scale "LAK" "att" = '(100, 1)
+-- | Lebanese pound
+type instance I.Scale "LBP" "LBP" = '(100, 1)
+type instance I.Scale "LBP" "pound" = '(1, 1)
+type instance I.Scale "LBP" "piastre" = '(100, 1)
+-- | Sri Lankan rupee
+type instance I.Scale "LKR" "LKR" = '(100, 1)
+type instance I.Scale "LKR" "rupee" = '(1, 1)
+type instance I.Scale "LKR" "cent" = '(100, 1)
+-- | Liberian dollar
+type instance I.Scale "LRD" "LRD" = '(100, 1)
+type instance I.Scale "LRD" "dollar" = '(1, 1)
+type instance I.Scale "LRD" "cent" = '(100, 1)
+-- | Lesotho loti
+type instance I.Scale "LSL" "LSL" = '(100, 1)
+type instance I.Scale "LSL" "loti" = '(1, 1)
+type instance I.Scale "LSL" "sente" = '(100, 1)
+-- | Libyan dinar
+type instance I.Scale "LYD" "LYD" = '(100, 1)
+type instance I.Scale "LYD" "dinar" = '(1, 1)
+type instance I.Scale "LYD" "dirham" = '(1000, 1)
+-- | Moroccan dirham
+type instance I.Scale "MAD" "MAD" = '(100, 1)
+type instance I.Scale "MAD" "dirham" = '(1, 1)
+type instance I.Scale "MAD" "centime" = '(100, 1)
+-- | Moldovan leu
+type instance I.Scale "MDL" "MDL" = '(100, 1)
+type instance I.Scale "MDL" "leu" = '(100, 1)
+type instance I.Scale "MDL" "ban" = '(100, 1)
+-- | Malagasy ariary
+type instance I.Scale "MGA" "MGA" = '(5, 1)
+type instance I.Scale "MGA" "ariary" = '(1, 1)
+type instance I.Scale "MGA" "iraimbilanja" = '(5, 1)
+-- | Macedonian denar
+type instance I.Scale "MKD" "MKD" = '(100, 1)
+type instance I.Scale "MKD" "denar" = '(1, 1)
+type instance I.Scale "MKD" "deni" = '(100, 1)
+-- | Myanmar kyat
+type instance I.Scale "MMK" "MMK" = '(100, 1)
+type instance I.Scale "MMK" "kyat" = '(1, 1)
+type instance I.Scale "MMK" "pya" = '(100, 1)
+-- | Mongolian tugrik
+type instance I.Scale "MNT" "MNT" = '(100, 1)
+type instance I.Scale "MNT" "tugrik" = '(1, 1)
+type instance I.Scale "MNT" "mongo" = '(100, 1)
+-- | Macanese pataca
+type instance I.Scale "MOP" "MOP" = '(100, 1)
+type instance I.Scale "MOP" "pataca" = '(1, 1)
+type instance I.Scale "MOP" "avo" = '(100, 1)
+-- | Mauritanian ouguiya
+type instance I.Scale "MRO" "MRO" = '(5, 1)
+type instance I.Scale "MRO" "ouguiya" = '(1, 1)
+type instance I.Scale "MRO" "khoums" = '(5, 1)
+-- | Mauritian rupee
+type instance I.Scale "MUR" "MUR" = '(100, 1)
+type instance I.Scale "MUR" "rupee" = '(1, 1)
+type instance I.Scale "MUR" "cent" = '(100, 1)
+-- | Maldivian rufiyaa
+type instance I.Scale "MVR" "MVR" = '(100, 1)
+type instance I.Scale "MVR" "rufiyaa" = '(1, 1)
+type instance I.Scale "MVR" "laari" = '(100, 1)
+-- | Malawian kwacha
+type instance I.Scale "MWK" "MWK" = '(100, 1)
+type instance I.Scale "MWK" "kwacha" = '(1, 1)
+type instance I.Scale "MWK" "tambala" = '(100, 1)
+-- | Mexican peso
+type instance I.Scale "MXN" "MXN" = '(100, 1)
+type instance I.Scale "MXN" "peso" = '(1, 1)
+type instance I.Scale "MXN" "centavo" = '(100, 1)
+-- | Mexican unidad de inversion
+type instance I.Scale "MXV" "MXV" = '(100, 1)
+-- | Malaysian ringgit
+type instance I.Scale "MYR" "MYR" = '(100, 1)
+type instance I.Scale "MYR" "ringgit" = '(1, 1)
+type instance I.Scale "MYR" "sen" = '(100, 1)
+-- | Mozambican metical
+type instance I.Scale "MZN" "MZN" = '(100, 1)
+type instance I.Scale "MZN" "metical" = '(1, 1)
+type instance I.Scale "MZN" "centavo" = '(100, 1)
+-- | Namibian dollar
+type instance I.Scale "NAD" "NAD" = '(100, 1)
+type instance I.Scale "NAD" "dollar" = '(1, 1)
+type instance I.Scale "NAD" "cent" = '(100, 1)
+-- | Nigerian naira
+type instance I.Scale "NGN" "NGN" = '(100, 1)
+type instance I.Scale "NGN" "naira" = '(1, 1)
+type instance I.Scale "NGN" "kobo" = '(100, 1)
+-- | Nicaraguan cordoba
+type instance I.Scale "NIO" "NIO" = '(100, 1)
+type instance I.Scale "NIO" "cordoba" = '(1, 1)
+type instance I.Scale "NIO" "centavo" = '(100, 1)
+-- | Norwegian krone
+type instance I.Scale "NOK" "NOK" = '(100, 1)
+type instance I.Scale "NOK" "krone" = '(1, 1)
+type instance I.Scale "NOK" "ore" = '(100, 1)
+-- | Nepalese rupee
+type instance I.Scale "NPR" "NPR" = '(100, 1)
+type instance I.Scale "NPR" "rupee" = '(1, 1)
+type instance I.Scale "NPR" "paisa" = '(100, 1)
+-- | New Zealand dollar
+type instance I.Scale "NZD" "NZD" = '(100, 1)
+type instance I.Scale "NZD" "dollar" = '(1, 1)
+type instance I.Scale "NZD" "cent" = '(100, 1)
+-- | Omani rial
+type instance I.Scale "OMR" "OMR" = '(1000, 1)
+type instance I.Scale "OMR" "rial" = '(1, 1)
+type instance I.Scale "OMR" "baisa" = '(1000, 1)
+-- | Panamenian balboa
+type instance I.Scale "PAB" "PAB" = '(100, 1)
+type instance I.Scale "PAB" "balboa" = '(1, 1)
+type instance I.Scale "PAB" "centesimo" = '(100, 1)
+-- | Peruvian sol
+type instance I.Scale "PEN" "PEN" = '(100, 1)
+type instance I.Scale "PEN" "sol" = '(1, 1)
+type instance I.Scale "PEN" "centimo" = '(100, 1)
+-- | Papua New Guinean kina
+type instance I.Scale "PGK" "PGK" = '(100, 1)
+type instance I.Scale "PGK" "kina" = '(1, 1)
+type instance I.Scale "PGK" "toea" = '(100, 1)
+-- | Philippine peso
+type instance I.Scale "PHP" "PHP" = '(100, 1)
+type instance I.Scale "PHP" "peso" = '(1, 1)
+type instance I.Scale "PHP" "centavo" = '(100, 1)
+-- | Pakistani rupee
+type instance I.Scale "PKR" "PKR" = '(100, 1)
+type instance I.Scale "PKR" "rupee" = '(1, 1)
+type instance I.Scale "PKR" "paisa" = '(100, 1)
+-- | Polish zloty
+type instance I.Scale "PLN" "PLN" = '(100, 1)
+type instance I.Scale "PLN" "zloty" = '(1, 1)
+type instance I.Scale "PLN" "grosz" = '(100, 1)
+-- | Paraguayan guarani
+type instance I.Scale "PYG" "PYG" = '(100, 1)
+type instance I.Scale "PYG" "guarani" = '(1, 1)
+type instance I.Scale "PYG" "centimo" = '(100, 1)
+-- | Qatari riyal
+type instance I.Scale "QAR" "QAR" = '(100, 1)
+type instance I.Scale "QAR" "riyal" = '(1, 1)
+type instance I.Scale "QAR" "dirham" = '(100, 1)
+-- | Romanian leu
+type instance I.Scale "RON" "RON" = '(100, 1)
+type instance I.Scale "RON" "leu" = '(1, 1)
+type instance I.Scale "RON" "ban" = '(100, 1)
+-- | Serbian dinar
+type instance I.Scale "RSD" "RSD" = '(100, 1)
+type instance I.Scale "RSD" "dinar" = '(1, 1)
+type instance I.Scale "RSD" "para" = '(100, 1)
+-- | Russian ruble
+type instance I.Scale "RUB" "RUB" = '(100, 1)
+type instance I.Scale "RUB" "ruble" = '(1, 1)
+type instance I.Scale "RUB" "kopek" = '(100, 1)
+-- | Rwandan franc
+type instance I.Scale "RWF" "RWF" = '(100, 1)
+type instance I.Scale "RWF" "franc" = '(1, 1)
+type instance I.Scale "RWF" "centime" = '(100, 1)
+-- | Saudi Arabian riyal
+type instance I.Scale "SAR" "SAR" = '(100, 1)
+type instance I.Scale "SAR" "riyal" = '(1, 1)
+type instance I.Scale "SAR" "halala" = '(100, 1)
+-- | Solomon Islands dollar
+type instance I.Scale "SBD" "SBD" = '(100, 1)
+type instance I.Scale "SBD" "dollar" = '(100, 1)
+type instance I.Scale "SBD" "cent" = '(100, 1)
+-- | Seychellois rupee
+type instance I.Scale "SCR" "SCR" = '(100, 1)
+type instance I.Scale "SCR" "rupee" = '(1, 1)
+type instance I.Scale "SCR" "cent" = '(100, 1)
+-- | Sudanese pound
+type instance I.Scale "SDG" "SDG" = '(100, 1)
+type instance I.Scale "SDG" "pound" = '(1, 1)
+type instance I.Scale "SDG" "piastre" = '(100, 1)
+-- | Swedish krona
+type instance I.Scale "SEK" "SEK" = '(100, 1)
+type instance I.Scale "SEK" "krona" = '(1, 1)
+type instance I.Scale "SEK" "ore" = '(100, 1)
+-- | Singapore dollar
+type instance I.Scale "SGD" "SGD" = '(100, 1)
+type instance I.Scale "SGD" "dollar" = '(1, 1)
+type instance I.Scale "SGD" "cent" = '(100, 1)
+-- | Saint Helena pound
+type instance I.Scale "SHP" "SHP" = '(100, 1)
+type instance I.Scale "SHP" "pound" = '(1, 1)
+type instance I.Scale "SHP" "penny" = '(100, 1)
+-- | Sierra Leonean leone
+type instance I.Scale "SLL" "SLL" = '(100, 1)
+type instance I.Scale "SLL" "leone" = '(1, 1)
+type instance I.Scale "SLL" "cent" = '(100, 1)
+-- | Somali shilling
+type instance I.Scale "SOS" "SOS" = '(100, 1)
+type instance I.Scale "SOS" "shilling" = '(1, 1)
+type instance I.Scale "SOS" "cent" = '(100, 1)
+-- | Surinamese dollar
+type instance I.Scale "SRD" "SRD" = '(100, 1)
+type instance I.Scale "SRD" "dollar" = '(1, 1)
+type instance I.Scale "SRD" "cent" = '(100, 1)
+-- | South Sudanese pound
+type instance I.Scale "SSP" "SSP" = '(100, 1)
+type instance I.Scale "SSP" "pound" = '(1, 1)
+type instance I.Scale "SSP" "piastre" = '(100, 1)
+-- | Sao Tome and Principe dobra
+type instance I.Scale "STD" "STD" = '(100, 1)
+type instance I.Scale "STD" "dobra" = '(1, 1)
+type instance I.Scale "STD" "centimo" = '(100, 1)
+-- | Salvadoran colon
+type instance I.Scale "SVC" "SVC" = '(100, 1)
+type instance I.Scale "SVC" "colon" = '(1, 1)
+type instance I.Scale "SVC" "centavo" = '(100, 1)
+-- | Syrian pound
+type instance I.Scale "SYP" "SYP" = '(100, 1)
+type instance I.Scale "SYP" "pound" = '(1, 1)
+type instance I.Scale "SYP" "piastre" = '(100, 1)
+-- | Swazi lilangeni
+type instance I.Scale "SZL" "SZL" = '(100, 1)
+type instance I.Scale "SZL" "lilangeni" = '(1, 1)
+type instance I.Scale "SZL" "cent" = '(100, 1)
+-- | Thai baht
+type instance I.Scale "THB" "THB" = '(100, 1)
+type instance I.Scale "THB" "baht" = '(1, 1)
+type instance I.Scale "THB" "satang" = '(100, 1)
+-- | Tajikistani somoni
+type instance I.Scale "TJS" "TJS" = '(100, 1)
+type instance I.Scale "TJS" "somoni" = '(1, 1)
+type instance I.Scale "TJS" "diram" = '(100, 1)
+-- | Turkmen manat
+type instance I.Scale "TMT" "TMT" = '(100, 1)
+type instance I.Scale "TMT" "manat" = '(1, 1)
+type instance I.Scale "TMT" "tennesi" = '(100, 1)
+-- | Tunisian dinar
+type instance I.Scale "TND" "TND" = '(1000, 1)
+type instance I.Scale "TND" "dinar" = '(1, 1)
+type instance I.Scale "TND" "millime" = '(1000, 1)
+-- | Tongan pa’anga
+type instance I.Scale "TOP" "TOP" = '(100, 1)
+type instance I.Scale "TOP" "pa'anga" = '(1, 1)
+type instance I.Scale "TOP" "seniti" = '(100, 1)
+-- | Turkish lira
+type instance I.Scale "TRY" "TRY" = '(100, 1)
+type instance I.Scale "TRY" "lira" = '(1, 1)
+type instance I.Scale "TRY" "kurus" = '(100, 1)
+-- | Tobago Trinidad and Tobago dollar
+type instance I.Scale "TTD" "TTD" = '(100, 1)
+type instance I.Scale "TTD" "dollar" = '(1, 1)
+type instance I.Scale "TTD" "cent" = '(100, 1)
+-- | New Taiwan dollar
+type instance I.Scale "TWD" "TWD" = '(100, 1)
+type instance I.Scale "TWD" "dollar" = '(1, 1)
+type instance I.Scale "TWD" "cent" = '(100, 1)
+-- | Tanzanian shilling
+type instance I.Scale "TZS" "TZS" = '(100, 1)
+type instance I.Scale "TZS" "shilling" = '(1, 1)
+type instance I.Scale "TZS" "cent" = '(100, 1)
+-- | Ukrainian hryvnia
+type instance I.Scale "UAH" "UAH" = '(100, 1)
+type instance I.Scale "UAH" "hryvnia" = '(1, 1)
+type instance I.Scale "UAH" "kopiyka" = '(100, 1)
+-- | Ugandan shilling
+type instance I.Scale "UGX" "UGX" = '(100, 1)
+type instance I.Scale "UGX" "shilling" = '(1, 1)
+type instance I.Scale "UGX" "cent" = '(100, 1)
+-- | United States dollar
+type instance I.Scale "USD" "USD" = '(100, 1)
+type instance I.Scale "USD" "dollar" = '(1, 1)
+type instance I.Scale "USD" "cent" = '(100, 1)
+-- | United States dollar (next day)
+type instance I.Scale "USN" "USN" = '(100, 1)
+-- | Uruguayan peso en unidades
+type instance I.Scale "UYI" "UYI" = '(100, 1)
+-- | Uruguayan peso
+type instance I.Scale "UYU" "UYU" = '(100, 1)
+type instance I.Scale "UYU" "peso" = '(1, 1)
+type instance I.Scale "UYU" "centesimo" = '(100, 1)
+-- | Uzbekistani som
+type instance I.Scale "UZS" "UZS" = '(100, 1)
+type instance I.Scale "UZS" "som" = '(1, 1)
+type instance I.Scale "UZS" "tiyin" = '(100, 1)
+-- | Venezuelan bolivar
+type instance I.Scale "VEF" "VEF" = '(100, 1)
+type instance I.Scale "VEF" "bolivar" = '(1, 1)
+type instance I.Scale "VEF" "centimo" = '(100, 1)
+-- | Vietnamese dong
+type instance I.Scale "VND" "VND" = '(10, 1)
+type instance I.Scale "VND" "dong" = '(1, 1)
+type instance I.Scale "VND" "hao" = '(10, 1)
+-- | Vanuatu vatu
+type instance I.Scale "VUV" "VUV" = '(1, 1)
+type instance I.Scale "VUV" "vatu" = '(1, 1)
+-- | Samoan tālā
+type instance I.Scale "WST" "WST" = '(100, 1)
+type instance I.Scale "WST" "tala" = '(1, 1)
+type instance I.Scale "WST" "sene" = '(100, 1)
+-- | Central African CFA franc
+type instance I.Scale "XAF" "XAF" = '(100, 1)
+type instance I.Scale "XAF" "franc" = '(1, 1)
+type instance I.Scale "XAF" "centime" = '(100, 1)
+-- | East Caribbean dollar
+type instance I.Scale "XCD" "XCD" = '(100, 1)
+type instance I.Scale "XCD" "dollar" = '(1, 1)
+type instance I.Scale "XCD" "cent" = '(100, 1)
+-- | International Monetary Fund Special Drawing Right
+type instance I.Scale "XDR" "XDR" = '(100, 1)
+-- | West African CFA franc
+type instance I.Scale "XOF" "XOF" = '(100, 1)
+type instance I.Scale "XOF" "franc" = '(1, 1)
+type instance I.Scale "XOF" "centime" = '(100, 1)
+-- | CFP franc
+type instance I.Scale "XPF" "XPF" = '(100, 1)
+type instance I.Scale "XPF" "franc" = '(1, 1)
+type instance I.Scale "XPF" "centime" = '(100, 1)
+-- | Sucre
+type instance I.Scale "XSU" "XSU" = '(100, 1)
+-- | African Development Bank unit of account
+type instance I.Scale "XUA" "XUA" = '(100, 1)
+-- | Yemeni rial
+type instance I.Scale "YER" "YER" = '(100, 1)
+type instance I.Scale "YER" "rial" = '(1, 1)
+type instance I.Scale "YER" "fils" = '(100, 1)
+-- | South African rand
+type instance I.Scale "ZAR" "ZAR" = '(100, 1)
+type instance I.Scale "ZAR" "rand" = '(1, 1)
+type instance I.Scale "ZAR" "cent" = '(100, 1)
+-- | Zambian kwacha
+type instance I.Scale "ZMW" "ZMW" = '(100, 1)
+type instance I.Scale "ZMW" "kwacha" = '(1, 1)
+type instance I.Scale "ZMW" "ngwee" = '(100, 1)
+-- | Zimbawe dollar
+type instance I.Scale "ZWL" "ZWL" = '(100, 1)
+type instance I.Scale "ZWL" "dollar" = '(1, 1)
+type instance I.Scale "ZWL" "cent" = '(100, 1)
+
+-- | Gold. No canonical smallest unit. Unusable instance.
