packages feed

exinst 0.2 → 0.9

raw patch · 15 files changed

Files

CHANGELOG.md view
@@ -1,10 +1,130 @@+# Version 0.9++* BACKWARDS COMPATIBLE COMPILER ASSISTED CHANGE: The `Show`, `Read`,+  `Eq`, `Ord` and `Generic` instances now live in the `exinst-base` package.+  This is so that `exinst` doesn't need to depend on the large+  `singletons-base`. Users wanting access to those instances need to import+  `Exinst.Base` explicitly.++* Builds with GHC 9.4.++* The tests for `exinst` now live in `exinst-base`.++# Version 0.8++* Builds with GHC 8.10 and `singletons-2.7`.++# Version 0.7++* BACKWARDS COMPATIBLE COMPILER ASSISTED CHANGE: All of the cabal flags+  for turning on and off instances were removed.  The `hashable` are now+  always exported from the `exinst`, and the `aeson`, `bytes`,+  `cereal` and `serialise` instances  are now exported from new+  packages `exinst-aeson`, `exinst-bytes`, `exinst-cereal` and+  `exinst-serialise`. The instances exported from those packages are+  the same as the ones exported with `exinst-0.6`.+++# Version 0.6++* The `binary` and `deepseq` Cabal flags were removed since these two packages+  are always included with the GHC distribution, so it doesn't make sense to+  make them optional.++* The optional dependencies hidden behind Cabal flags now apply to the test+  suite as well.++* Builds with GHC 8.4.+++# Version 0.5++* BREAKING: Depend on `singletons == 2.3.*`.++* Add `same{1,2,3,4}`.++* Add dependencies on `cborg` and `serialise`++* Add instances for `serialise` (binary CBOR encoding/decoding)+++# Version 0.4++* BREAKING: Decouple `binary` and `cereal` instances from `bytes`. This+  introduces a slight backwards incompatible change if you were using some+  `Serial` instances that depended on host endianness (such as `Int`).++* Add `P1`, `P2`, `P3`, `P4`.++* Add `S1`, `S2`, `S3`, `S4`.++* Add `Read` instances for `Some{1,2,3,4}`.++* Moved documentation from `README.md` into the top-level `Exinst` module.+++# Version 0.3.0.1++* Removed dependency on `generic-random`.++* Correctly deal with cabal flags for `deepseq` and `hashable`.++* Add `binary`'s `Data.Binary.Binary` and `cereal`'s `Data.Serialize.Serialize`+  instances for `Some{1,2,3,4}`. These instances are compatible with each other+  and rely on the `Data.Bytes.Serial` instances.+++# Version 0.3++* BREAKING: Renamed module `Exinst.Singletons` to  `Exinst`.++* BREAKING: The `Exinst.Instances.Base` module is gone. The `base` instances are+  now exported from `Exinst`.++* Add `Dict0`.++* Re-export `Constraint` from `base`.++* Add `Dict{0,2,3,4}` instances for `Bool`.++* Add `GHC.Generics.Generic` support for `Some{1,2,3,4}`. This only works for+  indexes with `PEnum` and `PBounded` instances.++* Added tests.++* Added `Test.QuickCheck.Arbitrary` instances for `Some{1,2,3,4}` in+  `Exinst.Instances.QuickCheck`. These instances and their dependency on+  `QuickCheck` can be toggled with the `quickcheck` Cabal flag.++* Added `Data.Aeson.{FromJSON,ToJSON}` instances for `Some{1,2,3,4}` in+  `Exinst.Instances.Aeson`. These instances and their dependency on+  `aeson` can be toggled with the `aeson` Cabal flag. These instances used to+  exist in now-deprecated the `exinst-aeson` package, and are compatible with+  them.++* Added `Bytes.Serial.Serial` instances for `Some{1,2,3,4}` in+  `Exinst.Instances.Bytes`. These instances and their dependency on `bytes` can+  be toggled with the `bytes` Cabal flag. These instances used to exist in+  now-deprecated the `exinst-bytes` package, and are compatible with them.++* Added `Control.DeepSeq.NFData` instances for `Some{1,2,3,4}` in+  `Exinst.Instances.DeepSeq`. These instances and their dependency on `deepseq`+  can be toggled with the `deepseq` Cabal flag. These instances used to exist in+  now-deprecated the `exinst-deepseq` package, and are compatible with them.++* Added `Data.Hashable.Hashable` instances for `Some{1,2,3,4}` in+  `Exinst.Instances.DeepSeq`. These instances and their dependency on `hashable`+  can be toggled with the `hashable` Cabal flag. These instances used to exist+  in now-deprecated the `exinst-hashable` package, and are compatible with them.++ # Version 0.2  * Depend on `singletons-2.2`, which means `KProxy` is gone.  * Add `_Some{1,2,3,4}` prisms. -* Add `Dict` instance for `Bool`.+* Add `Dict1` instance for `Bool`.  * Add `some{1,2,3,4}SingRep`.
LICENSE.txt view
@@ -1,4 +1,4 @@-Copyright (c) 2015-2016, Renzo Carbonara+Copyright (c) 2015-2018, Renzo Carbonara  All rights reserved.
README.md view
@@ -1,565 +1,9 @@ # exinst -> See the [BSD3 LICENSE](https://github.com/k0001/exinst/blob/master/exinst/LICENSE.txt)-> file to learn about the legal terms and conditions for this library.--Exinst is a library providing you with tools to automatically derive instances for-type-indexed types whose type-indexes have been existentialized. Currently it only-supports using [`singleton`](https://hackage.haskell.org/package/singletons) types as-type-indexes.--> TODO: Support for non-singleton-types types with kind `*` using `Typeable` should-> be possible, but I haven't worked on that yet. It's on the roadmap.--In short, what `exinst` currently gives you is: For any type ``t :: k -> *``,-if `k` is a singleton type and `c (t k) :: Constraint` is satisfied, then you can-existentialize away the `k` parameter with `Some1 t`, and have `c (Some1 t)`-automatically satisfied. Currently, up to 4 type indexes can be existentialized-using `Some1`, `Some2`, `Some3` and `Some4` respectively.--> NOTE: This tutorial asumes some familiarity with singleton types as implemented-> by the [`singleton`](https://hackage.haskell.org/package/singletons) library.-> A singleton type is, in very rough terms, a type inhabited by a single term,-> which allows one to go from its term-level representation to its type-level-> representation and back without much trouble. A bit like the term `()`, which-> is of type `()`: whenever you have the type `()` you know what that its-> term-level representation must be `()`, and whenever you have the term `()`-> you know that its type must be `()`.--## Motivation--As a motivation, let's consider the following example:--```haskell-{-# LANGUAGE GADTs #-}-{-# LANGUAGE DataKinds #-}-{-# LANGUAGE KindSignatures #-}-{-# LANGUAGE FlexibleInstances #-}-{-# LANGUAGE StandaloneDeriving #-}--data Size = Big | Small--data Receptacle (a :: Size) :: * where-  Vase :: Receptacle 'Small-  Glass :: Receptacle 'Small-  Barrel :: Receptacle 'Big--deriving instance Show (Receptacle a)-```--`Receptacle` can describe three types of receptacles (`Vase`, `Glass` and-`Barrel`), while at the same time being able to indicate, at the type level,-whether the size of the receptacle is `Big` or `Small`. Additionally, we've-provided `Show` instances for `Receptacle`. --Now, if we want to put `Receptacle`s in a container, for example in `[]`, we can-do so only as long as the `Receptacle` type is fully applied and monomorphic. That is, we can-have `[Receptacle 'Small]` and `[Receptacle 'Big]`, but we can't have-`[Receptacle]` nor `[forall a. Receptacle a]`. So, if we want to have `Receptacle`s of different sizes in a-container like `[]`, we need a different solution.--At this point we need to ask ourselves why we need to put `Receptacle`s of-different sizes in a same container. If the answer is something like “because we-want to show all of them, no matter what size they are”, then we should realize-that what we are actually asking for is that no matter what `Size` our-`Receptable` has, we need to be able to find a `Show` instance for that-`Receptacle`. In Haskell, we can express just that using existential types-and constraints hidden behind a data constructor.--```haskell---We need to add these language extensions to the ones in the previous example---{-# LANGUAGE ExistentialQuantification #-}---{-# LANGUAGE FlexibleContexts #-}--data ReceptacleOfAnySizeThatCanBeShown-  = forall a. (Show (Receptacle a))-      => MkReceptacleOfAnySizeThatCanBeShown (Receptacle a)-```--We can construct values of type `ReceptacleOfAnySizeThatCanBeShown` only as long-as there exist a `Show` instance for the `Receptacle a` we give to the-`MkReceptacleOfAnySizeThatCanBeShown` constructor. In our case, both `Receptacle-'Small` and `Receptacle 'Big` have `Show` instances, so all of `Vase`, `Glass` and-`Barrel` can be used successfully with `MkReceptacleOfAnySizeThatCanBeShown`.