diff --git a/CHANGELOG.md b/CHANGELOG.md new file mode 100644 --- /dev/null +++ b/CHANGELOG.md @@ -0,0 +1,1 @@ +# 0.1.0 diff --git a/LICENSE.md b/LICENSE.md new file mode 100644 --- /dev/null +++ b/LICENSE.md @@ -0,0 +1,22 @@ +MIT License + +Copyright (c) 2016 Juan Pedro Villa Isaza + +Permission is hereby granted, free of charge, to any person obtaining +a copy of this software and associated documentation files (the +"Software"), to deal in the Software without restriction, including +without limitation the rights to use, copy, modify, merge, publish, +distribute, sublicense, and/or sell copies of the Software, and to +permit persons to whom the Software is furnished to do so, subject to +the following conditions: + +The above copyright notice and this permission notice shall be +included in all copies or substantial portions of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, +EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF +MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. +IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY +CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, +TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE +SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. diff --git a/README.md b/README.md new file mode 100644 --- /dev/null +++ b/README.md @@ -0,0 +1,6 @@ +# money + +[![][1]][0] + +[0]: https://circleci.com/gh/jpvillaisaza/money +[1]: https://circleci.com/gh/jpvillaisaza/money.svg?style=svg diff --git a/Setup.hs b/Setup.hs new file mode 100644 --- /dev/null +++ b/Setup.hs diff --git a/money.cabal b/money.cabal new file mode 100644 --- /dev/null +++ b/money.cabal @@ -0,0 +1,63 @@ +name: money +version: 0.1.0 + +build-type: Simple +cabal-version: >= 1.10 + +license: MIT +license-file: LICENSE.md + +copyright: 2016 Juan Pedro Villa Isaza +author: Juan Pedro Villa Isaza +maintainer: Juan Pedro Villa Isaza + +stability: Experimental + +homepage: https://github.com/jpvillaisaza/money +bug-reports: https://github.com/jpvillaisaza/money/issues + +synopsis: Money +description: Money. + +category: Finance + +tested-with: GHC == 8.0.1 + +extra-source-files: + CHANGELOG.md + README.md + + +library + hs-source-dirs: + src + exposed-modules: + Data.Money + Data.Money.Currency + build-depends: + base >= 4.9 && < 4.10 + default-language: + Haskell2010 + ghc-options: + -Wall + + +test-suite examples + type: + exitcode-stdio-1.0 + hs-source-dirs: + test/examples + main-is: + Main.hs + build-depends: + base + , doctest >= 0.11 && < 0.12 + default-language: + Haskell2010 + ghc-options: + -Wall -threaded -rtsopts -with-rtsopts=-N + + +source-repository head + type: git + location: https://github.com/jpvillaisaza/money diff --git a/src/Data/Money.hs b/src/Data/Money.hs new file mode 100644 --- /dev/null +++ b/src/Data/Money.hs @@ -0,0 +1,220 @@ +{-# LANGUAGE FlexibleContexts #-} +{-# LANGUAGE FlexibleInstances #-} +{-# LANGUAGE GeneralizedNewtypeDeriving #-} +{-# LANGUAGE RecordWildCards #-} + +---------------------------------------------------------------------- +-- | +-- Module: Data.Money +-- +-- +-- +---------------------------------------------------------------------- + +module Data.Money + ( -- * Currencies + module Data.Money.Currency + -- * Money + , Money (..) + -- * Exchange rates + , ExchangeRate (..) + -- * Interchanges + , interchange + -- * Conversions + , convert + , convert' + ) + where + +-- money +import Data.Money.Currency + + +---------------------------------------------------------------------- +-- * Money +---------------------------------------------------------------------- + +-- | +-- +-- Money in a currency. +-- +-- Examples: +-- +-- >>> 1000 :: Money COP +-- COP 1000.0 +-- +-- >>> 1000 :: Money EUR +-- EUR 1000.0 +-- +-- >>> 1000 :: Money USD +-- USD 1000.0 +-- +-- >>> 999.99 :: Money USD +-- USD 999.99 +-- +-- >>> 1000 + 500 :: Money COP +-- COP 1500.0 +-- +-- >>> (1000 :: Money COP) + (500 :: Money EUR) +-- ... +-- +-- >>> 1000 == (500 * 2 :: Money USD) +-- True +-- +-- >>> 1000 < (500 :: Money EUR) +-- False + +newtype Money currency = + Money + { getAmount :: Rational + } + deriving (Eq, Fractional, Num, Ord) + + +-- | +-- +-- Show money in COP. + +instance Show (Money COP) where + show Money {..