+type instance I.Scale "XAU" "XAU" = I.ErrScaleNonCanonical "XAU"
+type instance I.Scale "XAU" "troy-ounce" = '(1, 1)
+type instance I.Scale "XAU" "grain" = '(480, 1)
+type instance I.Scale "XAU" "milligrain" = '(480000, 1)
+type instance I.Scale "XAU" "micrograin" = '(480000000, 1)
+type instance I.Scale "XAU" "kilogram" = '(31103477, 1000000000)
+type instance I.Scale "XAU" "gram" = '(31103477, 1000000)
+type instance I.Scale "XAU" "milligram" = '(31103477, 1000)
+type instance I.Scale "XAU" "microgram" = '(31103477, 1)
+
+-- | Silver. No canonical smallest unit. Unusable instance.
+type instance I.Scale "XAG" "XAG" = I.ErrScaleNonCanonical "XAG"
+type instance I.Scale "XAG" "troy-ounce" = '(1, 1)
+type instance I.Scale "XAG" "grain" = '(480, 1)
+type instance I.Scale "XAG" "milligrain" = '(480000, 1)
+type instance I.Scale "XAG" "micrograin" = '(480000000, 1)
+type instance I.Scale "XAG" "kilogram" = '(31103477, 1000000000)
+type instance I.Scale "XAG" "gram" = '(31103477, 1000000)
+type instance I.Scale "XAG" "milligram" = '(31103477, 1000)
+type instance I.Scale "XAG" "microgram" = '(31103477, 1)
+
+-- | Palladium. No canonical smallest unit. Unusable instance.
+type instance I.Scale "XPD" "XPD" = I.ErrScaleNonCanonical "XPD"
+type instance I.Scale "XPD" "troy-ounce" = '(1, 1)
+type instance I.Scale "XPD" "grain" = '(480, 1)
+type instance I.Scale "XPD" "milligrain" = '(480000, 1)
+type instance I.Scale "XPD" "micrograin" = '(480000000, 1)
+type instance I.Scale "XPD" "kilogram" = '(31103477, 1000000000)
+type instance I.Scale "XPD" "gram" = '(31103477, 1000000)
+type instance I.Scale "XPD" "milligram" = '(31103477, 1000)
+type instance I.Scale "XPD" "microgram" = '(31103477, 1)
+
+-- | Platinum. No canonical smallest unit. Unusable instance.
+type instance I.Scale "XPT" "XPT" = I.ErrScaleNonCanonical "XPT"
+type instance I.Scale "XPT" "troy-ounce" = '(1, 1)
+type instance I.Scale "XPT" "grain" = '(480, 1)
+type instance I.Scale "XPT" "milligrain" = '(480000, 1)
+type instance I.Scale "XPT" "micrograin" = '(480000000, 1)
+type instance I.Scale "XPT" "kilogram" = '(31103477, 1000000000)
+type instance I.Scale "XPT" "gram" = '(31103477, 1000000)
+type instance I.Scale "XPT" "milligram" = '(31103477, 1000)
+type instance I.Scale "XPT" "microgram" = '(31103477, 1)
+
+-- | Bitcoin
+type instance I.Scale "BTC" "BTC" = '(100000000, 1)
+type instance I.Scale "BTC" "bitcoin" = '(1, 1)
+type instance I.Scale "BTC" "satoshi" = '(100000000, 1)
+
+-- | Bitcoin
+type instance I.Scale "XBT" "XBT" = '(100000000, 1)
+type instance I.Scale "XBT" "bitcoin" = '(1, 1)
+type instance I.Scale "XBT" "satoshi" = '(100000000, 1)
+
+-- | Ether
+type instance I.Scale "ETH" "ETH" = '(1000000000000000000, 1)
+type instance I.Scale "ETH" "ether" = '(1, 1)
+type instance I.Scale "ETH" "kwei" = '(1000, 1)
+type instance I.Scale "ETH" "babbage" = '(1000, 1)
+type instance I.Scale "ETH" "mwei" = '(1000000, 1)
+type instance I.Scale "ETH" "lovelace" = '(1000000, 1)
+type instance I.Scale "ETH" "gwei" = '(1000000000, 1)
+type instance I.Scale "ETH" "shannon" = '(1000000000, 1)
+type instance I.Scale "ETH" "microether" = '(1000000000000, 1)
+type instance I.Scale "ETH" "szabo" = '(1000000000000, 1)
+type instance I.Scale "ETH" "finney" = '(1000000000000000, 1)
+type instance I.Scale "ETH" "milliether" = '(1000000000000000, 1)
+type instance I.Scale "ETH" "wei" = '(1000000000000000000, 1)
diff --git a/src/Money/Internal.hs b/src/Money/Internal.hs
new file mode 100644
--- /dev/null
+++ b/src/Money/Internal.hs
@@ -0,0 +1,1188 @@
+{-# LANGUAGE BangPatterns #-}
+{-# LANGUAGE CPP #-}
+{-# LANGUAGE ConstraintKinds #-}
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE DeriveGeneric #-}
+{-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE GeneralizedNewtypeDeriving #-}
+{-# LANGUAGE KindSignatures #-}
+{-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE PolyKinds #-}
+{-# LANGUAGE RankNTypes #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE StandaloneDeriving #-}
+{-# LANGUAGE TypeFamilies #-}
+{-# LANGUAGE TypeOperators #-}
+{-# LANGUAGE UndecidableInstances #-}
+
+#if MIN_VERSION_base(4,9,0)
+{-# OPTIONS_GHC -Wno-redundant-constraints #-}
+#endif
+
+-- | This is an internal module. Import "Money" instead.
+module Money.Internal
+ ( -- * Dense monetary values
+   Dense
+ , dense
+   -- * Discrete monetary values
+ , Discrete
+ , Discrete'
+ , fromDiscrete
+ , round
+ , ceiling
+ , floor
+ , truncate
+   -- * Currency scales
+ , Scale
+ , GoodScale
+ , ErrScaleNonCanonical
+ , scale
+   -- * Currency exchange
+ , ExchangeRate
+ , exchangeRate
+ , fromExchangeRate
+ , flipExchangeRate
+ , exchange
+   -- * Serializable representations
+ , DenseRep
+ , toDenseRep
+ , mkDenseRep
+ , fromDenseRep
+ , withDenseRep
+ , denseRepCurrency
+ , denseRepAmount
+ , denseRepAmountNumerator
+ , denseRepAmountDenominator
+ , DiscreteRep
+ , toDiscreteRep
+ , mkDiscreteRep
+ , fromDiscreteRep
+ , withDiscreteRep
+ , discreteRepCurrency
+ , discreteRepScale
+ , discreteRepScaleNumerator
+ , discreteRepScaleDenominator
+ , discreteRepAmount
+ , ExchangeRateRep
+ , toExchangeRateRep
+ , mkExchangeRateRep
+ , fromExchangeRateRep
+ , withExchangeRateRep
+ , exchangeRateRepSrcCurrency
+ , exchangeRateRepDstCurrency
+ , exchangeRateRepRate
+ , exchangeRateRepRateNumerator
+ , exchangeRateRepRateDenominator
+ ) where
+
+import Control.Applicative (empty)
+import Control.Monad ((<=<))
+import Data.Constraint (Dict(Dict))
+import Data.Proxy (Proxy(..))
+import Data.Ratio ((%), numerator, denominator)
+import qualified GHC.Generics as GHC
+import GHC.Real (infinity, notANumber)
+import GHC.TypeLits
+  (Symbol, SomeSymbol(..), Nat, SomeNat(..), CmpNat, KnownSymbol, KnownNat,
+   natVal, someNatVal, symbolVal, someSymbolVal)
+import Prelude hiding (round, ceiling, floor, truncate)
+import qualified Prelude
+import qualified Text.ParserCombinators.ReadPrec as ReadPrec
+import qualified Text.ParserCombinators.ReadP as ReadP
+import Text.Read (readPrec)
+import Unsafe.Coerce (unsafeCoerce)
+
+#ifdef VERSION_aeson
+import qualified Data.Aeson as Ae
+#endif
+
+#ifdef VERSION_binary
+import qualified Data.Binary as Binary
+#endif
+
+#ifdef VERSION_cereal
+import qualified Data.Serialize as Cereal
+#endif
+
+#ifdef VERSION_deepseq
+import Control.DeepSeq (NFData)
+#endif
+
+#ifdef VERSION_hashable
+import Data.Hashable (Hashable)
+#endif
+
+#ifdef VERSION_store
+import qualified Data.Store as Store
+#endif
+
+#if MIN_VERSION_base(4,9,0)
+import qualified GHC.TypeLits as GHC
+#endif
+
+--------------------------------------------------------------------------------
+-- | 'Dense' represents a dense monetary value for @currency@ (usually a
+-- ISO-4217 currency code, but not necessarily) as a rational number.
+--
+-- While monetary values associated with a particular currency are discrete, you
+-- can still treat monetary values as dense while operating on them. For
+-- example, the half of @USD 3.41@ is @USD 1.705@, which is not an amount that
+-- can't be represented as a number of USD cents (the smallest unit that can
+-- represent USD amounts). Nevertheless, if you eventually multiply @USD 1.705@
+-- by @4@, for example, you end up with @USD 6.82@, which is again a value
+-- representable as USD cents. In other words, 'Dense' monetary values
+-- allow us to perform precise calculations deferring the conversion to a
+-- 'Discrete' monetary values as much as posible. Once you are ready to
+-- aproximate a 'Dense' value to a 'Discrete' value you can use one of
+-- 'round', 'floor', 'ceiling' or 'truncate'. Otherwise, using 'toRational' you
+-- can obtain a precise 'Rational' representation.
+--
+-- Construct 'Dense' monetary values using 'dense', or
+-- 'fromInteger' / 'fromIntegral' if that suffices.
+--
+-- /WARNING/ if you want to treat a dense monetary value as a /Real/ number (for
+-- example, to take the square root of that monetary value), then you are on
+-- your own. We can only guarantee lossless manipulation of rational values, so
+-- you will need to convert back and forth betwen the 'Rational' representation
+-- for 'Dense' and your (likely lossy) representation for /Real/ numbers.
+newtype Dense (currency :: Symbol) = Dense Rational
+  deriving (Eq, Ord, Num, Real, Fractional, GHC.Generic)
+
+instance forall currency. KnownSymbol currency => Show (Dense currency) where
+  show = \(Dense r0) ->
+    let c = symbolVal (Proxy :: Proxy currency)
+    in concat [ "Dense ", show c, " (", show r0, ")" ]
+
+instance forall currency. KnownSymbol currency => Read (Dense currency) where
+  readPrec = do
+    let c = symbolVal (Proxy :: Proxy currency)
+    _ <- ReadPrec.lift (ReadP.string ("Dense " ++ show c ++ " "))
+    maybe empty pure =<< fmap dense readPrec
+
+-- | Build a 'Dense' monetary value from a 'Rational' value.
+--
+-- For example, if you want to represent @USD 12.52316@, then you can use:
+--
+-- @
+-- 'dense' (125316 % 10000)
+-- @
+--
+-- This function returns 'Nothing' in case the given 'Rational' is 'infinity' or
+-- 'notANumber'.
+dense :: Rational -> Maybe (Dense currency)
+dense = \r0 ->
+  if (infinity == r0 || notANumber == r0)
+  then Nothing else Just (Dense r0)
+{-# INLINABLE dense #-}
+
+-- | 'Discrete' represents a discrete monetary value for a @currency@ expresed
+-- as an integer amount of a particular @unit@. For example, with @currency ~
+-- \"USD\"@ and @unit ~ \"cent\"@ you can represent United States Dollars to
+-- their full extent.
+--
+-- @currency@ is usually a ISO-4217 currency code, but not necessarily.
+--
+-- Construct 'Discrete' values using 'fromInteger'.
+--
+-- For example, if you want to represent @GBP 21.05@, where the smallest
+-- represetable unit for a GBP (United Kingdom Pound) is the /penny/, and 100
+-- /pennies/ equal 1 GBP (i.e., @'Scale' \"GBP\" ~ '(100, 1)@), then you can
+-- use:
+--
+-- @
+-- 'fromInteger' 2105 :: Discrete \"GBP\" \"penny\"
+-- @
+--
+-- Because @2015 / 100 == 20.15@.
+type Discrete (currency :: Symbol) (unit :: Symbol)
+  = Discrete' currency (Scale currency unit)
+
+-- | 'Discrete'' represents a discrete monetary value for a @currency@ expresed
+-- as an amount of @scale@, which is a rational number expressed as @(numerator,
+-- denominator)@.
+--
+-- You'll be using 'Discrete' instead of 'Discrete'' most of the time, which
+-- mentions the unit name (such as /cent/ or /centavo/) instead of explicitely
+-- mentioning the unit scale.
+newtype Discrete' (currency :: Symbol) (scale :: (Nat, Nat))
+  = Discrete Integer
+
+deriving instance GoodScale scale => Eq (Discrete' currency scale)
+deriving instance GoodScale scale => Ord (Discrete' currency scale)
+deriving instance GoodScale scale => Enum (Discrete' currency scale)
+deriving instance GoodScale scale => Num (Discrete' currency scale)
+deriving instance GoodScale scale => Real (Discrete' currency scale)
+deriving instance GoodScale scale => Integral (Discrete' currency scale)
+deriving instance GoodScale scale => GHC.Generic (Discrete' currency scale)
+
+instance forall currency scale.
+  ( KnownSymbol currency, GoodScale scale
+  ) => Show (Discrete' currency scale) where
+  show = \d0@(Discrete i0) ->
+    let c = symbolVal (Proxy :: Proxy currency)
+    in concat [ "Discrete ", show c, " (", show (scale d0), ") ", show i0 ]
+
+instance forall currency scale.