--Now, `ReceptacleOfAnySizeThatCanBeShown` on itself doesn't yet have a `Show`-instance, and we can't derive one automatically using the `deriving` mechanism,-but we can give an explicit `Show` instance that just forwards the work to the-`Show` instance of the underlying `Receptacle a`.--```haskell-instance Show ReceptacleOfAnySizeThatCanBeShown where-  show (MkReceptacleOfAnySizeThatCanBeShown a) = show a-```--That works as intended:--```-> show (MkReceptacleOfAnySizeThatCanBeShown Vase)-"Vase"-> show (MkReceptacleOfAnySizeThatCanBeShown Barrel)-"Barrel"-```--And now, as we wanted, we can put `Receptacle`s of different sizes in a `[]` and-show them (as long as we wrap each of them as-`ReceptacleOfAnySizeThatCanBeShown`, that is).--```-> map show [MkReceptacleOfAnySizeThatCanBeShown Vase, MkReceptacleOfAnySizeThatCanBeShown Barrel]-["Vase", "Barrel"]-```--However, the above solution is unsatisfying for various reasons: For one, the-`Show` instance for `ReceptacleOfAnySizeThatCanBeShown` works only as long as-the `ReceptacleOfAnySizeThatCanBeShown` itself carries a witness that the `Show`-constraint for `Receptacle a` is satisfied, which means that if we want to write-yet another instance for `ReceptacleOfAnySizeThatCanBeShown` that simply forwards-its implementation to the underlying `Receptacle a`, say `Eq`, then the-`MkReceptacleOfAnySizeThatCanBeShown` constructor would need to be modified to witness-the `Eq (Receptacle a)` instance too:--```haskell-data ReceptacleOfAnySizeThatCanBeShown-  = forall a. (Show (Receptacle a), Eq (Receptacle a))-      => MkReceptacleOfAnySizeThatCanBeShown (Receptacle a)-```--With that in place we can provide an `Eq` instance for-`ReceptacleOfAnySizeThatCanBeShown` as we did for `Show` before, but if we pay-close attention, we can see how the implementation of-`ReceptacleOfAnySizeThatCanBeShown` starts to become a bottleneck: Every-instance we want to provide for `ReceptacleOfAnySizeThatCanBeShown` that simply-forwards its work to the underlying `Receptacle a` needs to be witnessed by-`MkReceptacleOfAnySizeThatCanBeShown` itself, it is not enough that there exists-an instance for `Receptacle a`. Moreover, even the name-`ReceptacleOfAnySizeThatCanBeShown` that we chose before isn't completely-accurate anymore, and will become less and less accurate as we continue adding-constraints to `MkReceptacleOfAnySizeThatCanBeShown`.--Additionally, everywhere we use the `MkReceptacleOfAnySizeThatCanBeShown`-constructor we need to witness that the existentialized `Receptacle a` satisfies-all the required constraints, which means that, if the `Receptacle a` we pass to-`MkReceptacleOfAnySizeThatCanBeShown` is being received, say, as a parameter to-a function, then the type of that function will also require that its caller-satisfies all of the same constraints, even though it is obvious to us,-statically, that the instances exist. We can now see how all of this becomes-unmanegeable, or at least very *boilerplatey*, as those constraints start to-propagate through our code base.--What we need is a way for instances such as the `Show` instance for-`ReceptacleOfAnySizeThatCanBeShown` to find the `Show` instance for `Receptacle-a` without it being explicitely witnessed by the-`MkReceptacleOfAnySizeThatCanBeShown` constructor. That is exactly the problem-that `exinst` solves: allowing *exi*stentials to find their *inst*ances.---## Usage--Given the code for `Size`, `Receptacle` and its `Show` instances above, we can-achieve the same functionality as our initial `ReceptacleOfAnySizeThatCanBeShown` by-existentializing the type indexes of `Receptacle 'Small` and `Receptacle 'Big`-as `Some1 Receptacle`. In order to do that, we must first ensure that `Size` and its-constructors can be used as singleton types (as supported by the `singletons` library),-for which we can use some TH provided by `Data.Singletons.TH`:--```haskell-import Data.Singletons.TH--Data.Singletons.TH.genSingletons [''Size]-```--And we'll also need a `Show` instance for `Size` for reasons that will become-apparent later:--```haskell-deriving instance Show Size-```--Now we can construct a `Show1 Size` and `show` achieving the same results as we-did with `ReceptacleOfAnySizeThatCanBeShown` before.--Note: this code won't work yet. Keep reading.--```-> import Exinst.Singletons (some1)-> import Exinst.Instances.Base ()-> :t some1 Glass-:t some1 Glass :: Some1 Receptacle-> show (some1 Glass)-"Some1 Small Glass"-```--Well, actually, the default `Show` instance for `Some1` shows a bit more of-information, as it permits this string to be `Read` back into a `Some1-Receptacle` if needed, but displaying just `"Glass"` would be possible too, if-desired.--> TODO: Implement said `Read` instance.--The important thing to notice in the example above is that `some1` does not-require us to satisfy a `Show (Receptacle 'Small)` constraint, it just requires-that the type index for the type-indexed type we give it as argument is a-singleton type:--```haskell-some1 :: forall (f1 :: k1 -> *) (a1 :: k1). SingI a1 => f1 a1 -> Some1 f1-```--It is the application of `show` to `some1 Glass` which will fail to compile if-there isn't a `Show` instance for `Receptacle 'Small`, complaining that a `Show`-instance for `Some1 Receptable` can't be found. The reason for this is that even-if `Show` instances for `Some1` are derived for free, they are only derived for-`Some1 (t :: k1 -> *)` where a `Show (t a)` for a specific but statically-unknown `a` can be found at runtime (mostly, there are other minor requirements too).-The mechanism through which instances are found at runtime relies on `Dict` from the-[`constraints`](https://hackage.haskell.org/package/constraints) library, which-`exinst` wraps in a `Dict1` typeclass to be instantiated once per singleton-type.--```haskell--- The Exinst.Singletons.Dict1 class-class Dict1 (c :: * -> Constraint) (f1 :: k1 -> *) where-  dict1 :: Sing (a1 :: k1) -> Dict (c (f1 a1))-```--What `Dict1` says is that: for a type-indexed type `f1`, given a term-level-representation of the singleton type that indexes said `f1`, we can obtain a-witness that the constraint `c` is satisfied by `f1` applied to the singleton-type.--That class seems to be a bit too abstract, but the instances we as users need to-write for it are quite silly and straightforward. Even *boilerplatey* if you-will; they could even be generated using TH--> TODO: Write the TH for deriving the `Dict{1,2,3,4}` implementation.--Here's an example of how to provide `Show` support for `Some1 Receptacle` via-`Dict1`:--```-instance (Show (Receptacle 'Small), Show (Receptacle 'Big)) => Dict1 Show Receptacle where-  dict1 = \x -> case x of-    SSmall -> Dict-    SBig -> Dict-```--The implementation of `dict1` looks quite silly, but it has to look like that as-it is only by pattern-matching on each of the `Sing Size` constructors that we-learn about the type level representation of a singleton type, which we then use-to select the proper `Show` instance among all of those listed in the instance head.--Given this `Dict1` instance, we can proceed to excecute the REPL example mentioned before-and it will work just fine.--However, that `Dict1` instance is still a bit insatisfactory: If we wanted,-again, to provide `Eq` support for our `Some1 Receptacle` type, we would need to-write yet another `Dict1` instance like the one above, but mentioning `Eq`-instead of `Show`. We can do better.