} = + "COP " ++ show (fromRational getAmount :: Double) + + +-- | +-- +-- Show money in EUR. + +instance Show (Money EUR) where + show Money {..} = + "EUR " ++ show (fromRational getAmount :: Double) + + +-- | +-- +-- Show money in USD. + +instance Show (Money USD) where + show Money {..} = + "USD " ++ show (fromRational getAmount :: Double) + + +---------------------------------------------------------------------- +-- * Exchange rates +---------------------------------------------------------------------- + +-- | +-- +-- An exchange rate, that is, the value of one currency for the +-- purpose of conversion to another. +-- +-- Examples: +-- +-- >>> 3167.20 :: ExchangeRate USD COP +-- COP 3167.2 +-- +-- >>> 1.06 :: ExchangeRate EUR USD +-- USD 1.06 +-- +-- >>> 0.94 :: ExchangeRate USD EUR +-- EUR 0.94 + +newtype ExchangeRate currency1 currency2 = + ExchangeRate + { getExchangeRate :: Money currency2 + } + deriving (Eq, Fractional, Num) + + +-- | +-- +-- + +instance Show (Money cur2) => Show (ExchangeRate cur1 cur2) where + show = + show . getExchangeRate + + +---------------------------------------------------------------------- +-- * Interchanges +---------------------------------------------------------------------- + +-- | +-- +-- Interchange (or flip) an exchange rate. +-- +-- Examples: +-- +-- >>> interchange (1.06 :: ExchangeRate EUR USD) +-- EUR 0.94... +-- +-- >>> interchange (0.94 :: ExchangeRate USD EUR) +-- USD 1.06... +-- +-- >>> interchange (interchange (1.06 :: ExchangeRate EUR USD)) +-- USD 1.06 +-- +-- >>> interchange (interchange (0.94 :: ExchangeRate USD EUR)) +-- EUR 0.94 + +interchange + :: ExchangeRate cur1 cur2 + -> ExchangeRate cur2 cur1 +interchange (ExchangeRate exchangeRate) = + ExchangeRate (Money (1 / getAmount exchangeRate)) + + +---------------------------------------------------------------------- +-- * Conversions +---------------------------------------------------------------------- + +-- | +-- +-- Convert money using an exchange rate. +-- +-- Examples: +-- +-- >>> usdToCop = 3182.01 :: ExchangeRate USD COP +-- +-- >>> convert usdToCop 1000 +-- COP 3182010.0 +-- +-- >>> convert (interchange usdToCop) 1000 +-- USD 0.31... +-- +-- >>> convert (interchange usdToCop) (convert usdToCop 1000) +-- USD 1000.0 + +convert + :: ExchangeRate cur1 cur2 + -> Money cur1 + -> Money cur2 +convert (ExchangeRate exchangeRate) (Money amount) = + Money (amount * getAmount exchangeRate) + + +-- | +-- +-- Convert money using an interchanged (or flipped) exchange rate. +-- +-- Examples: +-- +-- >>> usdToCop = 3182.01 :: ExchangeRate USD COP +-- +-- >>> convert' usdToCop 1000 +-- USD 0.31... +-- +-- >>> convert' (interchange usdToCop) 1000 +-- COP 3182010.0 +-- +-- >>> convert' usdToCop (convert' (interchange usdToCop) 1000) +-- USD 1000.0 +-- +-- >>> convert' usdToCop (convert usdToCop 1000) +-- USD 1000.0 + +convert' + :: ExchangeRate cur2 cur1 + -> Money cur1 + -> Money cur2 +convert' exchangeRate = + convert (interchange exchangeRate) diff --git a/src/Data/Money/Currency.hs b/src/Data/Money/Currency.hs new file mode 100644 --- /dev/null +++ b/src/Data/Money/Currency.hs @@ -0,0 +1,39 @@ +---------------------------------------------------------------------- +-- | +-- Module: Data.Money.Currency +-- +-- +-- +---------------------------------------------------------------------- + +module Data.Money.Currency + ( COP + , EUR + , USD + ) + where + + +---------------------------------------------------------------------- +-- * Currencies +---------------------------------------------------------------------- + +-- | +-- +-- The Colombian peso. + +data COP + + +-- | +-- +-- The euro. + +data EUR + + +-- | +-- +-- The United States dollar. + +data USD diff --git a/test/examples/Main.hs b/test/examples/Main.hs new file mode 100644 --- /dev/null +++ b/test/examples/Main.hs @@ -0,0 +1,19 @@ +module Main + ( main + ) + where + +-- doctest +import Test.DocTest (doctest) + + +-- | +-- +-- + +main :: IO () +main = + doctest + [ "-isrc" + , "src/Data/Money.hs" + ]