+  ( KnownSymbol currency, GoodScale scale
+  ) => Read (Discrete' currency scale) where
+  readPrec = do
+    let c = symbolVal (Proxy :: Proxy currency)
+        s = scale (Proxy :: Proxy scale)
+    _ <- ReadPrec.lift (ReadP.string
+           ("Discrete " ++ show c ++ " (" ++ show s ++ ") ") )
+    Discrete <$> readPrec
+
+#if MIN_VERSION_base(4,9,0)
+instance
+  ( GHC.TypeError
+      (('GHC.Text "The ") 'GHC.:<>:
+       ('GHC.ShowType Discrete') 'GHC.:<>:
+       ('GHC.Text " type is deliberately not a ") 'GHC.:<>:
+       ('GHC.ShowType Fractional) 'GHC.:$$:
+       ('GHC.Text "instance. Convert the ") 'GHC.:<>:
+       ('GHC.ShowType Discrete') 'GHC.:<>:
+       ('GHC.Text " value to a ") 'GHC.:<>:
+       ('GHC.ShowType Dense) 'GHC.:$$:
+       ('GHC.Text "value and use the ") 'GHC.:<>:
+       ('GHC.ShowType Fractional) 'GHC.:<>:
+       ('GHC.Text " features on it instead."))
+  , GoodScale scale
+  ) => Fractional (Discrete' currency scale) where
+  fromRational = undefined
+  recip = undefined
+#endif
+
+-- | Convert currency 'Discrete' monetary value into a 'Dense' monetary
+-- value.
+fromDiscrete
+  :: GoodScale scale
+  => Discrete' currency scale
+  -> Dense currency -- ^
+fromDiscrete = \c@(Discrete i) -> Dense (fromInteger i / scale c)
+{-# INLINABLE fromDiscrete #-}
+
+-- | Internal. Used to implement 'round', 'ceiling', 'floor' and 'truncate'.
+roundf
+  :: forall currency scale
+  .  GoodScale scale
+  => (Rational -> Integer) -- ^ 'Prelude.round', 'Prelude.ceiling' or similar.
+  -> Dense currency
+  -> (Discrete' currency scale, Maybe (Dense currency))
+roundf f = \c0 ->
+  let !r0 = toRational c0 :: Rational
+      !r1 = scale (Proxy :: Proxy scale)
+      !i2 = f (r0 * r1) :: Integer
+      !r2 = fromInteger i2 / r1 :: Rational
+      !ycrest | r0 == r2  = Nothing
+              | otherwise = Just (Dense (r0 - r2))
+      !d2 = Discrete i2
+  in (d2, ycrest)
+{-# INLINABLE roundf #-}
+
+-- | Round a 'Dense' value @x@ to the nearest value fully representable in
+-- its @currency@'s @unit@ 'Scale', which might be @x@ itself.
+--
+-- If @x@ is already fully representable in its @currency@'s @unit@ 'Scale',
+-- then the following holds:
+--
+-- @
+-- 'round' x == (x, 'Nothing')
+-- @
+--
+-- Otherwise, if the nearest value to @x@ that is fully representable in its
+-- @currency@'s @unit@ 'Scale' is greater than @x@, then the following holds:
+--
+-- @
+-- 'round' == 'ceiling'
+-- @
+--
+-- Otherwise, the nearest value to @x@ that is fully representable in its
+-- @currency@'s @unit@ 'Scale' is smaller than @x@, and the following holds:
+--
+-- @
+-- 'round' == 'floor'
+-- @
+--
+-- Proof that 'round' doesn't lose money:
+--
+-- @
+-- x == case 'round' x of
+--        (y, 'Nothing') -> y
+--        (y, 'Just' z)  -> y + z
+-- @
+round
+  :: GoodScale scale
+  => Dense currency
+  -> (Discrete' currency scale, Maybe (Dense currency)) -- ^
+round = roundf Prelude.round
+{-# INLINABLE round #-}
+
+-- | Round a 'Dense' value @x@ to the nearest value fully representable in
+-- its @currency@'s @unit@ 'Scale' which is greater than @x@ or equal to @x@.
+--
+--
+-- If @x@ is already fully representable in its @currency@'s @unit@ 'Scale',
+-- then the following holds:
+--
+-- @
+-- 'ceiling' x == (x, 'Nothing')
+-- @
+--
+-- Otherwise, if @x@ is not representable in its @currency@'s @unit@ 'Scale',
+-- then the following holds:
+--
+-- @
+-- 'ceiling' x == (y, 'Just' z)
+-- @
+--
+-- @
+-- x /= y
+-- @
+--
+-- @
+-- z < 'zero'
+-- @
+--
+-- Proof that 'ceiling' doesn't lose money:
+--
+-- @
+-- x == case 'ceiling' x of
+--        (y, 'Nothing') -> y
+--        (y, 'Just' z)  -> y + z
+-- @
+ceiling
+  :: GoodScale scale
+  => Dense currency
+  -> (Discrete' currency scale, Maybe (Dense currency)) -- ^
+ceiling = roundf Prelude.ceiling
+{-# INLINABLE ceiling #-}
+
+-- | Round a 'Dense' value @x@ to the nearest value fully representable in
+-- its @currency@'s @unit@ 'Scale' which is smaller than @x@ or equal to @x@.
+--
+--
+-- If @x@ is already fully representable in its @currency@'s @unit@ 'Scale',
+-- then the following holds:
+--
+-- @
+-- 'floor' x == (x, 'Nothing')
+-- @
+--
+-- Otherwise, if @x@ is not representable in its @currency@'s @unit@ 'Scale',
+-- then the following holds:
+--
+-- @
+-- 'floor' x == (y, 'Just' z)
+-- @
+--
+-- @
+-- x /= y
+-- @
+--
+-- @
+-- z > 'zero'
+-- @
+--
+-- Proof that 'floor' doesn't lose money:
+--
+-- @
+-- x == case 'floor' x of
+--        (y, 'Nothing') -> y
+--        (y, 'Just' z)  -> y + z
+-- @
+floor
+  :: GoodScale scale
+  => Dense currency
+  -> (Discrete' currency scale, Maybe (Dense currency)) -- ^
+floor = roundf Prelude.floor
+{-# INLINABLE floor #-}
+
+-- | Round a 'Dense' value @x@ to the nearest value between zero and
+-- @x@ (inclusive) which is fully representable in its @currency@'s @unit@
+-- 'Scale'.
+--
+-- If @x@ is already fully representable in its @currency@'s @unit@ 'Scale',
+-- then the following holds:
+--
+-- @
+-- 'truncate' x == (x, 'Nothing')
+-- @
+--
+-- Otherwise, if @x@ is positive, then the following holds:
+--
+-- @
+-- 'truncate' == 'floor'
+-- @
+--
+-- Otherwise, if @x@ is negative, the following holds:
+--
+-- @
+-- 'truncate' == 'ceiling'
+-- @
+--
+-- Proof that 'truncate' doesn't lose money:
+--
+-- @
+-- x == case 'truncate' x of
+--        (y, 'Nothing') -> y
+--        (y, 'Just' z)  -> y + z
+-- @
+truncate
+  :: GoodScale scale
+  => Dense currency
+  -> (Discrete' currency scale, Maybe (Dense currency)) -- ^
+truncate = roundf Prelude.truncate
+{-# INLINABLE truncate #-}
+
+--------------------------------------------------------------------------------
+
+-- | @'Scale' currency unit@ is a rational number (expressed as @'(numerator,
+-- denominator)@) indicating how many pieces of @unit@ fit in @currency@.
+--
+-- @currency@ is usually a ISO-4217 currency code, but not necessarily.
+--
+-- The 'Scale' will determine how to convert a 'Dense' value into a
+-- 'Discrete' value and vice-versa.
+--
+-- For example, there are 100 USD cents in 1 USD, so the scale for this
+-- relationship is:
+--
+-- @
+-- type instance 'Scale' \"USD\" \"cent\" = '(100, 1)
+-- @
+--
+-- As another example, there is 1 dollar in USD, so the scale for this
+-- relationship is:
+--
+-- @
+-- type instance 'Scale' \"USD\" \"dollar\" = '(1, 1)
+-- @
+--
+-- When using 'Discrete' values to represent money, it will be impossible to
+-- represent an amount of @currency@ smaller than @unit@. So, if you decide to
+-- use @Scale \"USD\" \"dollar\"@ as your scale, you will not be able to
+-- represent values such as USD 3.50 or USD 21.87, since they are not exact
+-- multiples of a dollar.
+--
+-- If there exists a canonical smallest @unit@ that can fully represent the
+-- currency, then an instance @'Scale' currency currency@ exists.
+--
+-- @
+-- type instance 'Scale' \"USD\" \"USD\" = Scale \"USD\" \"cent\"
+-- @
+--
+-- For some monetary values, such as precious metals, the smallest representable
+-- unit is not obvious, since you can continue to split the precious metal many
+-- times before it stops being a precious metal. Still, for practical purposes
+-- we can make a sane arbitrary choice of smallest unit. For example, the base
+-- unit for XAU (Gold) is the /troy ounce/, which is too big to be considered
+-- the smallest unit, but we can arbitrarily choose the /milligrain/ as our
+-- smallest unit, which is about as heavy as a single grain of table salt and
+-- should be sufficiently precise for all monetary practical purposes. A /troy
+-- ounce/ equals 480000 /milligrains/.
+--
+-- @
+-- type instance 'Scale' \"XAG\" \"milligrain\" = '(480000, 1)
+-- @
+--
+-- You can use other units such as /milligrams/ for measuring XAU, for example.
+-- However, since the amount of /milligrams/ in a /troy ounce/ (31103.477) is
+-- not integral, we need to use rational number to express it.
+--
+-- @
+-- type instance 'Scale' \"XAU\" \"milligram\" = '(31103477, 1000)
+-- @
+--
+-- If you try to obtain the 'Scale of a @currency@ without an obvious smallest
+-- representable @unit@, like XAU, you will get a compile error.
+type family Scale (currency :: Symbol) (unit :: Symbol) :: (Nat, Nat)
+
+#if MIN_VERSION_base(4,9,0)
+-- | A friendly 'GHC.TypeError' to use for a @currency@ that doesn't have a
+-- canonical small unit.
+type family ErrScaleNonCanonical (currency :: Symbol) :: k where
+  ErrScaleNonCanonical c = GHC.TypeError
+    ( 'GHC.Text c 'GHC.:<>:
+      'GHC.Text " is not a currency with a canonical smallest unit," 'GHC.:$$:
+      'GHC.Text "be explicit about the currency unit you want to use." )
+#else
+-- | Forbid a @currency@ that doesn't have a canonical small unit.
+--
+-- In GHC versions before 8.0 we can't provide a nice error message here, so we
+-- simply set this to a value that will fail to satisfy 'GoodScale'. As a
+-- consequence, trying to use this 'Scale' will result in a cryptic error saying
+-- /«@Couldn't match type ‘'EQ’ with ‘'LT’@»/.
+type ErrScaleNonCanonical (currency :: Symbol) = '(0, 0)
+#endif
+
+-- | Constraints to a scale (like the one returned by @'Scale' currency unit@)
+-- expected to always be satisfied. In particular, the scale is always
+-- guaranteed to be a positive rational number ('infinity' and 'notANumber' are
+-- forbidden by 'GoodScale').
+type GoodScale (scale :: (Nat, Nat))
+   = ( CmpNat 0 (Fst scale) ~ 'LT
+     , CmpNat 0 (Snd scale) ~ 'LT
+     , KnownNat (Fst scale)
+     , KnownNat (Snd scale)
+     )
+
+-- | If the specified @num@ and @den@ satisfy the expectations of 'GoodScale' at
+-- the type level, then construct a proof for 'GoodScale'.
+mkGoodScale
+  :: forall num den
+  .  (KnownNat num, KnownNat den)
+  => Maybe (Dict (GoodScale '(num, den)))
+mkGoodScale =
+  let n = natVal (Proxy :: Proxy num)
+      d = natVal (Proxy :: Proxy den)
+  in if (n > 0) && (d > 0)
+     then Just (unsafeCoerce (Dict :: Dict ('LT ~ 'LT, 'LT ~ 'LT,
+                                            KnownNat num, KnownNat den)))
+     else Nothing
+{-# INLINABLE mkGoodScale #-}
+
+-- | Term-level representation for the @currency@'s @unit@ 'Scale'.
+--
+-- For example, the 'Scale' for @\"USD\"@ in @\"cent\"@s is @100/1@.
+--
+-- The returned 'Rational' is statically guaranteed to be a positive number, and
+-- to be different from both 'notANumber' and 'infinity'.
+scale :: forall proxy scale. GoodScale scale => proxy scale -> Rational -- ^
+scale = \_ ->
+   natVal (Proxy :: Proxy (Fst scale)) %
+   natVal (Proxy :: Proxy (Snd scale))
+{-# INLINABLE scale #-}
+
+--------------------------------------------------------------------------------
+
+-- | Exchange rate for converting monetary values of currency @src@ into
+-- monetary values of currency @dst@ by multiplying for it.
+--
+-- For example, if in order to convert USD to GBP we have to multiply by 1.2345,
+-- then we can represent this situaion using:
+--
+-- @
+-- 'exchangeRate' (12345 % 10000) :: 'Maybe' ('ExchangeRate' \"USD\" \"GBP\")
+-- @
+newtype ExchangeRate (src :: Symbol) (dst :: Symbol) = ExchangeRate Rational
+  deriving (Eq, Ord, GHC.Generic)
+
+instance forall src dst.
+  ( KnownSymbol src, KnownSymbol dst
+  ) => Show (ExchangeRate src dst) where
+  show = \(ExchangeRate r0) ->
+    let s = symbolVal (Proxy :: Proxy src)
+        d = symbolVal (Proxy :: Proxy dst)
+    in concat [ "ExchangeRate ", show s, " ", show d, " (", show r0, ")" ]
+
+instance forall src dst.
+  ( KnownSymbol src, KnownSymbol dst
+  ) => Read (ExchangeRate (src :: Symbol) (dst :: Symbol)) where
+  readPrec = do
+    let s = symbolVal (Proxy :: Proxy src)
+        d = symbolVal (Proxy :: Proxy dst)
+    _ <- ReadPrec.lift (ReadP.string
+            ("ExchangeRate " ++ show s ++ " " ++ show d ++ " "))
+    maybe empty pure =<< fmap exchangeRate readPrec
+
+-- | Obtain a 'Rational' representation of the 'ExchangeRate'.
+--
+-- This 'Rational' is statically guaranteed to be greater than 0, different
+-- from 'infinity' and different from 'notANumber'.
+fromExchangeRate :: ExchangeRate src dst -> Rational
+fromExchangeRate = \(ExchangeRate r0) -> r0
+{-# INLINABLE fromExchangeRate #-}
+
+-- | Safely construct an 'ExchangeRate' from a 'Rational' number.
+--
+-- For construction to succeed, this 'Rational' must be greater than 0,
+-- different from 'infinity' and different from 'notANumber'.
+exchangeRate :: Rational -> Maybe (ExchangeRate src dst)
+exchangeRate = \r0 ->
+  if (r0 <= 0 || infinity == r0 || notANumber == r0)
+  then Nothing else Just (ExchangeRate r0)
+{-# INLINABLE exchangeRate #-}
+
+-- | Flip the direction of an 'ExchangeRate'.
+--
+-- Identity law:
+--
+-- @
+-- 'flipExchangeRate' . 'flipExchangeRate'   ==  'id'
+-- @
+flipExchangeRate :: ExchangeRate a b -> ExchangeRate b a
+flipExchangeRate = \(ExchangeRate x) -> ExchangeRate (1 / x)
+{-# INLINABLE flipExchangeRate #-}
+
+-- | Apply the 'ExchangeRate' to the given @'Dense' src@ monetary value.
+--
+-- Identity law:
+--
+-- @
+-- 'exchange' ('flipExchangeRate' x) . 'exchange' x  ==  'id'
+-- @
+--
+-- Use the /Identity law/ for reasoning about going back and forth between @src@
+-- and @dst@ in order to manage any leftovers that might not be representable as
+-- a 'Discrete' monetary value of @src@.
+exchange :: ExchangeRate src dst -> Dense src -> Dense dst
+exchange = \(ExchangeRate r) -> \(Dense s) -> Dense (r * s)
+{-# INLINABLE exchange #-}
+
+--------------------------------------------------------------------------------
+-- DenseRep
+
+-- | A monomorphic representation of 'Dense' that is easier to serialize and
+-- deserialize than 'Dense' in case you don't know the type indexes involved.
+--
+-- If you are trying to construct a value of this type from some raw input, then
+-- you will need to use the 'mkDenseRep' function.