--The trick, when writing `Dict1` instances such as the one above, is to leave `c`-and `f1 :: k1 -> *` completely polymorphic, and instead only talk concretely-about the singleton type with kind `k1`. This might sound strange at first, as-`c` and `f1` are the only two type parameters to `Dict1`. But as it often happens-when working with singleton types, we are not particularly interested in the-types involved, but in their kinds instead. So, this is the `Dict1` instance-you often want to write:--```haskell-instance (c (f1 'Small), c (f1 'Big)) => Dict1 c f1 where-  dict1 = \x -> case x of-    SSmall -> Dict-    SBig -> Dict-```--That instance says that for any choice of `c` and `f1 :: Size -> *`, if an-instance for `c (f1 a)` exists for a specific choice of `a`, then, given a term-level representation for that `a` and the aid of `dict1`, said instance can be-looked up at runtime.--Notice that `Some1` itself doesn't have any requirements about `Dict1`, it's the-various instances for `Some1` who rely on `Dict1`. `Dict1` has nothing to do-with `Some1`, nor with the choice of `f` nor with the choice of `c`; it is only-related to the singleton type used as a type-index for `f`.--As of this writing, we can find some ready-made instances for `Some1`, `Some2`,-`Some3` and `Some4` in the following modules, which you need to import so as to-bring to scope the desired instances at their usage site:--* Package `exinst`, module `Exinst.Instances.Base`: Instances for various-  type-classes found in the `base` package: `Eq`, `Ord`, `Show`.--* Package `exinst-aeson`, module `Exinst.Instances.Aeson`: Instances for-  `FromJSON` and `ToJSON` from the `aeson` package.--* Package `exinst-bytes`, module `Exinst.Instances.Bytes`: Instances for-  `Serial` from the `bytes` package.--* Package `exinst-hashable`, module `Exinst.Instances.Hashable`: Instances for-  `Hashable` from the `hashable` package.--* Package `exinst-deepseq`, module `Exinst.Instances.DeepSeq`: Instances for-  `NFData` from the `deepseq` package.--You are invited to read the instance heads for said instances so as to understand-what you need to provide in order to get those instances “for free”. As a rule of-thumb, most instances will require this: If you expect to have an instance for-`class Y => Z a` satisfied for `Some1 (f :: k -> *)`, then make sure an instance-for `Z` is available for the `DemoteRep ('KProxy :: KProxy k)`, that a `Dict1 Z-(f :: k -> *)` or more general instance exists, and that the `Y` instance for-`Some1 (f :: k -> *)` exists too.--> TODO: Have something similar to `Dict1` and friends for working with-> non-singleton types, possibly integrating with 'Data.Constraint.Forall.ForallT'-> if it made sense to do so.--Here is the full code needed to have, say, the `Eq`, `Show`, `ToJSON` and-`FromJSON` instances available for `Some1 Receptacle`:--```haskell-{-# LANGUAGE ConstraintKinds #-}-{-# LANGUAGE DataKinds #-}-{-# LANGUAGE FlexibleInstances #-}-{-# LANGUAGE GADTs #-}-{-# LANGUAGE KindSignatures #-}-{-# LANGUAGE MultiParamTypeClasses #-}-{-# LANGUAGE OverloadedStrings #-}-{-# LANGUAGE StandaloneDeriving #-}-{-# LANGUAGE TemplateHaskell #-}-{-# LANGUAGE TypeFamilies #-}-{-# LANGUAGE UndecidableInstances #-}--import qualified Data.Aeson as Ae-import           Data.Constraint (Dict(Dict))-import qualified Data.Singletons.TH-import           Exinst.Singletons (Dict1(dict1))---------data Size = Big | Small-  deriving (Eq, Show)--Data.Singletons.TH.genSingletons [''Size]-Data.Singletons.TH.singDecideInstances [''Size]--instance Ae.ToJSON Size where-  toJSON = \x -> case x of-    Small -> Ae.toJSON ("Small" :: String)-    Big -> Ae.toJSON ("Big" :: String)--instance Ae.FromJSON Size where-  parseJSON = Ae.withText "Size" $ \t -> case t of-     "Big" -> return Big-     "Small" -> return Small-     _ -> fail "Unknown"---instance (c (f 'Big), c (f 'Small)) => Dict1 c f where-  dict1 = \x -> case x of-    SBig -> Dict-    SSmall -> Dict---------data Receptacle (a :: Size) :: * where-  Vase :: Receptacle 'Small-  Glass :: Receptacle 'Small-  Barrel :: Receptacle 'Big--deriving instance Eq (Receptacle a)-deriving instance Show (Receptacle a)--instance Ae.ToJSON (Receptacle a) where-  toJSON = \x -> case x of-    Vase -> Ae.toJSON ("Vase" :: String)-    Glass -> Ae.toJSON ("Glass" :: String)-    Barrel -> Ae.toJSON ("Barrel" :: String)--instance Ae.FromJSON (Receptacle 'Small) where-  parseJSON = Ae.withText "Receptacle 'Small" $ \t -> case t of-     "Vase" -> return Vase-     "Glass" -> return Glass-     _ -> fail "Unknown"--instance Ae.FromJSON (Receptacle 'Big) where-  parseJSON = Ae.withText "Receptacle 'Big" $ \t -> case t of-     "Barrel" -> return Barrel-     _ -> fail "Unknown"-```--Now, provided that we import `Exinst.Instances.Base` and-`Exinst.Instances.Aeson`, `Some1 Receptacle` will have `Eq`, `Show`, `FromJSON`-and `FromJSON` instances:--```-> import Exinst.Instances.Base ()-> import Exinst.Instances.Aeson ()--> -- Trying `fromSome1`.-> fromSome1 (some1 Vase) == Just Vase-True-> fromSome1 (some1 Vase) == Just Glass-False-> fromSome1 (some1 Vase) == Just Barrel-False--> -- Trying `withSome1`-> withSome1 (some1 Vase) show-"Vase"-> withSome1 (some1 Vase) (== Vase)    -- This will fail, use `fromSome1`-                                      -- if you know you are expecting-                                      -- a `Receptacle 'Small`--> -- Trying the `Eq` instance.-> some1 Vase == some1 Vase-True-> some1 Vase == some1 Glass-False-> some1 Vase == some1 Barrel-False--> -- Trying the `Show` instance.-> show (some1 Vase)-"Some1 Small Vase"-> map show [some1 Vase, some1 Glass, some1 Barrel]-["Some1 Small Vase","Some1 Small Glass","Some1 Big Barrel"]--> -- Trying the `ToJSON` and `FromJSON` instances.-> Ae.encode (some1 Vase)-"[\"Small\",\"Vase\"]"  -- Just like in Show, the ToJSON adds some information-                        -- about the Size type-index. That's why we require-                        -- Size to provide a ToJSON instance too.-> Ae.decode (Ae.encode (some1 Vase)) == Just (some1 Vase)-True-> Ae.decode (Ae.encode (some1 Vase)) == Just (some1 Glass)-False-```---## About `Some2`, `Some3` and `Some4`.--Just like `Some1` hides the last singleton type index from fully applied-type-indexed type, `Some2` hides the last two type indexes, `Some3` hides the-last three, and `Some3` hides the last four. They can be used in the same way as-`Some1`.--Like as most instances for `Some1` require `Dict1` instances to be present for-their singleton type-index, most instances for `Some2`, `Some3` and `Some4` will-require that `Dict2`, `Dict3` or `Dict4` instances exist, respectively. Writing-these instances is very straightforward. Supposing you have a type `X :: T4 ->-T3 -> T2 -> T1 -> *` and want to existentialize all of the four type indexes yet-be able to continue using all of its instances, we can write something like-this:--```haskell-instance (c (f1 'T1a), c (f1 'T1b)) => Dict1 c (f1 :: T1 -> *) where-  dict1 = \x -> case x of { ST1a -> Dict; ST1b -> Dict }-instance (Dict1 c (f2 'T2a), Dict1 c (f2 'T2b)) => Dict2 c (f2 :: T2 -> k1 -> *) where-  dict2 = \x -> case x of { ST2a -> dict1; ST2b -> dict1 }-instance (Dict2 c (f3 'T3a), Dict2 c (f3 'T3b)) => Dict3 c (f3 :: T3 -> k2 -> k1 -> *) where-  dict3 = \x -> case x of { ST3a -> dict2; ST3b -> dict2 }-instance (Dict3 c (f4 'T4a), Dict3 c (f4 'T4b)) => Dict4 c (f4 :: T4 -> k3 -> k2 -> k1 -> *) where-  dict4 = \x -> case x of { ST4a -> dict3; ST4b -> dict3 }-```--That is, assuming the following `T1`, `T2`, `T3` and `T4`:--```haskell-data T4 = T4a | T4b-data T3 = T3a | T3b-data T2 = T2a | T2b-data T1 = T1a | T1b-```--Effectively, we wrote just one instance per singleton type per type-index-position, each of them promoting a term-level representation of a singleton-type to its type-level representation and forwarding the rest of the work to-a “smaller” dict. That is, `dict4` reifies the type of the fourth-to-last-type-index of `X` and then calls `dict3` to do the same for the third-to-last-type-index of `X` and so on. Notice, however, how we didn't need to mention `X`-in none of the instances above: As we said before, these instances are-intended to work for any choice of `c`, `f4`, `f3`, `f2` and `f1`.--> TODO: See if instead of having `Some1`, `Some2`, `Some3`, `Some4`, and their-> respective `Dict1`, `Dict2`, `Dict3` and `Dict4`, etc., we can have a single-> `SomeN` and a single `DictN` working out the number of parameters using-> type-level natural numbers.--## Converting `Some1 (f :: k -> *)` to `f (a :: k)`.--If you have a `Some1 (f :: k -> *)` and you know, statically, that you need an-specific `f (a :: k)`, then you can use `fromSome1` which will give you an-`f (a :: k)` only if `a` was the type that was existentialized by `Some1`.-Using `fromSome1` requires that the singleton type-index implements-`Data.Singletons.Decide.SDecide`, which can be derived mechanically with TH by-means of `Data.Singletons.TH.singInstance`.--If you don't know, statically, the type of `f (a :: k)`, then you can use-`withSome1Sing` or `withSome1` to work with `f (a :: k)` as long as `a` never-leaves their scope (don't worry, the compiler will yell at you if you try to do-that).---# Library implementors: Writing instances for `Some1` and friends.--Instances for `Some1` seem to come out of thin air, but the truth is that they-need to be written at least once by library authors so that, provided all its-requirements are satisfied, they are made available.--When we imported `Exinst.Instances.Base` before, we brought to scope, among-other things, the `Show` instance for `Some1`, which is defined as this:--```haskell--- Internal wrapper so that we don't have to write the string manipulation parts--- in the 'Show' instance by hand.-data Some1'Show r1 x = Some1 r1 x deriving (Show)--instance forall (f1 :: k1 -> *)-  . ( SingKind ('KProxy :: KProxy k1)-    , Show (DemoteRep ('KProxy :: KProxy k1))-    , Dict1 Show f1-    ) => Show (Some1 f1)-  where-    showsPrec n = \some1 -> withSome1Sing some1 $ \sa1 (x :: f1 a1) ->-       case dict1 sa1 :: Dict (Show (f1 a1)) of-          Dict -> showsPrec n (Some1 (fromSing sa1) x)-```--This code should be relatively straightforward if you are familiar with uses of-the `singletons` and `constraints` libraries. We are simply reifying singleton-types from their term-level representation to their type-level representation,-and afterwards using the `Dict1` mechanism to lookup the required instances-during runtime. Additionaly, this instance requires that the term level-representation of the singleton type implements `Show` too, as, like we saw in a-previous example, the type index itself is shown in this `Show` implementation,-in the hope that it can be later recovered and reified to the type level when-using `Read`.---# Related work on Generic instances for GADTs+See the [BSD3 LICENSE](https://github.com/k0001/exinst/blob/master/exinst/exinst/LICENSE.txt)+file to learn about the legal terms and conditions for this library. -One of the most appealing applications of `exinst` is to reduce the boilerplate-associated with manually writing instances for existentialized GADTs. However,-quite often, writing instances for said GADTs on its own is very cumbersome-due to the lack of generic instance deriving mechanisms for GADTs. There exists,-however, at the time of this writing, at least one library able to derive-generic representations for some GADTs using TH:-[`instant-generics`](https://hackage.haskell.org/package/instant-generics).+Find documentation for this library in the top-level+[`Exinst`](https://github.com/k0001/exinst/blob/master/exinst/lib/Exinst.hs)+module. -Combining [`instant-generics`](https://hackage.haskell.org/package/instant-generics) (and-[`instant-aeson`](https://hackage.haskell.org/package/instant-aeson),-[`instant-hashable`](https://hackage.haskell.org/package/instant-hashable),-[`instant-bytes`](https://hackage.haskell.org/package/instant-bytes) and-[`instant-deepseq`](https://hackage.haskell.org/package/instant-deepseq))-with [`exinst`](https://hackage.haskell.org/package/exinst) (and-[`exinst-aeson`](https://hackage.haskell.org/package/exinst-aeson),-[`exinst-hashable`](https://hackage.haskell.org/package/exinst-hashable),-[`exinst-bytes`](https://hackage.haskell.org/package/exinst-bytes) and-[`exinst-deepseq`](https://hackage.haskell.org/package/exinst-deepseq)),-you can reduce a lot of the boilerplate associated with working with GADTs, in-particular when it comes to the serialization and deserialization of them (i.e.,-`Show` and `Read`, or `ToJSON` and `FromJSON`) or puting GADTs in monomorphic-containers (i.e., `[]` or `HashMap`), which become straightforward things to do-once you are able able to both generically derive the instances for your GADT-and then existentialize away the type-index while keeping the underlying-instances available.
− Setup.hs 
@@ -1,2 +0,0 @@-import Distribution.Simple-main = defaultMain
exinst.cabal view
@@ -1,29 +1,40 @@ name:                exinst-version:             0.2+version:             0.9 author:              Renzo Carbonara-maintainer:          renzoλcarbonara.com.ar-copyright:           Renzo Carbonara 2015-2016+maintainer:          renλren!zone+copyright:           Renzo Carbonara 2015 license:             BSD3 license-file:        LICENSE.txt extra-source-files:  README.md CHANGELOG.md category:            Data build-type:          Simple-cabal-version:       >=1.18-synopsis:            Derive instances for your existential types.+cabal-version:       1.18+synopsis:            Dependent pairs and their instances. homepage:            https://github.com/k0001/exinst bug-reports:         https://github.com/k0001/exinst/issues   library-  hs-source-dirs: src/lib+  hs-source-dirs: lib   default-language: Haskell2010   exposed-modules:-      Exinst.Singletons-      Exinst.Instances.Base+      Exinst+  other-modules:+      Exinst.Internal+      Exinst.Internal.Product+      Exinst.Internal.Sum+      Exinst.Binary+      Exinst.DeepSeq+      Exinst.Hashable+      Exinst.QuickCheck   build-depends:       base >=4.9 && <5.0-    , constraints >=0.4 && <0.9-    , profunctors >=5.0 && <6.0-    , singletons >=2.2 && <2.3+    , binary+    , constraints >=0.4+    , deepseq+    , hashable+    , profunctors >=5.0+    , singletons >= 3.0+    , QuickCheck   ghcjs-options: -Wall -O3   ghc-options: -Wall -O2
+ lib/Exinst.hs view
@@ -0,0 +1,669 @@+{-# LANGUAGE CPP #-}++{- |++Exinst is a library providing you with tools to recover type-indexed types whose+type-indexes have been existentialized, as well as automatically deriving+instances for them, as long as said type indexes are singleton types+(see [singleton](https://hackage.haskell.org/package/singletons)).++In short, what @exinst@ currently gives you is: For any type @t :: k -> *@, if+@k@ is a singleton type and @c (t a) :: 'Constraint'@ is satisfied, then you can+existentialize away the @a@ parameter with @'Some1' t@, recover it later, and+have @c ('Some1' t)@ automatically satisfied. Currently, up to 4 type indexes+can be existentialized using 'Some1', 'Some2', 'Some3' and 'Some4' respectively.++NOTE: This tutorial asumes some familiarity with singleton types as implemented+by the [singleton](https://hackage.haskell.org/package/singletons) library.+A singleton type is, in very rough terms, a type inhabited by a single term,+which allows one to go from its term-level representation to its type-level+representation and back without much trouble. A bit like the term @()@, which+is of type @()@. Whenever you have the type @()@ you know what that its+term-level representation must be @()@, and whenever you have the term @()@+you know that its type must be @()@.