+--
+-- In order to be able to effectively serialize a 'DenseRep' value, you
+-- need to serialize the following three values (which are the eventual
+-- arguments to 'mkDenseRep'):
+--
+-- * 'denseRepCurrency'
+-- * 'denseRepAmountNumerator'
+-- * 'denseRepAmountDenominator'
+data DenseRep = DenseRep
+  { _denseRepCurrency          :: !String
+  , _denseRepAmountNumerator   :: !Integer
+  , _denseRepAmountDenominator :: !Integer  -- ^ Positive, non-zero.
+  } deriving (Eq, Show, GHC.Generic)
+
+-- | WARNING: This instance does not compare monetary amounts, it just helps you
+-- sort 'DenseRep' values in case you need to put them in a 'Data.Set.Set' or
+-- similar.
+deriving instance Ord DenseRep
+
+-- | Currency name.
+denseRepCurrency :: DenseRep -> String
+denseRepCurrency = _denseRepCurrency
+{-# INLINABLE denseRepCurrency #-}
+
+-- | Currency unit amount.
+denseRepAmount :: DenseRep -> Rational
+denseRepAmount = \dr ->
+  denseRepAmountNumerator dr % denseRepAmountDenominator dr
+{-# INLINABLE denseRepAmount #-}
+
+-- | Currency unit amount numerator.
+denseRepAmountNumerator :: DenseRep -> Integer
+denseRepAmountNumerator = _denseRepAmountNumerator
+{-# INLINABLE denseRepAmountNumerator #-}
+
+-- | Currency unit amount denominator. Positive, non-zero.
+denseRepAmountDenominator :: DenseRep -> Integer
+denseRepAmountDenominator = _denseRepAmountDenominator
+{-# INLINABLE denseRepAmountDenominator #-}
+
+-- | Build a 'DenseRep' from raw values.
+--
+-- This function is intended for deserialization purposes. You need to convert
+-- this 'DenseRep' value to a 'Dense' value in order to do any arithmetic
+-- operation on the monetary value.
+mkDenseRep
+  :: String -- ^ Currency. ('denseRepCurrency')
+  -> Integer -- ^ Scale numerator. ('denseRepAmountNumerator')
+  -> Integer -- ^ Scale denominator (positive, non zero). ('denseRepAmountDenominator')
+  -> Maybe DenseRep
+mkDenseRep = \c n d -> case d > 0 of
+  False -> Nothing
+  True -> Just (DenseRep c n d)
+{-# INLINABLE mkDenseRep #-}
+
+-- | Convert a 'Dense' to a 'DenseRep' for ease of serialization.
+toDenseRep :: KnownSymbol currency => Dense currency -> DenseRep
+toDenseRep = \(Dense r0 :: Dense currency) ->
+  let c = symbolVal (Proxy :: Proxy currency)
+  in DenseRep c (numerator r0) (denominator r0)
+{-# INLINABLE toDenseRep #-}
+
+-- | Attempt to convert a 'DenseRep' to a 'Dense', provided you know the target
+-- @currency@.
+fromDenseRep
+  :: forall currency
+  .  KnownSymbol currency
+  => DenseRep
+  -> Maybe (Dense currency)  -- ^
+fromDenseRep = \dr ->
+  case denseRepCurrency dr == symbolVal (Proxy :: Proxy currency) of
+     False -> Nothing
+     True -> Just (Dense (denseRepAmount dr))
+{-# INLINABLE fromDenseRep #-}
+
+-- | Convert a 'DenseRep' to a 'Dense' without knowing the target @currency@.
+--
+-- Notice that @currency@ here can't leave its intended scope unless you can
+-- prove equality with some other type at the outer scope, but in that case you
+-- would be better off using 'fromDenseRep' directly.
+withDenseRep
+  :: DenseRep
+  -> (forall currency. KnownSymbol currency => Dense currency -> r)
+  -> r  -- ^
+withDenseRep dr = \f ->
+   case someSymbolVal (denseRepCurrency dr) of
+      SomeSymbol (Proxy :: Proxy currency) ->
+         f (Dense (denseRepAmount dr) :: Dense currency)
+{-# INLINABLE withDenseRep #-}
+
+--------------------------------------------------------------------------------
+-- DiscreteRep
+
+-- | A monomorphic representation of 'Discrete' that is easier to serialize and
+-- deserialize than 'Discrete' in case you don't know the type indexes involved.
+--
+-- If you are trying to construct a value of this type from some raw input, then
+-- you will need to use the 'mkDiscreteRep' function.
+--
+-- In order to be able to effectively serialize a 'DiscreteRep' value, you need
+-- to serialize the following four values (which are the eventual arguments to
+-- 'mkDiscreteRep'):
+--
+-- * 'discreteRepCurrency'
+-- * 'discreteRepScaleNumerator'
+-- * 'discreteRepScaleDenominator'
+-- * 'discreteRepAmount'
+data DiscreteRep = DiscreteRep
+  { _discreteRepCurrency         :: !String   -- ^ Currency name.
+  , _discreteRepScaleNumerator   :: !Integer  -- ^ Positive, non-zero.
+  , _discreteRepScaleDenominator :: !Integer  -- ^ Positive, non-zero.
+  , _discreteRepAmount           :: !Integer  -- ^ Amount of unit.
+  } deriving (Eq, Show, GHC.Generic)
+
+-- | WARNING: This instance does not compare monetary amounts, it just helps you
+-- sort 'DiscreteRep' values in case you need to put them in a 'Data.Set.Set' or
+-- similar.
+deriving instance Ord DiscreteRep
+
+-- | Currency name.
+discreteRepCurrency :: DiscreteRep -> String
+discreteRepCurrency = _discreteRepCurrency
+{-# INLINABLE discreteRepCurrency #-}
+
+-- | Positive, non-zero.
+discreteRepScaleNumerator :: DiscreteRep -> Integer
+discreteRepScaleNumerator = _discreteRepScaleNumerator
+{-# INLINABLE discreteRepScaleNumerator #-}
+
+-- | Positive, non-zero.
+discreteRepScaleDenominator :: DiscreteRep -> Integer
+discreteRepScaleDenominator = _discreteRepScaleDenominator
+{-# INLINABLE discreteRepScaleDenominator #-}
+
+-- | Amount of currency unit.
+discreteRepAmount :: DiscreteRep -> Integer
+discreteRepAmount = _discreteRepAmount
+{-# INLINABLE discreteRepAmount #-}
+
+-- | Positive, non-zero.
+discreteRepScale :: DiscreteRep -> Rational
+discreteRepScale = \dr ->
+  discreteRepScaleNumerator dr % discreteRepScaleDenominator dr
+{-# INLINABLE discreteRepScale #-}
+
+
+-- | Internal. Build a 'DiscreteRep' from raw values.
+--
+-- This function is intended for deserialization purposes. You need to convert
+-- this 'DiscreteRep' value to a 'Discrete' vallue in order to do any arithmetic
+-- operation on the monetary value.
+mkDiscreteRep
+  :: String   -- ^ Currency name. ('discreteRepCurrency')
+  -> Integer  -- ^ Scale numerator. Positive, non-zero. ('discreteRepScaleNumerator')
+  -> Integer  -- ^ Scale denominator. Positive, non-zero. ('discreteRepScaleDenominator')
+  -> Integer  -- ^ Amount of unit. ('discreteRepAmount')
+  -> Maybe DiscreteRep
+mkDiscreteRep = \c n d a -> case (n > 0) && (d > 0) of
+  False -> Nothing
+  True -> Just (DiscreteRep c n d a)
+{-# INLINABLE mkDiscreteRep #-}
+
+-- | Convert a 'Discrete' to a 'DiscreteRep' for ease of serialization.
+toDiscreteRep
+  :: (KnownSymbol currency, GoodScale scale)
+  => Discrete' currency scale
+  -> DiscreteRep -- ^
+toDiscreteRep = \(Discrete i0 :: Discrete' currency scale) ->
+  let c = symbolVal (Proxy :: Proxy currency)
+      n = natVal (Proxy :: Proxy (Fst scale))
+      d = natVal (Proxy :: Proxy (Snd scale))
+  in DiscreteRep c n d i0
+{-# INLINABLE toDiscreteRep #-}
+
+-- | Attempt to convert a 'DiscreteRep' to a 'Discrete', provided you know the
+-- target @currency@ and @unit@.
+fromDiscreteRep
+  :: forall currency scale
+  .  (KnownSymbol currency, GoodScale scale)
+  => DiscreteRep
+  -> Maybe (Discrete' currency scale)  -- ^
+fromDiscreteRep = \dr ->
+   if (discreteRepCurrency dr == symbolVal (Proxy :: Proxy currency)) &&
+      (discreteRepScaleNumerator dr == natVal (Proxy :: Proxy (Fst scale))) &&
+      (discreteRepScaleDenominator dr == natVal (Proxy :: Proxy (Snd scale)))
+   then Just (Discrete (discreteRepAmount dr))
+   else Nothing
+{-# INLINABLE fromDiscreteRep #-}
+
+-- | Convert a 'DiscreteRep' to a 'Discrete' without knowing the target
+-- @currency@ and @unit@.
+--
+-- Notice that @currency@ and @unit@ here can't leave its intended scope unless
+-- you can prove equality with some other type at the outer scope, but in that
+-- case you would be better off using 'fromDiscreteRep' directly.
+--
+-- Notice that you may need to add an explicit type to the result of this
+-- function in order to keep the compiler happy.
+withDiscreteRep
+  :: forall r
+  .  DiscreteRep
+  -> ( forall currency scale.
+         ( KnownSymbol currency
+         , GoodScale scale
+         ) => Discrete' currency scale
+           -> r )
+  -> r  -- ^
+withDiscreteRep dr = \f ->
+  case someSymbolVal (discreteRepCurrency dr) of
+    SomeSymbol (Proxy :: Proxy currency) ->
+      case someNatVal (discreteRepScaleNumerator dr) of
+        Nothing -> error "withDiscreteRep: impossible: numerator < 0"
+        Just (SomeNat (Proxy :: Proxy num)) ->
+          case someNatVal (discreteRepScaleDenominator dr) of
+            Nothing -> error "withDiscreteRep: impossible: denominator < 0"
+            Just (SomeNat (Proxy :: Proxy den)) ->
+              case mkGoodScale of
+                Nothing -> error "withDiscreteRep: impossible: mkGoodScale"
+                Just (Dict :: Dict (GoodScale '(num, den))) ->
+                  f (Discrete (discreteRepAmount dr)
+                       :: Discrete' currency '(num, den))
+{-# INLINABLE withDiscreteRep #-}
+
+--------------------------------------------------------------------------------
+-- ExchangeRateRep
+
+-- | A monomorphic representation of 'ExchangeRate' that is easier to serialize
+-- and deserialize than 'ExchangeRate' in case you don't know the type indexes
+-- involved.
+--
+-- If you are trying to construct a value of this type from some raw input, then
+-- you will need to use the 'mkExchangeRateRep' function.
+--
+-- In order to be able to effectively serialize an 'ExchangeRateRep' value, you
+-- need to serialize the following four values (which are the eventual arguments
+-- to 'mkExchangeRateRep'):
+--
+-- * 'exchangeRateRepSrcCurrency'
+-- * 'exchangeRateRepDstCurrency'
+-- * 'exchangeRateRepRateNumerator'
+-- * 'exchangeRateRepRateDenominator'
+data ExchangeRateRep = ExchangeRateRep
+  { _exchangeRateRepSrcCurrency     :: !String
+  , _exchangeRateRepDstCurrency     :: !String
+  , _exchangeRateRepRateNumerator   :: !Integer  -- ^ Positive, non-zero.
+  , _exchangeRateRepRateDenominator :: !Integer  -- ^ Positive, non-zero.
+  } deriving (Eq, Show, GHC.Generic)
+
+-- | WARNING: This instance does not compare monetary amounts, it just helps you
+-- sort 'ExchangeRateRep' values in case you need to put them in a
+-- 'Data.Set.Set' or similar.
+deriving instance Ord ExchangeRateRep
+
+-- | Source currency name.
+exchangeRateRepSrcCurrency :: ExchangeRateRep -> String
+exchangeRateRepSrcCurrency = _exchangeRateRepSrcCurrency
+{-# INLINABLE exchangeRateRepSrcCurrency #-}
+
+-- | Destination currency name.
+exchangeRateRepDstCurrency :: ExchangeRateRep -> String
+exchangeRateRepDstCurrency = _exchangeRateRepDstCurrency
+{-# INLINABLE exchangeRateRepDstCurrency #-}
+
+-- | Exchange rate. Positive, non-zero.
+exchangeRateRepRate :: ExchangeRateRep -> Rational
+exchangeRateRepRate = \x ->
+  exchangeRateRepRateNumerator x % _exchangeRateRepRateDenominator x
+{-# INLINABLE exchangeRateRepRate #-}
+
+-- | Exchange rate numerator. Positive, non-zero.
+exchangeRateRepRateNumerator :: ExchangeRateRep -> Integer
+exchangeRateRepRateNumerator = _exchangeRateRepRateNumerator
+{-# INLINABLE exchangeRateRepRateNumerator #-}
+
+-- | Exchange rate denominator. Positive, non-zero.
+exchangeRateRepRateDenominator :: ExchangeRateRep -> Integer
+exchangeRateRepRateDenominator = _exchangeRateRepRateDenominator
+{-# INLINABLE exchangeRateRepRateDenominator #-}
+
+-- | Internal. Build a 'ExchangeRateRep' from raw values.
+--
+-- This function is intended for deserialization purposes. You need to convert
+-- this 'ExchangeRateRep' value to a 'ExchangeRate' value in order to do any
+-- arithmetic operation with the exchange rate.
+mkExchangeRateRep
+  :: String   -- ^ Source currency name. ('exchangeRateRepSrcCurrency')
+  -> String   -- ^ Destination currency name. ('exchangeRateRepDstCurrency')
+  -> Integer  -- ^ Exchange rate numerator. Positive, non-zero. ('exchangeRateRepRateNumerator')
+  -> Integer  -- ^ Exchange rate denominator. Positive, non-zero. ('exchangeRateRepRateDenominator')
+  -> Maybe ExchangeRateRep
+mkExchangeRateRep = \src dst n d -> case (n > 0) && (d > 0) of
+  False -> Nothing
+  True -> Just (ExchangeRateRep src dst n d)
+{-# INLINABLE mkExchangeRateRep #-}
+
+-- | Convert a 'ExchangeRate' to a 'DiscreteRep' for ease of serialization.
+toExchangeRateRep
+  :: (KnownSymbol src, KnownSymbol dst)
+  => ExchangeRate src dst
+  -> ExchangeRateRep -- ^
+toExchangeRateRep = \(ExchangeRate r0 :: ExchangeRate src dst) ->
+  let src = symbolVal (Proxy :: Proxy src)
+      dst = symbolVal (Proxy :: Proxy dst)
+  in ExchangeRateRep src dst (numerator r0) (denominator r0)
+{-# INLINABLE toExchangeRateRep #-}
+
+-- | Attempt to convert a 'ExchangeRateRep' to a 'ExchangeRate', provided you
+-- know the target @src@ and @dst@ types.
+fromExchangeRateRep
+  :: forall src dst
+  .  (KnownSymbol src, KnownSymbol dst)
+  => ExchangeRateRep
+  -> Maybe (ExchangeRate src dst)  -- ^
+fromExchangeRateRep = \x ->
+   if (exchangeRateRepSrcCurrency x == symbolVal (Proxy :: Proxy src)) &&
+      (exchangeRateRepDstCurrency x == symbolVal (Proxy :: Proxy dst))
+   then Just (ExchangeRate (exchangeRateRepRate x))
+   else Nothing
+{-# INLINABLE fromExchangeRateRep #-}
+
+-- | Convert a 'ExchangeRateRep' to a 'ExchangeRate' without knowing the target
+-- @currency@ and @unit@.
+--
+-- Notice that @src@ and @dst@ here can't leave its intended scope unless
+-- you can prove equality with some other type at the outer scope, but in that
+-- case you would be better off using 'fromExchangeRateRep' directly.
+withExchangeRateRep
+  :: ExchangeRateRep
+  -> ( forall src dst.
+         ( KnownSymbol src
+         , KnownSymbol dst
+         ) => ExchangeRate src dst
+           -> r )
+  -> r  -- ^
+withExchangeRateRep x = \f ->
+  case someSymbolVal (exchangeRateRepSrcCurrency x) of
+    SomeSymbol (Proxy :: Proxy src) ->
+      case someSymbolVal (exchangeRateRepDstCurrency x) of
+        SomeSymbol (Proxy :: Proxy dst) ->
+          f (ExchangeRate (exchangeRateRepRate x) :: ExchangeRate src dst)
+{-# INLINABLE withExchangeRateRep #-}
+
+--------------------------------------------------------------------------------
+-- Miscellaneous
+
+type family Fst (ab :: (ka, kb)) :: ka where Fst '(a,b) = a
+type family Snd (ab :: (ka, kb)) :: ka where Snd '(a,b) = b
+
+--------------------------------------------------------------------------------
+-- Extra instances: hashable
+#ifdef VERSION_hashable
+instance Hashable (Dense currency)
+instance Hashable DenseRep
+instance GoodScale scale => Hashable (Discrete' currency scale)
+instance Hashable DiscreteRep
+instance Hashable (ExchangeRate src dst)
+instance Hashable ExchangeRateRep
+#endif
+
+--------------------------------------------------------------------------------
+-- Extra instances: deepseq
+#ifdef VERSION_deepseq
+instance NFData (Dense currency)
+instance NFData DenseRep
+instance GoodScale scale => NFData (Discrete' currency scale)
+instance NFData DiscreteRep
+instance NFData (ExchangeRate src dst)
+instance NFData ExchangeRateRep
+#endif
+
+--------------------------------------------------------------------------------
+-- Extra instances: cereal
+#ifdef VERSION_cereal
+-- | Compatible with 'DenseRep'.
+instance (KnownSymbol currency) => Cereal.Serialize (Dense currency) where
+  put = Cereal.put . toDenseRep
+  get = maybe empty pure =<< fmap fromDenseRep Cereal.get
+-- | Compatible with 'DiscreteRep'.
+instance
+  ( KnownSymbol currency, GoodScale scale
+  ) => Cereal.Serialize (Discrete' currency scale) where
+  put = Cereal.put . toDiscreteRep
+  get = maybe empty pure =<< fmap fromDiscreteRep Cereal.get
+-- | Compatible with 'ExchangeRateRep'.
+instance
+  ( KnownSymbol src, KnownSymbol dst
+  ) => Cereal.Serialize (ExchangeRate src dst) where
+  put = Cereal.put . toExchangeRateRep
+  get = maybe empty pure =<< fmap fromExchangeRateRep Cereal.get
+-- | Compatible with 'Dense'.
+instance Cereal.Serialize DenseRep where
+  put = \(DenseRep c n d) -> Cereal.put c >> Cereal.put n >> Cereal.put d
+  get = maybe empty pure =<< mkDenseRep
+    <$> Cereal.get <*> Cereal.get <*> Cereal.get
+-- | Compatible with 'Discrete'.
+instance Cereal.Serialize DiscreteRep where
+  put = \(DiscreteRep c n d a) ->
+    Cereal.put c >> Cereal.put n >> Cereal.put d >> Cereal.put a
+  get = maybe empty pure =<< mkDiscreteRep
+    <$> Cereal.get <*> Cereal.get <*> Cereal.get <*> Cereal.get
+-- | Compatible with 'ExchangeRate'.
+instance Cereal.Serialize ExchangeRateRep where
+  put = \(ExchangeRateRep src dst n d) ->
+    Cereal.put src >> Cereal.put dst >> Cereal.put n >> Cereal.put d
+  get = maybe empty pure =<< mkExchangeRateRep
+    <$> Cereal.get <*> Cereal.get <*> Cereal.get <*> Cereal.get
+#endif
+
+--------------------------------------------------------------------------------
+-- Extra instances: binary
+#ifdef VERSION_binary
+-- | Compatible with 'DenseRep'.
+instance (KnownSymbol currency) => Binary.Binary (Dense currency) where
+  put = Binary.put . toDenseRep
+  get = maybe empty pure =<< fmap fromDenseRep Binary.get
+-- | Compatible with 'DiscreteRep'.
+instance
+  ( KnownSymbol currency, GoodScale scale
+  ) => Binary.Binary (Discrete' currency scale) where
+  put = Binary.put . toDiscreteRep
+  get = maybe empty pure =<< fmap fromDiscreteRep Binary.get
+-- | Compatible with 'ExchangeRateRep'.
+instance
+  ( KnownSymbol src, KnownSymbol dst
+  ) => Binary.Binary (ExchangeRate src dst) where
+  put = Binary.put . toExchangeRateRep
+  get = maybe empty pure =<< fmap fromExchangeRateRep Binary.get
+-- | Compatible with 'Dense'.
+instance Binary.Binary DenseRep where
+  put = \(DenseRep c n d) -> Binary.put c >> Binary.put n >> Binary.put d
+  get = maybe empty pure =<< mkDenseRep
+    <$> Binary.get <*> Binary.get <*> Binary.get
+-- | Compatible with 'Discrete'.
+instance Binary.Binary DiscreteRep where
+  put = \(DiscreteRep c n d a) ->
+    Binary.put c >> Binary.put n >> Binary.put d >> Binary.put a
+  get = maybe empty pure =<< mkDiscreteRep
+    <$> Binary.get <*> Binary.get <*> Binary.get <*> Binary.get
+-- | Compatible with 'ExchangeRate'.
+instance Binary.Binary ExchangeRateRep where
+  put = \(ExchangeRateRep src dst n d) ->
+    Binary.put src >> Binary.put dst >> Binary.put n >> Binary.put d
+  get = maybe empty pure =<< mkExchangeRateRep
+    <$> Binary.get <*> Binary.get <*> Binary.get <*> Binary.get
+#endif
+
+--------------------------------------------------------------------------------
+-- Extra instances: aeson
+#ifdef VERSION_aeson
+-- | Compatible with 'DenseRep'
+instance KnownSymbol currency => Ae.ToJSON (Dense currency) where
+  toJSON = Ae.toJSON . toDenseRep
+-- | Compatible with 'DenseRep'
+instance KnownSymbol currency => Ae.FromJSON (Dense currency) where
+  parseJSON = maybe empty pure <=< fmap fromDenseRep . Ae.parseJSON
+-- | Compatible with 'Dense'
+instance Ae.ToJSON DenseRep where
+  toJSON = \(DenseRep c n d) -> Ae.toJSON ("Dense", c, n, d)
+-- | Compatible with 'Dense'
+instance Ae.FromJSON DenseRep where
+  parseJSON = \v -> do
+    ("Dense", c, n, d) <- Ae.parseJSON v
+    maybe empty pure (mkDenseRep c n d)
+-- | Compatible with 'DiscreteRep'
+instance
+  ( KnownSymbol currency, GoodScale scale
+  ) => Ae.ToJSON (Discrete' currency scale) where
+  toJSON = Ae.toJSON . toDiscreteRep
+-- | Compatible with 'DiscreteRep'
+instance
+  ( KnownSymbol currency, GoodScale scale
+  ) => Ae.FromJSON (Discrete' currency scale) where
+  parseJSON = maybe empty pure <=< fmap fromDiscreteRep . Ae.parseJSON
+-- | Compatible with 'Discrete''
+instance Ae.ToJSON DiscreteRep where
+  toJSON = \(DiscreteRep c n d a) -> Ae.toJSON ("Discrete", c, n, d, a)
+-- | Compatible with 'Discrete''
+instance Ae.FromJSON DiscreteRep where
+  parseJSON = \v -> do
+    ("Discrete", c, n, d, a) <- Ae.parseJSON v
+    maybe empty pure (mkDiscreteRep c n d a)
+-- | Compatible with 'ExchangeRateRep'
+instance
+  ( KnownSymbol src, KnownSymbol dst
+  ) => Ae.ToJSON (ExchangeRate src dst) where
+  toJSON = Ae.toJSON . toExchangeRateRep
+-- | Compatible with 'ExchangeRateRep'
+instance
+  ( KnownSymbol src, KnownSymbol dst
+  ) => Ae.FromJSON (ExchangeRate src dst) where
+  parseJSON = maybe empty pure <=< fmap fromExchangeRateRep . Ae.parseJSON
+-- | Compatible with 'ExchangeRate'
+instance Ae.ToJSON ExchangeRateRep where
+  toJSON = \(ExchangeRateRep src dst n d) ->
+    Ae.toJSON ("ExchangeRate", src, dst, n, d)
+-- | Compatible with 'ExchangeRate'
+instance Ae.FromJSON ExchangeRateRep where
+  parseJSON = \v -> do
+    ("ExchangeRate", src, dst, n, d) <- Ae.parseJSON v
+    maybe empty pure (mkExchangeRateRep src dst n d)
+#endif
+
+--------------------------------------------------------------------------------
+-- Extra instances: store
+#ifdef VERSION_store
+-- | Compatible with 'DenseRep'.
+instance (KnownSymbol currency) => Store.Store (Dense currency) where
+  size = storeContramapSize toDenseRep Store.size
+  poke = Store.poke . toDenseRep
+  peek = maybe (fail "peek") pure =<< fmap fromDenseRep Store.peek
+-- | Compatible with 'Dense'.
+instance Store.Store DenseRep where
+  poke = \(DenseRep c n d) -> Store.poke c >> Store.poke n >> Store.poke d
+  peek = maybe (fail "peek") pure =<< do
+    mkDenseRep <$> Store.peek <*> Store.peek <*> Store.peek
+
+-- | Compatible with 'DiscreteRep'.
+instance
+  ( KnownSymbol currency, GoodScale scale
+  ) => Store.Store (Discrete' currency scale) where
+  size = storeContramapSize toDiscreteRep Store.size
+  poke = Store.poke . toDiscreteRep
+  peek = maybe (fail "peek") pure =<< fmap fromDiscreteRep Store.peek
+-- | Compatible with 'Discrete''.
+instance Store.Store DiscreteRep where
+  poke = \(DiscreteRep c n d a) ->
+    Store.poke c >> Store.poke n >> Store.poke d >> Store.poke a
+  peek = maybe (fail "peek") pure =<< do
+    mkDiscreteRep <$> Store.peek <*> Store.peek <*> Store.peek <*> Store.peek
+-- | Compatible with 'ExchangeRateRep'.
+instance
+  ( KnownSymbol src, KnownSymbol dst
+  ) => Store.Store (ExchangeRate src dst) where
+  size = storeContramapSize toExchangeRateRep Store.size
+  poke = Store.poke . toExchangeRateRep
+  peek = maybe (fail "peek") pure =<< fmap fromExchangeRateRep Store.peek
+-- | Compatible with 'ExchangeRate'.
+instance Store.Store ExchangeRateRep where
+  poke = \(ExchangeRateRep src dst n d) ->
+    Store.poke src >> Store.poke dst >> Store.poke n >> Store.poke d
+  peek = maybe (fail "peek") pure =<< mkExchangeRateRep
+    <$> Store.peek <*> Store.peek <*> Store.peek <*> Store.peek
+
+storeContramapSize :: (a -> b) -> Store.Size b -> Store.Size a
+storeContramapSize f = \case
+  Store.VarSize g -> Store.VarSize (g . f)
+  Store.ConstSize x -> Store.ConstSize x
+{-# INLINABLE storeContramapSize #-}
+#endif
diff --git a/test/Main.hs b/test/Main.hs
new file mode 100644
--- /dev/null
+++ b/test/Main.hs
@@ -0,0 +1,453 @@
+{-# LANGUAGE CPP #-}
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE PolyKinds #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE UndecidableInstances #-}
+{-# LANGUAGE TypeFamilies #-}
+
+module Main where
+
+import qualified Test.Tasty as Tasty
+import qualified Test.Tasty.Runners as Tasty
+import Test.Tasty.QuickCheck ((===), (==>))
+import qualified Test.Tasty.QuickCheck as QC
+
+import qualified Data.Aeson as Ae
+import qualified Data.Binary as Binary
+import qualified Data.ByteString.Lazy as BSL
+import Data.Maybe (catMaybes, isJust, isNothing)
+import Data.Proxy (Proxy(Proxy))
+import qualified Data.Serialize as Cereal
+import GHC.TypeLits (Nat, Symbol, KnownSymbol, symbolVal)
+
+#ifdef VERSION_store
+import qualified Data.Store as Store
+#endif
+
+import qualified Money
+
+--------------------------------------------------------------------------------
+
+instance
+  ( Money.GoodScale scale
+  ) => QC.Arbitrary (Money.Discrete' currency scale) where
+  arbitrary = fmap fromInteger QC.arbitrary
+  shrink = fmap fromInteger . QC.shrink . toInteger
+
+instance QC.Arbitrary Money.DiscreteRep where
+  arbitrary = do
+    let md = Money.mkDiscreteRep <$> QC.arbitrary <*> QC.arbitrary
+                                 <*> QC.arbitrary <*> QC.arbitrary
+    Just x <- QC.suchThat md isJust
+    pure x
+  shrink = \x -> Money.withDiscreteRep x (map Money.toDiscreteRep . QC.shrink)
+
+instance QC.Arbitrary (Money.Dense currency) where
+  arbitrary = do
+    Just x <- QC.suchThat (Money.dense <$> QC.arbitrary) isJust
+    pure x
+  shrink = catMaybes . fmap Money.dense . QC.shrink . toRational
+
+instance QC.Arbitrary Money.DenseRep where
+  arbitrary = do
+    let md = Money.mkDenseRep <$> QC.arbitrary <*> QC.arbitrary <*> QC.arbitrary
+    Just x <- QC.suchThat md isJust
+    pure x
+  shrink = \x -> Money.withDenseRep x (map Money.toDenseRep . QC.shrink)
+
+instance QC.Arbitrary (Money.ExchangeRate src dst) where
+  arbitrary = do
+    Just x <- QC.suchThat (fmap Money.exchangeRate QC.arbitrary) isJust
+    pure x
+  shrink =
+    catMaybes . fmap Money.exchangeRate . QC.shrink . Money.fromExchangeRate
+
+instance QC.Arbitrary Money.ExchangeRateRep where
+  arbitrary = do
+    let md = Money.mkExchangeRateRep <$> QC.arbitrary <*> QC.arbitrary
+                                     <*> QC.arbitrary <*> QC.arbitrary
+    Just x <- QC.suchThat md isJust
+    pure x
+  shrink = \x ->
+    Money.withExchangeRateRep x (map Money.toExchangeRateRep . QC.shrink)
+
+--------------------------------------------------------------------------------
+
+main :: IO ()
+main =  Tasty.defaultMainWithIngredients
+  [ Tasty.consoleTestReporter
+  , Tasty.listingTests
+  ] tests
+
+tests :: Tasty.TestTree
+tests =
+  Tasty.testGroup "root"
+  [ testCurrencies
+  , testCurrencyUnits
+  , testExchange
+  ]
+
+testCurrencies :: Tasty.TestTree
+testCurrencies =
+  Tasty.testGroup "Currency"
+  [ testDense (Proxy :: Proxy "BTC")  -- A cryptocurrency.
+  , testDense (Proxy :: Proxy "USD")  -- A fiat currency with decimal fractions.
+  , testDense (Proxy :: Proxy "VUV")  -- A fiat currency with non-decimal fractions.
+  , testDense (Proxy :: Proxy "XAU")  -- A precious metal.