++-}++module Exinst+ ( -- * Tutorial+   -- $motivation++   -- *** Usage+   -- $usage++   -- *** Recovering+   -- $recovering++   -- *** Many indexes+   -- $manyIndexes++   -- *** Writing instances+   -- $writingInstances++   -- *** Products and sums+   -- $prodsums++   -- * 1 type index+   Some1(Some1)+ , some1+ , fromSome1+ , _Some1+ , withSome1+ , withSome1Sing+ , some1SingRep+ , same1+ , Dict1(dict1)++   -- * 2 type indexes+ , Some2(Some2)+ , some2+ , fromSome2+ , _Some2+ , withSome2+ , withSome2Sing+ , some2SingRep+ , same2+ , Dict2(dict2)++   -- * 3 type indexes+ , Some3(Some3)+ , some3+ , fromSome3+ , _Some3+ , withSome3+ , withSome3Sing+ , some3SingRep+ , same3+ , Dict3(dict3)++   -- * 4 type indexes+ , Some4(Some4)+ , some4+ , fromSome4+ , _Some4+ , withSome4+ , withSome4Sing+ , some4SingRep+ , same4+ , Dict4(dict4)++   -- * Miscellaneous+ , Dict0(dict0)++   -- * Products+ , P1(P1)+ , P2(P2)+ , P3(P3)+ , P4(P4)++   -- * Sums+ , S1(S1L,S1R)+ , S2(S2L,S2R)+ , S3(S3L,S3R)+ , S4(S4L,S4R)++   -- * Re-exports+ , Constraint+ , Dict(Dict)+ , Sing+ , SingI+ ) where++import Data.Constraint (Constraint, Dict(Dict))++import Data.Singletons (Sing, SingI)++import Exinst.Internal+import Exinst.Internal.Product+import Exinst.Internal.Sum++import Exinst.Binary ()+import Exinst.DeepSeq ()+import Exinst.Hashable ()+import Exinst.QuickCheck ()++{- $motivation++As a motivation, let's consider the following example:++@+\{\-\# LANGUAGE GADTs \#\-\}+\{\-\# LANGUAGE DataKinds \#\-\}+\{\-\# LANGUAGE KindSignatures \#\-\}+\{\-\# LANGUAGE FlexibleInstances \#\-\}+\{\-\# LANGUAGE StandaloneDeriving \#\-\}++data Size = Big | Small++data Receptacle (a :: Size) :: * where+  Vase :: Receptacle 'Small+  Glass :: Receptacle 'Small+  Barrel :: Receptacle 'Big++deriving instance 'Show' (Receptacle a)+@++@Receptacle@ can describe three types of receptacles (@Vase@, @Glass@ and+@Barrel@), while at the same time being able to indicate, at the type level,+whether the size of the receptacle is @Big@ or @Small@. Additionally, we've+provided 'Show' instances for @Receptacle@.++Now, if we want to put @Receptacle@s in a container, for example in @[]@, we can+do so only as long as the @Receptacle@ type is fully applied and monomorphic.+That is, we can have @[Receptacle 'Small]@ and @[Receptacle 'Big]@, but we+can't have @[Receptacle]@ nor @[forall a. Receptacle a]@. So, if we want to+have @Receptacle@s of different sizes in a container like @[]@, we need a+different solution.++At this point we need to ask ourselves why we need to put @Receptacle@s of+different sizes in a same container. If the answer is something like “because we+want to show all of them, no matter what size they are”, then we should realize+that what we are actually asking for is that no matter what @Size@ our+@Receptable@ has, we need to be able to find a 'Show' instance for that+@Receptacle@. In Haskell, we can express just that using existential types+and constraints hidden behind a data constructor.++@+-- We need to add these language extensions to the ones in the previous example+\{\-\# LANGUAGE ExistentialQuantification \#\-\}+\{\-\# LANGUAGE FlexibleContexts \#\-\}++data ReceptacleOfAnySizeThatCanBeShown+  = forall a. ('Show' (Receptacle a))+      => MkReceptacleOfAnySizeThatCanBeShown (Receptacle a)+@++We can construct values of type @ReceptacleOfAnySizeThatCanBeShown@ only as long+as there exist a 'Show' instance for the @Receptacle a@ we give to the+@MkReceptacleOfAnySizeThatCanBeShown@ constructor. In our case, both @Receptacle+'Small@ and @Receptacle 'Big@ have 'Show' instances, so all of @Vase@, @Glass@ and+@Barrel@ can be used successfully with @MkReceptacleOfAnySizeThatCanBeShown@.++Now, @ReceptacleOfAnySizeThatCanBeShown@ on itself doesn't yet have a 'Show'+instance, and we can't derive one automatically using the @deriving@ mechanism,+but we can give an explicit 'Show' instance that just forwards the work to the+'Show' instance of the underlying @Receptacle a@.++@+instance 'Show' ReceptacleOfAnySizeThatCanBeShown where+  'show' (MkReceptacleOfAnySizeThatCanBeShown a) = 'show' a+@++That works as intended:++@+> 'show' (MkReceptacleOfAnySizeThatCanBeShown Vase)+"Vase"+> 'show' (MkReceptacleOfAnySizeThatCanBeShown Barrel)+"Barrel"+@++And now, as we wanted, we can put @Receptacle@s of different sizes in a @[]@ and+show them (as long as we wrap each of them as+@ReceptacleOfAnySizeThatCanBeShown@, that is).++@+> 'map' 'show' [MkReceptacleOfAnySizeThatCanBeShown Vase, MkReceptacleOfAnySizeThatCanBeShown Barrel]+["Vase", "Barrel"]+@++However, the above solution is unsatisfying for various reasons: For one, the+'Show' instance for @ReceptacleOfAnySizeThatCanBeShown@ works only as long as+the @ReceptacleOfAnySizeThatCanBeShown@ itself carries a witness that the 'Show'+constraint for @Receptacle a@ is satisfied, which means that if we want to write+yet another instance for @ReceptacleOfAnySizeThatCanBeShown@ that simply forwards+its implementation to the underlying @Receptacle a@, say 'Eq', then the+@MkReceptacleOfAnySizeThatCanBeShown@ constructor would need to be modified to witness+the @Eq (Receptacle a)@ instance too:++@+data ReceptacleOfAnySizeThatCanBeShown+  = forall a. ('Show' (Receptacle a), 'Eq' (Receptacle a))+      => MkReceptacleOfAnySizeThatCanBeShown (Receptacle a)+@++With that in place we can provide an 'Eq' instance for+@ReceptacleOfAnySizeThatCanBeShown@ as we did for 'Show' before, but if we pay+close attention, we can see how the implementation of+@ReceptacleOfAnySizeThatCanBeShown@ starts to become a bottleneck: Every+instance we want to provide for @ReceptacleOfAnySizeThatCanBeShown@ that simply+forwards its work to the underlying @Receptacle a@ needs to be witnessed by+@MkReceptacleOfAnySizeThatCanBeShown@ itself, it is not enough that there exists+an instance for @Receptacle a@. Moreover, even the name+@ReceptacleOfAnySizeThatCanBeShown@ that we chose before isn't completely+accurate anymore, and will become less and less accurate as we continue adding+constraints to @MkReceptacleOfAnySizeThatCanBeShown@.++Additionally, everywhere we use the @MkReceptacleOfAnySizeThatCanBeShown@+constructor we need to witness that the existentialized @Receptacle a@ satisfies+all the required constraints, which means that, if the @Receptacle a@ we pass to+@MkReceptacleOfAnySizeThatCanBeShown@ is being received, say, as a parameter to+a function, then the type of that function will also require that its caller+satisfies all of the same constraints, even though it is obvious to us,+statically, that the instances exist. We can now see how all of this becomes+unmanegeable, or at least very *boilerplatey*, as those constraints start to+propagate through our code base.++What we need is a way for instances such as the 'Show' instance for+@ReceptacleOfAnySizeThatCanBeShown@ to find the 'Show' instance for @Receptacle+a@ without it being explicitely witnessed by the+@MkReceptacleOfAnySizeThatCanBeShown@ constructor. That is exactly the problem+that @exinst@ solves: allowing /exi/stentials to find their /inst/ances. Thus,+the name of this library.++-}++{- $usage++Given the code for @Size@, @Receptacle@ and its 'Show' instances above, we can+achieve the same functionality as our initial @ReceptacleOfAnySizeThatCanBeShown@ by+existentializing the type indexes of @Receptacle 'Small@ and @Receptacle 'Big@+as @'Some1' Receptacle@. In order to do that, we must first ensure that @Size@ and its+constructors can be used as singleton types (as supported by the @singletons@ library),+for which we can use some @TemplateHaskell@ provided by @Data.Singletons.TH@:++@+import qualified "Data.Singletons.TH"++Data.Singletons.TH.genSingletons [''Size]+@++And we'll also need a 'Show' instance for @Size@ for reasons that will become+apparent later:++@+deriving instance 'Show' Size+@++Now we can construct a @Show1 Size@ and 'show' achieving the same results as we+did with @ReceptacleOfAnySizeThatCanBeShown@ before.++Note: this code won't work yet. Keep reading.++@+> import "Exinst" ('Some1', 'some1')+> :t 'some1' Glass+:t 'some1' Glass :: 'Some1' Receptacle+> 'show' ('some1' Glass)+"Some1 Small Glass"+@++Well, actually, the default 'Show' instance for 'Some1' shows a bit more of+information, as it permits this string to be 'Read' back into a @'Some1'+Receptacle@ if needed, but displaying just @"Glass"@ would be possible too, if+desired.++The important thing to notice in the example above is that @some1@ does not+require us to satisfy a @'Show' (Receptacle 'Small)@ constraint, it just requires+that the type index for the type-indexed type we give it as argument is a+singleton type:++@+'some1' :: forall (f1 :: k1 -> *) (a1 :: k1). 