+  ]
+
+testCurrencyUnits :: Tasty.TestTree
+testCurrencyUnits =
+  Tasty.testGroup "Currency units"
+  [ testDiscrete (Proxy :: Proxy "BTC") (Proxy :: Proxy "BTC")
+  , testDiscrete (Proxy :: Proxy "BTC") (Proxy :: Proxy "satoshi")
+  , testDiscrete (Proxy :: Proxy "BTC") (Proxy :: Proxy "bitcoin")
+  , testDiscrete (Proxy :: Proxy "USD") (Proxy :: Proxy "USD")
+  , testDiscrete (Proxy :: Proxy "USD") (Proxy :: Proxy "cent")
+  , testDiscrete (Proxy :: Proxy "USD") (Proxy :: Proxy "dollar")
+  , testDiscrete (Proxy :: Proxy "VUV") (Proxy :: Proxy "vatu")
+  , testDiscrete (Proxy :: Proxy "XAU") (Proxy :: Proxy "micrograin")
+  , testDiscrete (Proxy :: Proxy "XAU") (Proxy :: Proxy "milligrain")
+  , testDiscrete (Proxy :: Proxy "XAU") (Proxy :: Proxy "grain")
+  ]
+
+testDense
+  :: forall currency
+  .  KnownSymbol currency
+  => Proxy currency
+  -> Tasty.TestTree
+testDense pc =
+  Tasty.testGroup ("Dense " ++ show (symbolVal pc))
+  [ QC.testProperty "read . show == id" $
+      QC.forAll QC.arbitrary $ \(x :: Money.Dense currency) ->
+         x === read (show x)
+  , QC.testProperty "fromDenseRep . denseRep == Just" $
+      QC.forAll QC.arbitrary $ \(x :: Money.Dense currency) ->
+         Just x === Money.fromDenseRep (Money.toDenseRep x)
+  , QC.testProperty "fromDenseRep works only for same currency" $
+      QC.forAll QC.arbitrary $ \(dr :: Money.DenseRep) ->
+        (Money.denseRepCurrency dr /= symbolVal pc)
+           ==> isNothing (Money.fromDenseRep dr :: Maybe (Money.Dense currency))
+  , QC.testProperty "withDenseRep" $
+      QC.forAll QC.arbitrary $ \(x :: Money.Dense currency) ->
+        let dr = Money.toDenseRep x
+        in Money.withDenseRep dr $ \x' ->
+             (show x, dr, Money.toDenseRep (x + 1))
+                === (show x', Money.toDenseRep x', Money.toDenseRep (x' + 1))
+
+  , QC.testProperty "Aeson encoding roundtrip" $
+      QC.forAll QC.arbitrary $ \(x :: Money.Dense currency) ->
+         Just x === Ae.decode (Ae.encode x)
+  , QC.testProperty "Aeson encoding roundtrip (DenseRep)" $
+      QC.forAll QC.arbitrary $ \(x :: Money.Dense currency) ->
+         let x' = Money.toDenseRep x
+         in Just x' === Ae.decode (Ae.encode x')
+  , QC.testProperty "Aeson encoding roundtrip (Dense through DenseRep)" $
+      QC.forAll QC.arbitrary $ \(x :: Money.Dense currency) ->
+         Just x === Ae.decode (Ae.encode (Money.toDenseRep x))
+  , QC.testProperty "Aeson encoding roundtrip (DenseRep through Dense)" $
+      QC.forAll QC.arbitrary $ \(x :: Money.Dense currency) ->
+         Just (Money.toDenseRep x) === Ae.decode (Ae.encode x)
+
+  , QC.testProperty "Binary encoding roundtrip" $
+      QC.forAll QC.arbitrary $ \(x :: Money.Dense currency) ->
+         let Right (_,_,y) = Binary.decodeOrFail (Binary.encode x)
+         in x === y
+  , QC.testProperty "Binary encoding roundtrip (DenseRep)" $
+      QC.forAll QC.arbitrary $ \(x :: Money.Dense currency) ->
+         let x' = Money.toDenseRep x
+             bs = Binary.encode x'
+         in Right (mempty, BSL.length bs, x') === Binary.decodeOrFail bs
+  , QC.testProperty "Binary encoding roundtrip (Dense through DenseRep)" $
+      QC.forAll QC.arbitrary $ \(x :: Money.Dense currency) ->
+         let x' = Money.toDenseRep x
+             bs = Binary.encode x'
+         in Right (mempty, BSL.length bs, x) === Binary.decodeOrFail bs
+  , QC.testProperty "Binary encoding roundtrip (DenseRep through Dense)" $
+      QC.forAll QC.arbitrary $ \(x :: Money.Dense currency) ->
+         let x' = Money.toDenseRep x
+             bs = Binary.encode x
+         in Right (mempty, BSL.length bs, x') === Binary.decodeOrFail bs
+
+  , QC.testProperty "Cereal encoding roundtrip" $
+      QC.forAll QC.arbitrary $ \(x :: Money.Dense currency) ->
+         Right x === Cereal.decode (Cereal.encode x)
+  , QC.testProperty "Cereal encoding roundtrip (DenseRep)" $
+      QC.forAll QC.arbitrary $ \(x :: Money.Dense currency) ->
+         let x' = Money.toDenseRep x
+         in Right x' === Cereal.decode (Cereal.encode x')
+  , QC.testProperty "Cereal encoding roundtrip (Dense through DenseRep)" $
+      QC.forAll QC.arbitrary $ \(x :: Money.Dense currency) ->
+         Right x === Cereal.decode (Cereal.encode (Money.toDenseRep x))
+  , QC.testProperty "Cereal encoding roundtrip (DenseRep through Dense)" $
+      QC.forAll QC.arbitrary $ \(x :: Money.Dense currency) ->
+         Right (Money.toDenseRep x) === Cereal.decode (Cereal.encode x)
+
+#ifdef VERSION_store
+  , QC.testProperty "Store encoding roundtrip" $
+      QC.forAll QC.arbitrary $ \(x :: Money.Dense currency) ->
+         Right x === Store.decode (Store.encode x)
+  , QC.testProperty "Store encoding roundtrip (DenseRep)" $
+      QC.forAll QC.arbitrary $ \(x :: Money.Dense currency) ->
+         let x' = Money.toDenseRep x
+         in Right x' === Store.decode (Store.encode x')
+  , QC.testProperty "Store encoding roundtrip (Dense through DenseRep)" $
+      QC.forAll QC.arbitrary $ \(x :: Money.Dense currency) ->
+         Right x === Store.decode (Store.encode (Money.toDenseRep x))
+  , QC.testProperty "Store encoding roundtrip (DenseRep through Dense)" $
+      QC.forAll QC.arbitrary $ \(x :: Money.Dense currency) ->
+         Right (Money.toDenseRep x) === Store.decode (Store.encode x)
+#endif
+  ]
+
+testExchange :: Tasty.TestTree
+testExchange =
+  Tasty.testGroup "Exchange"
+  [ testExchangeRate (Proxy :: Proxy "BTC") (Proxy :: Proxy "BTC")
+  , testExchangeRate (Proxy :: Proxy "BTC") (Proxy :: Proxy "USD")
+  , testExchangeRate (Proxy :: Proxy "BTC") (Proxy :: Proxy "VUV")
+  , testExchangeRate (Proxy :: Proxy "BTC") (Proxy :: Proxy "XAU")
+  , testExchangeRate (Proxy :: Proxy "USD") (Proxy :: Proxy "BTC")
+  , testExchangeRate (Proxy :: Proxy "USD") (Proxy :: Proxy "USD")
+  , testExchangeRate (Proxy :: Proxy "USD") (Proxy :: Proxy "VUV")
+  , testExchangeRate (Proxy :: Proxy "USD") (Proxy :: Proxy "XAU")
+  , testExchangeRate (Proxy :: Proxy "VUV") (Proxy :: Proxy "BTC")
+  , testExchangeRate (Proxy :: Proxy "VUV") (Proxy :: Proxy "USD")
+  , testExchangeRate (Proxy :: Proxy "VUV") (Proxy :: Proxy "VUV")
+  , testExchangeRate (Proxy :: Proxy "VUV") (Proxy :: Proxy "XAU")
+  , testExchangeRate (Proxy :: Proxy "XAU") (Proxy :: Proxy "BTC")
+  , testExchangeRate (Proxy :: Proxy "XAU") (Proxy :: Proxy "USD")
+  , testExchangeRate (Proxy :: Proxy "XAU") (Proxy :: Proxy "VUV")
+  , testExchangeRate (Proxy :: Proxy "XAU") (Proxy :: Proxy "XAU")
+  ]
+
+testDiscrete
+  :: forall (currency :: Symbol) (unit :: Symbol)
+  .  ( Money.GoodScale (Money.Scale currency unit)
+     , KnownSymbol currency
+     , KnownSymbol unit )
+  => Proxy currency
+  -> Proxy unit
+  -> Tasty.TestTree
+testDiscrete pc pu =
+  Tasty.testGroup ("Discrete " ++ show (symbolVal pc) ++ " "
+                               ++ show (symbolVal pu))
+  [ testRounding pc pu
+  , QC.testProperty "read . show == id" $
+      QC.forAll QC.arbitrary $ \(x :: Money.Discrete currency unit) ->
+         x === read (show x)
+  , QC.testProperty "fromDiscreteRep . discreteRep == Just" $
+      QC.forAll QC.arbitrary $ \(x :: Money.Discrete currency unit) ->
+         Just x === Money.fromDiscreteRep (Money.toDiscreteRep x)
+  , QC.testProperty "fromDiscreteRep works only for same currency and scale" $
+      QC.forAll QC.arbitrary $ \(dr :: Money.DiscreteRep) ->
+        ((Money.discreteRepCurrency dr /= symbolVal pc) &&
+         (Money.discreteRepScale dr /=
+             Money.scale (Proxy :: Proxy (Money.Scale currency unit)))
+        ) ==> isNothing (Money.fromDiscreteRep dr
+                          :: Maybe (Money.Discrete currency unit))
+  , QC.testProperty "withDiscreteRep" $
+      QC.forAll QC.arbitrary $ \(x :: Money.Discrete currency unit) ->
+        let dr = Money.toDiscreteRep x
+        in ( Money.withDiscreteRep dr $ \x' ->
+                (show x, dr, Money.toDiscreteRep (x + 1))
+                   === (show x', Money.toDiscreteRep x', Money.toDiscreteRep (x' + 1))
+           ) :: QC.Property
+
+  , QC.testProperty "Aeson encoding roundtrip" $
+      QC.forAll QC.arbitrary $ \(x :: Money.Discrete currency unit) ->
+         Just x === Ae.decode (Ae.encode x)
+  , QC.testProperty "Aeson encoding roundtrip (DiscreteRep)" $
+      QC.forAll QC.arbitrary $ \(x :: Money.Discrete currency unit) ->
+         let x' = Money.toDiscreteRep x
+         in Just x' === Ae.decode (Ae.encode x')
+  , QC.testProperty "Aeson encoding roundtrip (Discrete through DiscreteRep)" $
+      QC.forAll QC.arbitrary $ \(x :: Money.Discrete currency unit) ->
+         Just x === Ae.decode (Ae.encode (Money.toDiscreteRep x))
+  , QC.testProperty "Aeson encoding roundtrip (DiscreteRep through Discrete)" $
+      QC.forAll QC.arbitrary $ \(x :: Money.Discrete currency unit) ->
+         Just (Money.toDiscreteRep x) === Ae.decode (Ae.encode x)
+
+  , QC.testProperty "Binary encoding roundtrip" $
+      QC.forAll QC.arbitrary $ \(x :: Money.Discrete currency unit) ->
+         let Right (_,_,y) = Binary.decodeOrFail (Binary.encode x)
+         in x === y
+  , QC.testProperty "Binary encoding roundtrip (DiscreteRep)" $
+      QC.forAll QC.arbitrary $ \(x :: Money.Discrete currency unit) ->
+         let x' = Money.toDiscreteRep x
+             bs = Binary.encode x'
+         in Right (mempty, BSL.length bs, x') === Binary.decodeOrFail bs
+  , QC.testProperty "Binary encoding roundtrip (Discrete through DiscreteRep)" $
+      QC.forAll QC.arbitrary $ \(x :: Money.Discrete currency unit) ->
+         let x' = Money.toDiscreteRep x
+             bs = Binary.encode x'
+         in Right (mempty, BSL.length bs, x) === Binary.decodeOrFail bs
+  , QC.testProperty "Binary encoding roundtrip (DiscreteRep through Discrete)" $
+      QC.forAll QC.arbitrary $ \(x :: Money.Discrete currency unit) ->
+         let x' = Money.toDiscreteRep x
+             bs = Binary.encode x
+         in Right (mempty, BSL.length bs, x') === Binary.decodeOrFail bs
+
+  , QC.testProperty "Cereal encoding roundtrip" $
+      QC.forAll QC.arbitrary $ \(x :: Money.Discrete currency unit) ->
+         Right x === Cereal.decode (Cereal.encode x)
+  , QC.testProperty "Cereal encoding roundtrip (DiscreteRep)" $
+      QC.forAll QC.arbitrary $ \(x :: Money.Discrete currency unit) ->
+         let x' = Money.toDiscreteRep x
+         in Right x' === Cereal.decode (Cereal.encode x')
+  , QC.testProperty "Cereal encoding roundtrip (Discrete through DiscreteRep)" $
+      QC.forAll QC.arbitrary $ \(x :: Money.Discrete currency unit) ->
+         Right x === Cereal.decode (Cereal.encode (Money.toDiscreteRep x))
+  , QC.testProperty "Cereal encoding roundtrip (DiscreteRep through Discrete)" $
+      QC.forAll QC.arbitrary $ \(x :: Money.Discrete currency unit) ->
+         Right (Money.toDiscreteRep x) === Cereal.decode (Cereal.encode x)
+
+#ifdef VERSION_store
+  , QC.testProperty "Store encoding roundtrip" $
+      QC.forAll QC.arbitrary $ \(x :: Money.Discrete currency unit) ->
+         Right x === Store.decode (Store.encode x)
+  , QC.testProperty "Store encoding roundtrip (DiscreteRep)" $
+      QC.forAll QC.arbitrary $ \(x :: Money.Discrete currency unit) ->
+         let x' = Money.toDiscreteRep x
+         in Right x' === Store.decode (Store.encode x')
+  , QC.testProperty "Store encoding roundtrip (Discrete through DiscreteRep)" $
+      QC.forAll QC.arbitrary $ \(x :: Money.Discrete currency unit) ->
+         Right x === Store.decode (Store.encode (Money.toDiscreteRep x))
+  , QC.testProperty "Store encoding roundtrip (DiscreteRep through Discrete)" $
+      QC.forAll QC.arbitrary $ \(x :: Money.Discrete currency unit) ->
+         Right (Money.toDiscreteRep x) === Store.decode (Store.encode x)
+#endif
+  ]
+
+testExchangeRate
+  :: forall (src :: Symbol) (dst :: Symbol)
+  .  (KnownSymbol src, KnownSymbol dst)
+  => Proxy src
+  -> Proxy dst
+  -> Tasty.TestTree
+testExchangeRate ps pd =
+  Tasty.testGroup ("ExchangeRate " ++ show (symbolVal ps) ++ " "
+                                   ++ show (symbolVal pd))
+  [ QC.testProperty "read . show == id" $
+      QC.forAll QC.arbitrary $ \(xr :: Money.ExchangeRate src dst) ->
+         xr === read (show xr)
+  , QC.testProperty "flipExchangeRate . flipExchangeRate == id" $
+      QC.forAll QC.arbitrary $ \(xr :: Money.ExchangeRate src dst) ->
+         let xr' = Money.flipExchangeRate xr
+         in (Money.fromExchangeRate xr /= Money.fromExchangeRate xr')
+               ==> (xr === Money.flipExchangeRate xr')
+  , QC.testProperty "exchange (flipExchangeRate x) . exchange x == id" $
+      QC.forAll QC.arbitrary $
+         \( c0 :: Money.Dense src
+          , xr :: Money.ExchangeRate src dst
+          ) -> c0 === Money.exchange (Money.flipExchangeRate xr)
+                                     (Money.exchange xr c0)
+  , QC.testProperty "x == 1 ===> exchange x == id" $
+      QC.forAll QC.arbitrary $
+         \( c0 :: Money.Dense src
+          ) -> let Just xr = Money.exchangeRate 1
+               in toRational c0 === toRational (Money.exchange xr c0)
+  , QC.testProperty "x /= 1 ===> exchange x /= id" $
+      QC.forAll QC.arbitrary $
+         \( c0 :: Money.Dense src
+          , xr :: Money.ExchangeRate src dst
+          ) -> (Money.fromExchangeRate xr /= 1)
+                  ==> (toRational c0 /= toRational (Money.exchange xr c0))
+  , QC.testProperty "fromExchangeRateRep . exchangeRateRep == Just" $
+      QC.forAll QC.arbitrary $ \(x :: Money.ExchangeRate src dst) ->
+         Just x === Money.fromExchangeRateRep (Money.toExchangeRateRep x)
+  , QC.testProperty "fromExchangeRateRep works only for same currencies" $
+      QC.forAll QC.arbitrary $ \(x :: Money.ExchangeRateRep) ->
+        ((Money.exchangeRateRepSrcCurrency x /= symbolVal ps) &&
+         (Money.exchangeRateRepDstCurrency x /= symbolVal pd))
+            ==> isNothing (Money.fromExchangeRateRep x
+                            :: Maybe (Money.ExchangeRate src dst))
+  , QC.testProperty "withExchangeRateRep" $
+      QC.forAll QC.arbitrary $ \(x :: Money.ExchangeRate src dst) ->
+        let dr = Money.toExchangeRateRep x
+        in Money.withExchangeRateRep dr $ \x' ->
+             (show x, dr) === (show x', Money.toExchangeRateRep x')
+
+  , QC.testProperty "Aeson encoding roundtrip" $
+      QC.forAll QC.arbitrary $ \(x :: Money.ExchangeRate src dst) ->
+         Just x === Ae.decode (Ae.encode x)
+  , QC.testProperty "Aeson encoding roundtrip (ExchangeRateRep)" $
+      QC.forAll QC.arbitrary $ \(x :: Money.ExchangeRate src dst) ->
+         let x' = Money.toExchangeRateRep x
+         in Just x' === Ae.decode (Ae.encode x')
+  , QC.testProperty "Aeson encoding roundtrip (ExchangeRate through ExchangeRateRep)" $
+      QC.forAll QC.arbitrary $ \(x :: Money.ExchangeRate src dst) ->
+         Just x === Ae.decode (Ae.encode (Money.toExchangeRateRep x))
+  , QC.testProperty "Aeson encoding roundtrip (ExchangeRateRep through ExchangeRate)" $
+      QC.forAll QC.arbitrary $ \(x :: Money.ExchangeRate src dst) ->
+         Just (Money.toExchangeRateRep x) === Ae.decode (Ae.encode x)
+
+  , QC.testProperty "Binary encoding roundtrip" $
+      QC.forAll QC.arbitrary $ \(x :: Money.ExchangeRate src dst) ->
+         let Right (_,_,y) = Binary.decodeOrFail (Binary.encode x)
+         in x === y
+  , QC.testProperty "Binary encoding roundtrip (ExchangeRateRep)" $
+      QC.forAll QC.arbitrary $ \(x :: Money.ExchangeRate src dst) ->
+         let x' = Money.toExchangeRateRep x
+             bs = Binary.encode x'
+         in Right (mempty, BSL.length bs, x') === Binary.decodeOrFail bs
+  , QC.testProperty "Binary encoding roundtrip (ExchangeRate through ExchangeRateRep)" $
+      QC.forAll QC.arbitrary $ \(x :: Money.ExchangeRate src dst) ->
+         let x' = Money.toExchangeRateRep x
+             bs = Binary.encode x'
+         in Right (mempty, BSL.length bs, x) === Binary.decodeOrFail bs
+  , QC.testProperty "Binary encoding roundtrip (ExchangeRateRep through ExchangeRate)" $
+      QC.forAll QC.arbitrary $ \(x :: Money.ExchangeRate src dst) ->
+         let x' = Money.toExchangeRateRep x
+             bs = Binary.encode x
+         in Right (mempty, BSL.length bs, x') === Binary.decodeOrFail bs
+
+  , QC.testProperty "Cereal encoding roundtrip" $
+      QC.forAll QC.arbitrary $ \(x :: Money.ExchangeRate src dst) ->
+         Right x === Cereal.decode (Cereal.encode x)
+  , QC.testProperty "Cereal encoding roundtrip (ExchangeRateRep)" $
+      QC.forAll QC.arbitrary $ \(x :: Money.ExchangeRate src dst) ->
+         let x' = Money.toExchangeRateRep x
+         in Right x' === Cereal.decode (Cereal.encode x')
+  , QC.testProperty "Cereal encoding roundtrip (ExchangeRate through ExchangeRateRep)" $
+      QC.forAll QC.arbitrary $ \(x :: Money.ExchangeRate src dst) ->
+         Right x === Cereal.decode (Cereal.encode (Money.toExchangeRateRep x))
+  , QC.testProperty "Cereal encoding roundtrip (ExchangeRateRep through ExchangeRate)" $
+      QC.forAll QC.arbitrary $ \(x :: Money.ExchangeRate src dst) ->
+         Right (Money.toExchangeRateRep x) === Cereal.decode (Cereal.encode x)
+
+#ifdef VERSION_store
+  , QC.testProperty "Store encoding roundtrip" $
+      QC.forAll QC.arbitrary $ \(x :: Money.ExchangeRate src dst) ->
+         Right x === Store.decode (Store.encode x)
+  , QC.testProperty "Store encoding roundtrip (ExchangeRateRep)" $
+      QC.forAll QC.arbitrary $ \(x :: Money.ExchangeRate src dst) ->
+         let x' = Money.toExchangeRateRep x
+         in Right x' === Store.decode (Store.encode x')
+  , QC.testProperty "Store encoding roundtrip (ExchangeRate through ExchangeRateRep)" $
+      QC.forAll QC.arbitrary $ \(x :: Money.ExchangeRate src dst) ->
+         Right x === Store.decode (Store.encode (Money.toExchangeRateRep x))
+  , QC.testProperty "Store encoding roundtrip (ExchangeRateRep through ExchangeRate)" $
+      QC.forAll QC.arbitrary $ \(x :: Money.ExchangeRate src dst) ->
+         Right (Money.toExchangeRateRep x) === Store.decode (Store.encode x)
+#endif
+  ]
+
+testRounding
+  :: forall (currency :: Symbol) (unit :: Symbol)
+  .  (Money.GoodScale (Money.Scale currency unit), KnownSymbol currency)
+  => Proxy currency
+  -> Proxy unit
+  -> Tasty.TestTree
+testRounding _ _ =
+    Tasty.testGroup "Rounding"
+    [ QC.testProperty "floor"    $ QC.forAll QC.arbitrary (g Money.floor)
+    , QC.testProperty "ceiling"  $ QC.forAll QC.arbitrary (g Money.ceiling)
+    , QC.testProperty "round"    $ QC.forAll QC.arbitrary (g Money.round)
+    , QC.testProperty "truncate" $ QC.forAll QC.arbitrary (g Money.truncate)
+    ]
+  where
+    g f = \(x :: Money.Dense currency) -> x === case f x of
+      (y, Nothing) -> Money.fromDiscrete (y :: Money.Discrete currency unit)
+      (y, Just z)  -> Money.fromDiscrete y + z
diff --git a/tests/Main.hs b/tests/Main.hs
deleted file mode 100644
--- a/tests/Main.hs
+++ /dev/null
@@ -1,444 +0,0 @@
-{-# LANGUAGE DataKinds #-}
-{-# LANGUAGE FlexibleContexts #-}
-{-# LANGUAGE PolyKinds #-}
-{-# LANGUAGE ScopedTypeVariables #-}
-{-# LANGUAGE UndecidableInstances #-}
-{-# LANGUAGE TypeFamilies #-}
-
-module Main where
-
-import qualified Test.Tasty as Tasty
-import qualified Test.Tasty.Runners as Tasty
-import Test.Tasty.QuickCheck ((===), (==>))
-import qualified Test.Tasty.QuickCheck as QC
-
-import qualified Data.Aeson as Ae
-import qualified Data.Binary as Binary
-import qualified Data.ByteString.Lazy as BSL
-import Data.Maybe (catMaybes, isJust, isNothing)
-import Data.Proxy (Proxy(Proxy))
-import qualified Data.Serialize as Cereal
-import qualified Data.Store as Store
-import GHC.TypeLits (Nat, Symbol, KnownSymbol, symbolVal)
-
-import qualified Data.Money as Money
-import qualified Data.Money.Internal as Money
-
---------------------------------------------------------------------------------
-
-instance
-  ( Money.GoodScale scale
-  ) => QC.Arbitrary (Money.Discrete' currency scale) where
-  arbitrary = fmap fromInteger QC.arbitrary
-  shrink = fmap fromInteger . QC.shrink . toInteger
-
-instance QC.Arbitrary Money.DiscreteRep where
-  arbitrary = do
-    let md = Money.mkDiscreteRep <$> QC.arbitrary <*> QC.arbitrary
-                                 <*> QC.arbitrary <*> QC.arbitrary
-    Just x <- QC.suchThat md isJust
-    pure x
-  shrink = \x -> Money.withDiscreteRep x (map Money.discreteRep . QC.shrink)
-
-instance QC.Arbitrary (Money.Dense currency) where
-  arbitrary = do
-    Just x <- QC.suchThat (Money.dense <$> QC.arbitrary) isJust
-    pure x
-  shrink = catMaybes . fmap Money.dense . QC.shrink . toRational
-
-instance QC.Arbitrary Money.DenseRep where
-  arbitrary = do
-    let md = Money.mkDenseRep <$> QC.arbitrary <*> QC.arbitrary <*> QC.arbitrary
-    Just x <- QC.suchThat md isJust
-    pure x
-  shrink = \x -> Money.withDenseRep x (map Money.denseRep . QC.shrink)
-
-instance QC.Arbitrary (Money.ExchangeRate src dst) where
-  arbitrary = do
-    Just x <- QC.suchThat (fmap Money.exchangeRate QC.arbitrary) isJust
-    pure x
-  shrink =
-    catMaybes . fmap Money.exchangeRate . QC.shrink . Money.fromExchangeRate
-
-instance QC.Arbitrary Money.ExchangeRateRep where
-  arbitrary = do
-    let md = Money.mkExchangeRateRep <$> QC.arbitrary <*> QC.arbitrary
-                                     <*> QC.arbitrary <*> QC.arbitrary
-    Just x <- QC.suchThat md isJust
-    pure x
-  shrink = \x ->
-    Money.withExchangeRateRep x (map Money.exchangeRateRep . QC.shrink)
-
---------------------------------------------------------------------------------
-
-main :: IO ()
-main =  Tasty.defaultMainWithIngredients
-  [ Tasty.consoleTestReporter
-  , Tasty.listingTests
-  ] tests
-
-tests :: Tasty.TestTree
-tests =
-  Tasty.testGroup "root"
-  [ testCurrencies
-  , testCurrencyUnits
-  , testExchange
-  ]
-
-testCurrencies :: Tasty.TestTree
-testCurrencies =
-  Tasty.testGroup "Currency"
-  [ testDense (Proxy :: Proxy "BTC")  -- A cryptocurrency.
-  , testDense (Proxy :: Proxy "USD")  -- A fiat currency with decimal fractions.
-  , testDense (Proxy :: Proxy "VUV")  -- A fiat currency with non-decimal fractions.
-  , testDense (Proxy :: Proxy "XAU")  -- A precious metal.
-  ]
-
-testCurrencyUnits :: Tasty.TestTree
-testCurrencyUnits =
-  Tasty.testGroup "Currency units"
-  [ testDiscrete (Proxy :: Proxy "BTC") (Proxy :: Proxy "BTC")
-  , testDiscrete (Proxy :: Proxy "BTC") (Proxy :: Proxy "satoshi")
-  , testDiscrete (Proxy :: Proxy "BTC") (Proxy :: Proxy "bitcoin")
-  , testDiscrete (Proxy :: Proxy "USD") (Proxy :: Proxy "USD")
-  , testDiscrete (Proxy :: Proxy "USD") (Proxy :: Proxy "cent")
-  , testDiscrete (Proxy :: Proxy "USD") (Proxy :: Proxy "dollar")
-  , testDiscrete (Proxy :: Proxy "VUV") (Proxy :: Proxy "vatu")
-  , testDiscrete (Proxy :: Proxy "XAU") (Proxy :: Proxy "micrograin")
-  , testDiscrete (Proxy :: Proxy "XAU") (Proxy :: Proxy "milligrain")
-  , testDiscrete (Proxy :: Proxy "XAU") (Proxy :: Proxy "grain")
-  ]
-
-testDense
-  :: forall currency
-  .  KnownSymbol currency
-  => Proxy currency
-  -> Tasty.TestTree
-testDense pc =
-  Tasty.testGroup ("Dense " ++ show (symbolVal pc))
-  [ QC.testProperty "read . show == id" $
-      QC.forAll QC.arbitrary $ \(x :: Money.Dense currency) ->
-         x === read (show x)
-  , QC.testProperty "fromDenseRep . denseRep == Just" $
-      QC.forAll QC.arbitrary $ \(x :: Money.Dense currency) ->
-         Just x === Money.fromDenseRep (Money.denseRep x)
-  , QC.testProperty "fromDenseRep works only for same currency" $
-      QC.forAll QC.arbitrary $ \(dr :: Money.DenseRep) ->
-        (Money.denseRepCurrency dr /= symbolVal pc)
-           ==> isNothing (Money.fromDenseRep dr :: Maybe (Money.Dense currency))
-  , QC.testProperty "withDenseRep" $
-      QC.forAll QC.arbitrary $ \(x :: Money.Dense currency) ->
-        let dr = Money.denseRep x
-        in Money.withDenseRep dr $ \x' ->
-             (show x, dr, Money.denseRep (x + 1))
-                === (show x', Money.denseRep x', Money.denseRep (x' + 1))
-
-  , QC.testProperty "Aeson encoding roundtrip" $
-      QC.forAll QC.arbitrary $ \(x :: Money.Dense currency) ->
-         Just x === Ae.decode (Ae.encode x)
-  , QC.testProperty "Aeson encoding roundtrip (DenseRep)" $
-      QC.forAll QC.arbitrary $ \(x :: Money.Dense currency) ->
-         let x' = Money.denseRep x
-         in Just x' === Ae.decode (Ae.encode x')
-  , QC.testProperty "Aeson encoding roundtrip (Dense through DenseRep)" $
-      QC.forAll QC.arbitrary $ \(x :: Money.Dense currency) ->
-         Just x === Ae.decode (Ae.encode (Money.denseRep x))
-  , QC.testProperty "Aeson encoding roundtrip (DenseRep through Dense)" $
-      QC.forAll QC.arbitrary $ \(x :: Money.Dense currency) ->
-         Just (Money.denseRep x) === Ae.decode (Ae.encode x)
-
-  , QC.testProperty "Binary encoding roundtrip" $
-      QC.forAll QC.arbitrary $ \(x :: Money.Dense currency) ->
-         let Right (_,_,y) = Binary.decodeOrFail (Binary.encode x)
-         in x === y
-  , QC.testProperty "Binary encoding roundtrip (DenseRep)" $
-      QC.forAll QC.arbitrary $ \(x :: Money.Dense currency) ->
-         let x' = Money.denseRep x
-             bs = Binary.encode x'
-         in Right (mempty, BSL.length bs, x') === Binary.decodeOrFail bs
-  , QC.testProperty "Binary encoding roundtrip (Dense through DenseRep)" $
-      QC.forAll QC.arbitrary $ \(x :: Money.Dense currency) ->
-         let x' = Money.denseRep x
-             bs = Binary.encode x'
-         in Right (mempty, BSL.length bs, x) === Binary.decodeOrFail bs
-  , QC.testProperty "Binary encoding roundtrip (DenseRep through Dense)" $
-      QC.forAll QC.arbitrary $ \(x :: Money.Dense currency) ->
-         let x' = Money.denseRep x
-             bs = Binary.encode x
-         in Right (mempty, BSL.length bs, x') === Binary.decodeOrFail bs
-
-  , QC.testProperty "Cereal encoding roundtrip" $
-      QC.forAll QC.arbitrary $ \(x :: Money.Dense currency) ->
-         Right x === Cereal.decode (Cereal.encode x)
-  , QC.testProperty "Cereal encoding roundtrip (DenseRep)" $
-      QC.forAll QC.arbitrary $ \(x :: Money.Dense currency) ->
-         let x' = Money.denseRep x
-         in Right x' === Cereal.decode (Cereal.encode x')
-  , QC.testProperty "Cereal encoding roundtrip (Dense through DenseRep)" $
-      QC.forAll QC.arbitrary $ \(x :: Money.Dense currency) ->
-         Right x === Cereal.decode (Cereal.encode (Money.denseRep x))
-  , QC.testProperty "Cereal encoding roundtrip (DenseRep through Dense)" $
-      QC.forAll QC.arbitrary $ \(x :: Money.Dense currency) ->
-         Right (Money.denseRep x) === Cereal.decode (Cereal.encode x)
-
-  , QC.testProperty "Store encoding roundtrip" $
-      QC.forAll QC.arbitrary $ \(x :: Money.Dense currency) ->
-         Right x === Store.decode (Store.encode x)
-  , QC.testProperty "Store encoding roundtrip (DenseRep)" $
-      QC.forAll QC.arbitrary $ \(x :: Money.Dense currency) ->
-         let x' = Money.denseRep x
-         in Right x' === Store.decode (Store.encode x')
-  , QC.testProperty "Store encoding roundtrip (Dense through DenseRep)" $
-      QC.forAll QC.arbitrary $ \(x :: Money.Dense currency) ->
-         Right x === Store.decode (Store.encode (Money.denseRep x))