'SingI' a1 => f1 a1 -> 'Some1' f1+@++It is the application of 'show' to @'some1' Glass@ which will fail to compile if+there isn't a 'Show' instance for @Receptacle 'Small@, complaining that a 'Show'+instance for @'Some1' Receptable@ can't be found. The reason for this is that even+if 'Show' instances for 'Some1' are derived for free, they are only derived for+@'Some1' (t :: k1 -> *)@ where a @'Show' (t a)@ for a specific but statically+unknown @a@ can be found at runtime (mostly, there are other minor requirements too).+The mechanism through which instances are found at runtime relies on 'Dict' from+the [constraints](https://hackage.haskell.org/package/constraints) library, which+@exinst@ wraps in a 'Dict1' typeclass to be instantiated once per singleton+type.++@+-- The "Exinst.Dict1" class+class 'Dict1' (c :: k0 -> 'Constraint') (f1 :: k1 -> k0) where+  'dict1' :: 'Sing' (a1 :: k1) -> 'Dict' (c (f1 a1))+@++What 'Dict1' says is that: for a type-indexed type @f1@, given a term-level+representation of the singleton type that indexes said @f1@, we can obtain a+witness that the constraint @c@ is satisfied by @f1@ applied to the singleton+type.++That class seems to be a bit too abstract, but the instances we as users need to+write for it are quite silly and straightforward.++Here's an example of how to provide 'Show' support for @'Some1' Receptacle@ via+'Dict1':++@+instance ('Show' (Receptacle 'Small), 'Show' (Receptacle 'Big)) => 'Dict1' 'Show' Receptacle where+  'dict1' = \x -> case x of+    SSmall -> 'Dict'+    SBig -> 'Dict'+@++The implementation of @dict1@ looks quite silly, but it has to look like that as+it is only by pattern-matching on each of the @'Sing' Size@ constructors that we+learn about the type level representation of a singleton type, which we then use+to select the proper 'Show' instance among all of those listed in the instance head.++Given this 'Dict1' instance, we can proceed to excecute the REPL example mentioned before+and it will work just fine.++However, that 'Dict1' instance is still a bit insatisfactory: If we wanted,+again, to provide 'Eq' support for our @'Some1' Receptacle@ type, we would need to+write yet another 'Dict1' instance like the one above, but mentioning 'Eq'+instead of 'Show'. We can do better.++The trick, when writing 'Dict1' instances such as the one above, is to leave @c@+and @f1 :: k1 -> k0@ completely polymorphic, and instead only talk concretely+about the singleton type with kind @k1@. This might sound strange at first, as+@c@ and @f1@ are the only two type parameters to 'Dict1'. But as it often happens+when working with singleton types, we are not particularly interested in the+types involved, but in their kinds instead. So, this is the 'Dict1' instance+you often want to write:++@+instance (c (f1 'Small), c (f1 'Big)) => 'Dict1' c (f1 :: Size -> k0) where+  'dict1' = \x -> case x of+    SSmall -> 'Dict'+    SBig -> 'Dict'+@++That instance says that for any choice of @c@ and @f1 :: Size -> k0@, if an+instance for @c (f1 a)@ exists for a specific choice of @a@, then, given a term+level representation for that @a@ and the aid of @dict1@, said instance can be+looked up at runtime.++Notice that 'Some1' itself doesn't have any requirements about 'Dict1', it's the+various instances for 'Some1' who rely on 'Dict1'. 'Dict1' has nothing to do+with 'Some1', nor with the choice of @f@ nor with the choice of @c@; it is only+related to the singleton type used as a type-index for @f@.++The @Exinst@ module exports ready-made instances for 'Some1', 'Some2', 'Some3'+and 'Some4'.++* 'Data.Binary.Binary' from the @binary@ package.++* 'Data.Hashable.Hashable' from the @hashable@ package.++* 'Control.DeepSeq.NFData' from the @deepseq@ package.++* 'Test.QuickCheck.Arbitrary' from the @QuickCheck@ package.++Furthermore, other libraries export other orphan instances for the datatypes+exported by 'exinst':++* [exinst-base](https://hackage.haskell.org/package/exinst-aeson) exports+instances for 'Show', 'Read', 'Eq', 'Ord' and 'Generic' from the @base@+package. Depends on the large @singleton-base@ package, that's why+these instances are not in the @exinst@ package itself.++* [exinst-aeson](https://hackage.haskell.org/package/exinst-aeson) exports+instances for 'Data.Aeson.FromJSON' and 'Data.Aeson.ToJSON' from the @aeson@+package.++* [exinst-bytes](https://hackage.haskell.org/package/exinst-bytes) exports+instances for 'Data.Bytes.Serial' from the @bytes@ package.++* [exinst-cereal](https://hackage.haskell.org/package/exinst-cereal) exports+instances for 'Cereal.Serialize.Serialize' from the @cereal@ package.++* [exinst-serialise](https://hackage.haskell.org/package/exinst-serialise)+exports instances for 'Codec.Serialise.Serialise' from the @serialise@ package.+++You are invited to read the instance heads for said instances so as to understand+what you need to provide in order to get those instances “for free”. As a rule of+thumb, most instances will require this: If you expect to have an instance for+@class Y => Z a@ satisfied for @'Some1' (f :: k1 -> *)@, then make sure an instance+for @Z@ is available for the @DemoteRep k1@, that a @'Dict1' Z (f :: k1 -> k0)@ or+more general instance exists, and that the @Y@ instance for @'Some1' (f :: k1 ->+*)@ exists too.++Here is the full code needed to have, say, the 'Eq' and 'Show' instances+available for @'Some1' Receptacle@:++@+\{\-\# LANGUAGE ConstraintKinds \#\-\}+\{\-\# LANGUAGE DataKinds \#\-\}+\{\-\# LANGUAGE FlexibleInstances \#\-\}+\{\-\# LANGUAGE GADTs \#\-\}+\{\-\# LANGUAGE KindSignatures \#\-\}+\{\-\# LANGUAGE MultiParamTypeClasses \#\-\}+\{\-\# LANGUAGE OverloadedStrings \#\-\}+\{\-\# LANGUAGE StandaloneDeriving \#\-\}+\{\-\# LANGUAGE TemplateHaskell \#\-\}+\{\-\# LANGUAGE TypeFamilies \#\-\}+\{\-\# LANGUAGE UndecidableInstances \#\-\}++import qualified "Data.Singletons.TH"+import           "Exinst" ('Dict'('Dict'), 'Dict1'('dict1'))++data Size = Big | Small+  deriving ('Eq', 'Show')++Data.Singletons.TH.genSingletons [''Size]+Data.Singletons.TH.singDecideInstances [''Size]++instance (c (f 'Big), c (f 'Small)) => 'Dict1' c f where+  'dict1' = \x -> case x of+    SBig -> 'Dict'+    SSmall -> 'Dict'+++data Receptacle (a :: Size) :: * where+  Vase :: Receptacle 'Small+  Glass :: Receptacle 'Small+  Barrel :: Receptacle 'Big++deriving instance 'Eq' (Receptacle a)+deriving instance 'Show' (Receptacle a)+@++Now, @'Some1' Receptacle@ will have 'Eq' and 'Show' instances:++@+> -- Trying 'fromSome1'.+> 'fromSome1' ('some1' Vase) == 'Just' Vase+'True'+> 'fromSome1' ('some1' Vase) == 'Just' Glass+'False'+> 'fromSome1' ('some1' Vase) == 'Just' Barrel+'False'++> -- Trying 'withSome1'+> 'withSome1' ('some1' Vase) 'show'+"Vase"+> 'withSome1' ('some1' Vase) (== Vase)    -- This will fail, use 'fromSome1'+                                      -- if you know you are expecting+                                      -- a @Receptacle 'Small@++> -- Trying the 'Eq' instance.+> 'some1' Vase == 'some1' Vase+'True'+> 'some1' Vase == 'some1' Glass+'False'+> 'some1' Vase == 'some1' Barrel+'False'++> -- Trying the 'Show' instance.+> 'show' ('some1' Vase)+"Some1 Small Vase"+> 'map' 'show' ['some1' Vase, 'some1' Glass, 'some1' Barrel]+["Some1 Small Vase","Some1 Small Glass","Some1 Big Barrel"]+@++-}++{- $manyIndexes++Just like 'Some1' hides the last singleton type index from fully applied+type-indexed type, 'Some2' hides the last two type indexes, 'Some3' hides the+last three, and 'Some3' hides the last four. They can be used in the same way as+'Some1'.++Like as most instances for 'Some1' require 'Dict1' instances to be present for+their singleton type-index, most instances for 'Some2', 'Some3' and 'Some4' will+require that 'Dict2', 'Dict3' or 'Dict4' instances exist, respectively. Writing+these instances is very straightforward. Supposing you have a type @X :: T4 ->+T3 -> T2 -> T1 -> *@ and want to existentialize all of the four type indexes yet+be able to continue using all of its instances, we can write something like+this:++@+instance (c (f1 'T1a), c (f1 'T1b)) => 'Dict1' c (f1 :: T1 -> k0) where+  'dict1' = \x -> case x of { ST1a -> 'Dict'; ST1b -> 'Dict' }+instance ('Dict1' c (f2 'T2a), 'Dict1' c (f2 'T2b)) => 'Dict2' c (f2 :: T2 -> k1 -> k0) where+  'dict2' = \x -> case x of { ST2a -> 'dict1'; ST2b -> 'dict1' }+instance ('Dict2' c (f3 'T3a), 'Dict2' c (f3 'T3b)) => 'Dict3' c (f3 :: T3 -> k2 -> k1 -> k0) where+  'dict3' = \x -> case x of { ST3a -> 'dict2'; ST3b -> 'dict2' }+instance ('Dict3' c (f4 'T4a), 'Dict3' c (f4 'T4b)) => 'Dict4' c (f4 :: T4 -> k3 -> k2 -> k1 -> k0) where+  'dict4' = \x -> case x of { ST4a -> 'dict3'; ST4b -> 'dict3' }+@++That is, assuming the following @T1@, @T2@, @T3@ and @T4@:++@+data T4 = T4a | T4b+data T3 = T3a | T3b+data T2 = T2a | T2b+data T1 = T1a | T1b+@++Effectively, we wrote just one instance per singleton type per type-index+position, each of them promoting a term-level representation of a singleton+type to its type-level representation and forwarding the rest of the work to+a “smaller” dict. That is, 'dict4' reifies the type of the fourth-to-last+type-index of @X@ and then calls 'dict3' to do the same for the third-to-last+type-index of @X@ and so on. Notice, however, how we didn't need to mention @X@+in none of the instances above: As we said before, these instances are+intended to work for any choice of @c@, @f4@, @f3@, @f2@ and @f1@.++-}++{- $recovering++If you have a @'Some1' (f :: k -> *)@ and you know, statically, that you need an+specific @f (a :: k)@, then you can use 'fromSome1' which will give you an+@f (a :: k)@ only if @a@ was the type that was existentialized by 'Some1'.+Using 'fromSome1' requires that the singleton type-index implements+'Data.Singletons.Decide.SDecide', which can be derived mechanically with+`TemplateHaskell` by means of 'Data.Singletons.TH.singInstance'.++If you don't know, statically, the type of @f (a :: k)@, then you can use+'withSome1Sing' or 'withSome1' to work with @f (a :: k)@ as long as @a@ never+leaves their scope (don't worry, the compiler will yell at you if you try to do+that).++-}+++{- $prodsums++Consider the following types and constructors:++@+data X (a :: 'Bool') where+  XT :: X ''True'+  XF :: X ''False'++data Y (a :: 'Bool') where+  YT :: Y ''True'+  YF :: Y ''False'+@++You can use '(,)' to create a product for values of this type, and 'Either' to+create a sum. However, see what happens if we try to existentialize the type+index when using that approach:++@+> :t ('some1' XT, 'some1' YT)+('some1' XT, 'some1' YT) :: ('Some1' X, 'Some1' Y)+> :t ('some1' XT, 'some1' YF)+('some1' XT, 'some1' YF) :: ('Some1' X, 'Some1' Y)+@++It works, but there is no type level guarantee that the type index taken by @X@+and @Y@ is the same. If you do want to enforce that restriction, then you can+use @P1@ instead:++@+> :t 'P1'+'P1' :: l a -> r a -> 'P1' l r (a :: k)+> :t 'P1' XT YT+'P1' XT YT :: 'P1' X Y ''True'+> :t 'P1' XT YT+'P1' XT YT :: 'P1' X Y ''True'+> :t 'some1' ('P1' XT YT)+'some1' ('P1' XT YT) :: 'Some1' ('P1' X Y)+@++Trying to mix @XT@ with @YF@ fails, of course, since they have different type+indexes:++@+> :t 'P1' XT YF+\<interactive\>:1:7: error:+    • Couldn't match type ‘''False'’ with ‘''True'’+      Expected type: Y ''True'+        Actual type: Y ''False'+    • In the second argument of ‘'P1'’, namely ‘YF’+      In the expression: 'P1' XT YF+@++Moreover, 'P1' supports many common instances from @base@, @hashable@,+@deepseq@, @aeson@, @bytes@, @cereal@, @binary@ and @quickcheck@ out of the+box, so you can benefit from them as well.++There's also 'P2', 'P3' and 'P4' for product types taking a different number of+indexes, and also 'S1', 'S2', 'S3' and 'S4' for sum types:++@+> :t 'S1L'+'S1L' :: l a -> 'S1' l r (a :: k)+> :t 'S1R'+'S1R' :: r a -> 'S1' l r (a :: k)+> :t 'S1L' XT+'S1L' XT :: 'S1' X r ''True'+> :t 'S1R' YT+'S1R' YT :: 'S1' l Y ''True'+> :t 'some1' ('S1L' XT)+'some1' ('S1L' XT) :: 'Some1' ('S1' X r)+> :t 'some1' ('S1R' YT)+'some1' ('S1R' YT) :: 'Some1' ('S1' l Y)+@++-}+++{- $writingInstances++Instances for 'Some1' seem to come out of thin air, but the truth is that they+need to be written at least once by library authors so that, provided all its+requirements are satisfied, they are made available.++For example, when we imported "Exinst" before, we also brought to scope, among+other things, the 'Eq' instance for 'Some1', which is defined as this:++@+instance forall (f :: k1 -> *).+  ( 'Data.Singletons.Decide.SDecide' k1+  , 'Dict1' 'Eq' f+  ) => 'Eq' ('Some1' f)+  where+  (==) = \\som1x som1y ->+     'withSome1Sing' som1x $ \\sa1x (x :: f a1x) ->+        'withSome1Sing' som1y $ \\sa1y (y :: f a1y) ->+           'maybe' 'False' 'id' $ do+              'Data.Type.Equality.Refl' <- 'Data.Type.Equality.testEquality' sa1x sa1y+              case 'dict1' sa1x :: 'Dict' ('Eq' (f a1x)) of+                 'Dict' -> 'Just' (x == y)+@++This code should be relatively straightforward if you are familiar with uses of+the @singletons@ and @constraints@ libraries. We are simply reifying singleton+types from their term-level representation to their type-level representation,+and afterwards using the 'Dict1' mechanism to lookup the required instances+during runtime. Additionaly, this instance requires that the term level+representation of the singleton type implements 'Show' too, as, like we saw in a+previous example, the type index itself is shown in this 'Show' implementation,+in the hope that it can be later recovered and reified to the type level when+using 'Read'.++-}
+ lib/Exinst/Binary.hs view
@@ -0,0 +1,156 @@+{-# LANGUAGE DataKinds #-}+{-# LANGUAGE FlexibleContexts #-}+{-# LANGUAGE PolyKinds #-}+{-# LANGUAGE ScopedTypeVariables #-}+{-# LANGUAGE TypeInType #-}+{-# LANGUAGE UndecidableInstances #-}++{-# OPTIONS_GHC -fno-warn-orphans #-}++-- | This module exports 'Bin.Binary' instances for 'Some1', 'Some2', 'Some3'+-- and 'Some4' from "Exinst", provided situable 'Dict1', 'Dict2',+-- 'Dict3' and 'Dict4' instances are available.+--+-- See the README file in the @exinst@ package for more general documentation:+-- https://hackage.haskell.org/package/exinst#readme+module Exinst.Binary () where++import qualified Data.Binary as Bin+import Data.Constraint+import Data.Kind (Type)+import Data.Singletons+import Prelude++import Exinst.Internal+import Exinst.Internal.Sum+import Exinst.Internal.Product++--------------------------------------------------------------------------------++-- | Compatible with the 'Data.Bytes.Serial.Serial' instance and+-- 'Data.Serialize.Serialize' instance, provided all of the 'Demote's and the+-- fully applied @f@ instances are compatible as well.+instance forall k1 (f :: k1 -> Type).+  ( SingKind k1+  , Bin.Binary (Demote k1)+  , Dict1 Bin.Binary f+  ) => Bin.Binary (Some1 f) where+  {-# INLINABLE put #-}+  put = \some1x ->+    withSome1Sing some1x $ \sa1 (x :: f a1) ->+      case dict1 sa1 :: Dict (Bin.Binary (f a1)) of+        Dict -> do+          Bin.put (fromSing sa1)+          Bin.put x+  {-# INLINABLE get #-}+  get = do+    rsa1 <- Bin.get+    withSomeSing rsa1 $ \(sa1 :: Sing (a1 :: k1)) ->+      case dict1 sa1 :: Dict (Bin.Binary (f a1)) of+        Dict -> do+          x :: f a1 <- Bin.get+          pure (Some1 sa1 x)++-- | Compatible with the 'Data.Bytes.Serial.Serial' instance and+-- 'Data.Serialize.Serialize' instance, provided all of the 'Demote's and the+-- fully applied @f@ instances are compatible as well.+instance forall k2 k1 (f :: k2 -> k1 -> Type).+  ( SingKind k2+  , SingKind k1+  , Bin.Binary (Demote k2)+  , Bin.Binary (Demote k1)+  , Dict2 Bin.Binary f+  ) => Bin.Binary (Some2 f) where+  {-# INLINABLE put #-}+  put = \some2x ->+    withSome2Sing some2x $ \sa2 sa1 (x :: f a2 a1) ->+      case dict2 sa2 sa1 :: Dict (Bin.Binary (f a2 a1)) of+        Dict -> do+          Bin.put (fromSing sa2, fromSing sa1)+          Bin.put x+  {-# INLINABLE get #-}+  get = do+    (rsa2, rsa1) <- Bin.get+    withSomeSing rsa2 $ \(sa2 :: Sing (a2 :: k2)) ->+      withSomeSing rsa1 $ \(sa1 :: Sing (a1 :: k1)) ->+        case dict2 sa2 sa1 :: Dict (Bin.Binary (f a2 a1)) of+          Dict -> do+            x :: f a2 a1 <- Bin.get+            pure (Some2 sa2 sa1 x)++-- | Compatible with the 'Data.Bytes.Serial.Serial' instance and+-- 'Data.Serialize.Serialize' instance, provided all of the 'Demote's and the+-- fully applied @f@ instances are compatible as well.