-  , QC.testProperty "Store encoding roundtrip (DenseRep through Dense)" $
-      QC.forAll QC.arbitrary $ \(x :: Money.Dense currency) ->
-         Right (Money.denseRep x) === Store.decode (Store.encode x)
-  ]
-
-testExchange :: Tasty.TestTree
-testExchange =
-  Tasty.testGroup "Exchange"
-  [ testExchangeRate (Proxy :: Proxy "BTC") (Proxy :: Proxy "BTC")
-  , testExchangeRate (Proxy :: Proxy "BTC") (Proxy :: Proxy "USD")
-  , testExchangeRate (Proxy :: Proxy "BTC") (Proxy :: Proxy "VUV")
-  , testExchangeRate (Proxy :: Proxy "BTC") (Proxy :: Proxy "XAU")
-  , testExchangeRate (Proxy :: Proxy "USD") (Proxy :: Proxy "BTC")
-  , testExchangeRate (Proxy :: Proxy "USD") (Proxy :: Proxy "USD")
-  , testExchangeRate (Proxy :: Proxy "USD") (Proxy :: Proxy "VUV")
-  , testExchangeRate (Proxy :: Proxy "USD") (Proxy :: Proxy "XAU")
-  , testExchangeRate (Proxy :: Proxy "VUV") (Proxy :: Proxy "BTC")
-  , testExchangeRate (Proxy :: Proxy "VUV") (Proxy :: Proxy "USD")
-  , testExchangeRate (Proxy :: Proxy "VUV") (Proxy :: Proxy "VUV")
-  , testExchangeRate (Proxy :: Proxy "VUV") (Proxy :: Proxy "XAU")
-  , testExchangeRate (Proxy :: Proxy "XAU") (Proxy :: Proxy "BTC")
-  , testExchangeRate (Proxy :: Proxy "XAU") (Proxy :: Proxy "USD")
-  , testExchangeRate (Proxy :: Proxy "XAU") (Proxy :: Proxy "VUV")
-  , testExchangeRate (Proxy :: Proxy "XAU") (Proxy :: Proxy "XAU")
-  ]
-
-testDiscrete
-  :: forall (currency :: Symbol) (unit :: Symbol)
-  .  ( Money.GoodScale (Money.Scale currency unit)
-     , KnownSymbol currency
-     , KnownSymbol unit )
-  => Proxy currency
-  -> Proxy unit
-  -> Tasty.TestTree
-testDiscrete pc pu =
-  Tasty.testGroup ("Discrete " ++ show (symbolVal pc) ++ " "
-                               ++ show (symbolVal pu))
-  [ testRounding pc pu
-  , QC.testProperty "read . show == id" $
-      QC.forAll QC.arbitrary $ \(x :: Money.Discrete currency unit) ->
-         x === read (show x)
-  , QC.testProperty "fromDiscreteRep . discreteRep == Just" $
-      QC.forAll QC.arbitrary $ \(x :: Money.Discrete currency unit) ->
-         Just x === Money.fromDiscreteRep (Money.discreteRep x)
-  , QC.testProperty "fromDiscreteRep works only for same currency and scale" $
-      QC.forAll QC.arbitrary $ \(dr :: Money.DiscreteRep) ->
-        ((Money.discreteRepCurrency dr /= symbolVal pc) &&
-         (Money.discreteRepScale dr /=
-             Money.scale (Proxy :: Proxy (Money.Scale currency unit)))
-        ) ==> isNothing (Money.fromDiscreteRep dr
-                          :: Maybe (Money.Discrete currency unit))
-  , QC.testProperty "withDiscreteRep" $
-      QC.forAll QC.arbitrary $ \(x :: Money.Discrete currency unit) ->
-        let dr = Money.discreteRep x
-        in ( Money.withDiscreteRep dr $ \x' ->
-                (show x, dr, Money.discreteRep (x + 1))
-                   === (show x', Money.discreteRep x', Money.discreteRep (x' + 1))
-           ) :: QC.Property
-
-  , QC.testProperty "Aeson encoding roundtrip" $
-      QC.forAll QC.arbitrary $ \(x :: Money.Discrete currency unit) ->
-         Just x === Ae.decode (Ae.encode x)
-  , QC.testProperty "Aeson encoding roundtrip (DiscreteRep)" $
-      QC.forAll QC.arbitrary $ \(x :: Money.Discrete currency unit) ->
-         let x' = Money.discreteRep x
-         in Just x' === Ae.decode (Ae.encode x')
-  , QC.testProperty "Aeson encoding roundtrip (Discrete through DiscreteRep)" $
-      QC.forAll QC.arbitrary $ \(x :: Money.Discrete currency unit) ->
-         Just x === Ae.decode (Ae.encode (Money.discreteRep x))
-  , QC.testProperty "Aeson encoding roundtrip (DiscreteRep through Discrete)" $
-      QC.forAll QC.arbitrary $ \(x :: Money.Discrete currency unit) ->
-         Just (Money.discreteRep x) === Ae.decode (Ae.encode x)
-
-  , QC.testProperty "Binary encoding roundtrip" $
-      QC.forAll QC.arbitrary $ \(x :: Money.Discrete currency unit) ->
-         let Right (_,_,y) = Binary.decodeOrFail (Binary.encode x)
-         in x === y
-  , QC.testProperty "Binary encoding roundtrip (DiscreteRep)" $
-      QC.forAll QC.arbitrary $ \(x :: Money.Discrete currency unit) ->
-         let x' = Money.discreteRep x
-             bs = Binary.encode x'
-         in Right (mempty, BSL.length bs, x') === Binary.decodeOrFail bs
-  , QC.testProperty "Binary encoding roundtrip (Discrete through DiscreteRep)" $
-      QC.forAll QC.arbitrary $ \(x :: Money.Discrete currency unit) ->
-         let x' = Money.discreteRep x
-             bs = Binary.encode x'
-         in Right (mempty, BSL.length bs, x) === Binary.decodeOrFail bs
-  , QC.testProperty "Binary encoding roundtrip (DiscreteRep through Discrete)" $
-      QC.forAll QC.arbitrary $ \(x :: Money.Discrete currency unit) ->
-         let x' = Money.discreteRep x
-             bs = Binary.encode x
-         in Right (mempty, BSL.length bs, x') === Binary.decodeOrFail bs
-
-  , QC.testProperty "Cereal encoding roundtrip" $
-      QC.forAll QC.arbitrary $ \(x :: Money.Discrete currency unit) ->
-         Right x === Cereal.decode (Cereal.encode x)
-  , QC.testProperty "Cereal encoding roundtrip (DiscreteRep)" $
-      QC.forAll QC.arbitrary $ \(x :: Money.Discrete currency unit) ->
-         let x' = Money.discreteRep x
-         in Right x' === Cereal.decode (Cereal.encode x')
-  , QC.testProperty "Cereal encoding roundtrip (Discrete through DiscreteRep)" $
-      QC.forAll QC.arbitrary $ \(x :: Money.Discrete currency unit) ->
-         Right x === Cereal.decode (Cereal.encode (Money.discreteRep x))
-  , QC.testProperty "Cereal encoding roundtrip (DiscreteRep through Discrete)" $
-      QC.forAll QC.arbitrary $ \(x :: Money.Discrete currency unit) ->
-         Right (Money.discreteRep x) === Cereal.decode (Cereal.encode x)
-
-  , QC.testProperty "Store encoding roundtrip" $
-      QC.forAll QC.arbitrary $ \(x :: Money.Discrete currency unit) ->
-         Right x === Store.decode (Store.encode x)
-  , QC.testProperty "Store encoding roundtrip (DiscreteRep)" $
-      QC.forAll QC.arbitrary $ \(x :: Money.Discrete currency unit) ->
-         let x' = Money.discreteRep x
-         in Right x' === Store.decode (Store.encode x')
-  , QC.testProperty "Store encoding roundtrip (Discrete through DiscreteRep)" $
-      QC.forAll QC.arbitrary $ \(x :: Money.Discrete currency unit) ->
-         Right x === Store.decode (Store.encode (Money.discreteRep x))
-  , QC.testProperty "Store encoding roundtrip (DiscreteRep through Discrete)" $
-      QC.forAll QC.arbitrary $ \(x :: Money.Discrete currency unit) ->
-         Right (Money.discreteRep x) === Store.decode (Store.encode x)
-  ]
-
-testExchangeRate
-  :: forall (src :: Symbol) (dst :: Symbol)
-  .  (KnownSymbol src, KnownSymbol dst)
-  => Proxy src
-  -> Proxy dst
-  -> Tasty.TestTree
-testExchangeRate ps pd =
-  Tasty.testGroup ("ExchangeRate " ++ show (symbolVal ps) ++ " "
-                                   ++ show (symbolVal pd))
-  [ QC.testProperty "read . show == id" $
-      QC.forAll QC.arbitrary $ \(xr :: Money.ExchangeRate src dst) ->
-         xr === read (show xr)
-  , QC.testProperty "flipExchangeRate . flipExchangeRate == id" $
-      QC.forAll QC.arbitrary $ \(xr :: Money.ExchangeRate src dst) ->
-         let xr' = Money.flipExchangeRate xr
-         in (Money.fromExchangeRate xr /= Money.fromExchangeRate xr')
-               ==> (xr === Money.flipExchangeRate xr')
-  , QC.testProperty "exchange (flipExchangeRate x) . exchange x == id" $
-      QC.forAll QC.arbitrary $
-         \( c0 :: Money.Dense src
-          , xr :: Money.ExchangeRate src dst
-          ) -> c0 === Money.exchange (Money.flipExchangeRate xr)
-                                     (Money.exchange xr c0)
-  , QC.testProperty "x == 1 ===> exchange x == id" $
-      QC.forAll QC.arbitrary $
-         \( c0 :: Money.Dense src
-          ) -> let Just xr = Money.exchangeRate 1
-               in toRational c0 === toRational (Money.exchange xr c0)
-  , QC.testProperty "x /= 1 ===> exchange x /= id" $
-      QC.forAll QC.arbitrary $
-         \( c0 :: Money.Dense src
-          , xr :: Money.ExchangeRate src dst
-          ) -> (Money.fromExchangeRate xr /= 1)
-                  ==> (toRational c0 /= toRational (Money.exchange xr c0))
-  , QC.testProperty "fromExchangeRateRep . exchangeRateRep == Just" $
-      QC.forAll QC.arbitrary $ \(x :: Money.ExchangeRate src dst) ->
-         Just x === Money.fromExchangeRateRep (Money.exchangeRateRep x)
-  , QC.testProperty "fromExchangeRateRep works only for same currencies" $
-      QC.forAll QC.arbitrary $ \(x :: Money.ExchangeRateRep) ->
-        ((Money.exchangeRateRepSrcCurrency x /= symbolVal ps) &&
-         (Money.exchangeRateRepDstCurrency x /= symbolVal pd))
-            ==> isNothing (Money.fromExchangeRateRep x
-                            :: Maybe (Money.ExchangeRate src dst))
-  , QC.testProperty "withExchangeRateRep" $
-      QC.forAll QC.arbitrary $ \(x :: Money.ExchangeRate src dst) ->
-        let dr = Money.exchangeRateRep x
-        in Money.withExchangeRateRep dr $ \x' ->
-             (show x, dr) === (show x', Money.exchangeRateRep x')
-
-  , QC.testProperty "Aeson encoding roundtrip" $
-      QC.forAll QC.arbitrary $ \(x :: Money.ExchangeRate src dst) ->
-         Just x === Ae.decode (Ae.encode x)
-  , QC.testProperty "Aeson encoding roundtrip (ExchangeRateRep)" $
-      QC.forAll QC.arbitrary $ \(x :: Money.ExchangeRate src dst) ->
-         let x' = Money.exchangeRateRep x
-         in Just x' === Ae.decode (Ae.encode x')
-  , QC.testProperty "Aeson encoding roundtrip (ExchangeRate through ExchangeRateRep)" $
-      QC.forAll QC.arbitrary $ \(x :: Money.ExchangeRate src dst) ->
-         Just x === Ae.decode (Ae.encode (Money.exchangeRateRep x))
-  , QC.testProperty "Aeson encoding roundtrip (ExchangeRateRep through ExchangeRate)" $
-      QC.forAll QC.arbitrary $ \(x :: Money.ExchangeRate src dst) ->
-         Just (Money.exchangeRateRep x) === Ae.decode (Ae.encode x)
-
-  , QC.testProperty "Binary encoding roundtrip" $
-      QC.forAll QC.arbitrary $ \(x :: Money.ExchangeRate src dst) ->
-         let Right (_,_,y) = Binary.decodeOrFail (Binary.encode x)
-         in x === y
-  , QC.testProperty "Binary encoding roundtrip (ExchangeRateRep)" $
-      QC.forAll QC.arbitrary $ \(x :: Money.ExchangeRate src dst) ->
-         let x' = Money.exchangeRateRep x
-             bs = Binary.encode x'
-         in Right (mempty, BSL.length bs, x') === Binary.decodeOrFail bs
-  , QC.testProperty "Binary encoding roundtrip (ExchangeRate through ExchangeRateRep)" $
-      QC.forAll QC.arbitrary $ \(x :: Money.ExchangeRate src dst) ->
-         let x' = Money.exchangeRateRep x
-             bs = Binary.encode x'
-         in Right (mempty, BSL.length bs, x) === Binary.decodeOrFail bs
-  , QC.testProperty "Binary encoding roundtrip (ExchangeRateRep through ExchangeRate)" $
-      QC.forAll QC.arbitrary $ \(x :: Money.ExchangeRate src dst) ->
-         let x' = Money.exchangeRateRep x
-             bs = Binary.encode x
-         in Right (mempty, BSL.length bs, x') === Binary.decodeOrFail bs
-
-  , QC.testProperty "Cereal encoding roundtrip" $
-      QC.forAll QC.arbitrary $ \(x :: Money.ExchangeRate src dst) ->
-         Right x === Cereal.decode (Cereal.encode x)
-  , QC.testProperty "Cereal encoding roundtrip (ExchangeRateRep)" $
-      QC.forAll QC.arbitrary $ \(x :: Money.ExchangeRate src dst) ->
-         let x' = Money.exchangeRateRep x
-         in Right x' === Cereal.decode (Cereal.encode x')
-  , QC.testProperty "Cereal encoding roundtrip (ExchangeRate through ExchangeRateRep)" $
-      QC.forAll QC.arbitrary $ \(x :: Money.ExchangeRate src dst) ->
-         Right x === Cereal.decode (Cereal.encode (Money.exchangeRateRep x))
-  , QC.testProperty "Cereal encoding roundtrip (ExchangeRateRep through ExchangeRate)" $
-      QC.forAll QC.arbitrary $ \(x :: Money.ExchangeRate src dst) ->
-         Right (Money.exchangeRateRep x) === Cereal.decode (Cereal.encode x)
-
-  , QC.testProperty "Store encoding roundtrip" $
-      QC.forAll QC.arbitrary $ \(x :: Money.ExchangeRate src dst) ->
-         Right x === Store.decode (Store.encode x)
-  , QC.testProperty "Store encoding roundtrip (ExchangeRateRep)" $
-      QC.forAll QC.arbitrary $ \(x :: Money.ExchangeRate src dst) ->
-         let x' = Money.exchangeRateRep x
-         in Right x' === Store.decode (Store.encode x')
-  , QC.testProperty "Store encoding roundtrip (ExchangeRate through ExchangeRateRep)" $
-      QC.forAll QC.arbitrary $ \(x :: Money.ExchangeRate src dst) ->
-         Right x === Store.decode (Store.encode (Money.exchangeRateRep x))
-  , QC.testProperty "Store encoding roundtrip (ExchangeRateRep through ExchangeRate)" $
-      QC.forAll QC.arbitrary $ \(x :: Money.ExchangeRate src dst) ->
-         Right (Money.exchangeRateRep x) === Store.decode (Store.encode x)
-  ]
-
-testRounding
-  :: forall (currency :: Symbol) (unit :: Symbol)
-  .  (Money.GoodScale (Money.Scale currency unit), KnownSymbol currency)
-  => Proxy currency
-  -> Proxy unit
-  -> Tasty.TestTree
-testRounding _ _ =
-    Tasty.testGroup "Rounding"
-    [ QC.testProperty "floor"    $ QC.forAll QC.arbitrary (g Money.floor)
-    , QC.testProperty "ceiling"  $ QC.forAll QC.arbitrary (g Money.ceiling)
-    , QC.testProperty "round"    $ QC.forAll QC.arbitrary (g Money.round)
-    , QC.testProperty "truncate" $ QC.forAll QC.arbitrary (g Money.truncate)
-    ]
-  where
-    g f = \(x :: Money.Dense currency) -> x === case f x of
-      (y, Nothing) -> Money.fromDiscrete (y :: Money.Discrete currency unit)
-      (y, Just z)  -> Money.fromDiscrete y + z