+instance forall k3 k2 k1 (f :: k3 -> k2 -> k1 -> Type).+  ( SingKind k3+  , SingKind k2+  , SingKind k1+  , Bin.Binary (Demote k3)+  , Bin.Binary (Demote k2)+  , Bin.Binary (Demote k1)+  , Dict3 Bin.Binary f+  ) => Bin.Binary (Some3 f) where+  {-# INLINABLE put #-}+  put = \some3x ->+    withSome3Sing some3x $ \sa3 sa2 sa1 (x :: f a3 a2 a1) ->+      case dict3 sa3 sa2 sa1 :: Dict (Bin.Binary (f a3 a2 a1)) of+        Dict -> do+          Bin.put (fromSing sa3, fromSing sa2, fromSing sa1)+          Bin.put x+  {-# INLINABLE get #-}+  get = do+    (rsa3, rsa2, rsa1) <- Bin.get+    withSomeSing rsa3 $ \(sa3 :: Sing (a3 :: k3)) ->+      withSomeSing rsa2 $ \(sa2 :: Sing (a2 :: k2)) ->+        withSomeSing rsa1 $ \(sa1 :: Sing (a1 :: k1)) ->+          case dict3 sa3 sa2 sa1 :: Dict (Bin.Binary (f a3 a2 a1)) of+            Dict -> do+              x :: f a3 a2 a1 <- Bin.get+              pure (Some3 sa3 sa2 sa1 x)++-- | Compatible with the 'Data.Bytes.Serial.Serial' instance and+-- 'Data.Serialize.Serialize' instance, provided all of the 'Demote's and the+-- fully applied @f@ instances are compatible as well.+instance forall k4 k3 k2 k1 (f :: k4 -> k3 -> k2 -> k1 -> Type).+  ( SingKind k4+  , SingKind k3+  , SingKind k2+  , SingKind k1+  , Bin.Binary (Demote k4)+  , Bin.Binary (Demote k3)+  , Bin.Binary (Demote k2)+  , Bin.Binary (Demote k1)+  , Dict4 Bin.Binary f+  ) => Bin.Binary (Some4 f) where+  {-# INLINABLE put #-}+  put = \some4x ->+    withSome4Sing some4x $ \sa4 sa3 sa2 sa1 (x :: f a4 a3 a2 a1) ->+      case dict4 sa4 sa3 sa2 sa1 :: Dict (Bin.Binary (f a4 a3 a2 a1)) of+        Dict -> do+          Bin.put (fromSing sa4, fromSing sa3, fromSing sa2, fromSing sa1)+          Bin.put x+  {-# INLINABLE get #-}+  get = do+    (rsa4, rsa3, rsa2, rsa1) <- Bin.get+    withSomeSing rsa4 $ \(sa4 :: Sing (a4 :: k4)) ->+      withSomeSing rsa3 $ \(sa3 :: Sing (a3 :: k3)) ->+        withSomeSing rsa2 $ \(sa2 :: Sing (a2 :: k2)) ->+          withSomeSing rsa1 $ \(sa1 :: Sing (a1 :: k1)) ->+            case dict4 sa4 sa3 sa2 sa1 :: Dict (Bin.Binary (f a4 a3 a2 a1)) of+              Dict -> do+                x :: f a4 a3 a2 a1 <- Bin.get+                pure (Some4 sa4 sa3 sa2 sa1 x)++--------------------------------------------------------------------------------++instance (Bin.Binary (l a1), Bin.Binary (r a1)) => Bin.Binary (S1 l r a1)+instance (Bin.Binary (l a2 a1), Bin.Binary (r a2 a1)) => Bin.Binary (S2 l r a2 a1)+instance (Bin.Binary (l a3 a2 a1), Bin.Binary (r a3 a2 a1)) => Bin.Binary (S3 l r a3 a2 a1)+instance (Bin.Binary (l a4 a3 a2 a1), Bin.Binary (r a4 a3 a2 a1)) => Bin.Binary (S4 l r a4 a3 a2 a1)++--------------------------------------------------------------------------------++instance (Bin.Binary (l a1), Bin.Binary (r a1)) => Bin.Binary (P1 l r a1)+instance (Bin.Binary (l a2 a1), Bin.Binary (r a2 a1)) => Bin.Binary (P2 l r a2 a1)+instance (Bin.Binary (l a3 a2 a1), Bin.Binary (r a3 a2 a1)) => Bin.Binary (P3 l r a3 a2 a1)+instance (Bin.Binary (l a4 a3 a2 a1), Bin.Binary (r a4 a3 a2 a1)) => Bin.Binary (P4 l r a4 a3 a2 a1)
+ lib/Exinst/DeepSeq.hs view
@@ -0,0 +1,78 @@+{-# LANGUAGE BangPatterns #-}+{-# LANGUAGE DataKinds #-}+{-# LANGUAGE FlexibleContexts #-}+{-# LANGUAGE PolyKinds #-}+{-# LANGUAGE ScopedTypeVariables #-}+{-# LANGUAGE UndecidableInstances #-}++{-# OPTIONS_GHC -fno-warn-orphans #-}++-- | This module exports 'NFData' instances for 'Some1', 'Some2', 'Some3' and+-- 'Some4' from "Exinst", provided situable 'Dict1', 'Dict2', 'Dict3'+-- and 'Dict4' instances are available.+--+-- See the README file in the @exinst@ package for more general documentation:+-- https://hackage.haskell.org/package/exinst#readme+module Exinst.DeepSeq () where++import Control.DeepSeq (NFData(rnf))+import Data.Constraint+import Data.Kind (Type)+import Prelude++import Exinst.Internal+import Exinst.Internal.Sum+import Exinst.Internal.Product++--------------------------------------------------------------------------------++instance forall k1 (f :: k1 -> Type).+  ( Dict1 NFData f+  ) => NFData (Some1 f) where+  {-# INLINABLE rnf #-}+  rnf = \(!some1x) ->+    withSome1Sing some1x $ \ !sa1 !(x :: f a1) ->+       case dict1 sa1 :: Dict (NFData (f a1)) of+          Dict -> rnf x `seq` ()++instance forall k2 k1 (f :: k2 -> k1 -> Type).+  ( Dict2 NFData f+  ) => NFData (Some2 f) where+  {-# INLINABLE rnf #-}+  rnf = \(!some2x) ->+    withSome2Sing some2x $ \ !sa2 !sa1 !(x :: f a2 a1) ->+       case dict2 sa2 sa1 :: Dict (NFData (f a2 a1)) of+          Dict -> rnf x `seq` ()++instance forall k3 k2 k1 (f :: k3 -> k2 -> k1 -> Type).+  ( Dict3 NFData f+  ) => NFData (Some3 f) where+  {-# INLINABLE rnf #-}+  rnf = \(!some3x) ->+    withSome3Sing some3x $ \ !sa3 !sa2 !sa1 !(x :: f a3 a2 a1) ->+       case dict3 sa3 sa2 sa1 :: Dict (NFData (f a3 a2 a1)) of+          Dict -> rnf x `seq` ()++instance forall k4 k3 k2 k1 (f :: k4 -> k3 -> k2 -> k1 -> Type).+  ( Dict4 NFData f+  ) => NFData (Some4 f) where+  {-# INLINABLE rnf #-}+  rnf = \(!some4x) ->+    withSome4Sing some4x $ \ !(sa4) !sa3 !sa2 !sa1 !(x :: f a4 a3 a2 a1) ->+       case dict4 sa4 sa3 sa2 sa1 :: Dict (NFData (f a4 a3 a2 a1)) of+          Dict -> rnf x `seq` ()++--------------------------------------------------------------------------------++instance (NFData (l a1), NFData (r a1)) => NFData (S1 l r a1)+instance (NFData (l a2 a1), NFData (r a2 a1)) => NFData (S2 l r a2 a1)+instance (NFData (l a3 a2 a1), NFData (r a3 a2 a1)) => NFData (S3 l r a3 a2 a1)+instance (NFData (l a4 a3 a2 a1), NFData (r a4 a3 a2 a1)) => NFData (S4 l r a4 a3 a2 a1)++--------------------------------------------------------------------------------++instance (NFData (l a1), NFData (r a1)) => NFData (P1 l r a1)+instance (NFData (l a2 a1), NFData (r a2 a1)) => NFData (P2 l r a2 a1)+instance (NFData (l a3 a2 a1), NFData (r a3 a2 a1)) => NFData (P3 l r a3 a2 a1)+instance (NFData (l a4 a3 a2 a1), NFData (r a4 a3 a2 a1)) => NFData (P4 l r a4 a3 a2 a1)+
+ lib/Exinst/Hashable.hs view
@@ -0,0 +1,123 @@+{-# LANGUAGE DataKinds #-}+{-# LANGUAGE FlexibleContexts #-}+{-# LANGUAGE PolyKinds #-}+{-# LANGUAGE ScopedTypeVariables #-}+{-# LANGUAGE TypeInType #-}+{-# LANGUAGE UndecidableInstances #-}++{-# OPTIONS_GHC -fno-warn-orphans #-}++-- | This module exports 'Hashable' instances for 'Some1', 'Some2', 'Some3' and+-- 'Some4' from "Exinst", provided situable 'Dict1', 'Dict2', 'Dict3'+-- and 'Dict4' instances are available.+--+-- See the README file in the @exinst@ package for more general documentation:+-- https://hackage.haskell.org/package/exinst#readme+module Exinst.Hashable () where++import Data.Hashable (Hashable(hashWithSalt))+import Data.Constraint+import Data.Kind (Type)+import Data.Singletons+import Prelude++import Exinst.Internal+import Exinst.Internal.Sum+import Exinst.Internal.Product++--------------------------------------------------------------------------------++-- | Some salt we add to hashes calculated in this module.+salt0 :: Int+salt0 = 6700417++--------------------------------------------------------------------------------++instance forall k1 (f :: k1 -> Type)+  . ( SingKind k1+    , Hashable (Demote k1)+    , Dict1 Hashable f+    , Eq (Some1 f)+    ) => Hashable (Some1 f)+  where+    {-# INLINABLE hashWithSalt #-}+    hashWithSalt salt some1x = withSome1Sing some1x $ \sa1 (x :: f a1) ->+       case dict1 sa1 :: Dict (Hashable (f a1)) of+          Dict -> salt `hashWithSalt` salt0+                       `hashWithSalt` fromSing sa1+                       `hashWithSalt` x++instance forall k2 k1 (f :: k2 -> k1 -> Type)+  . ( SingKind k2+    , SingKind k1+    , Hashable (Demote k2)+    , Hashable (Demote k1)+    , Dict2 Hashable f+    , Eq (Some2 f)+    ) => Hashable (Some2 f)+  where+    {-# INLINABLE hashWithSalt #-}+    hashWithSalt salt some2x = withSome2Sing some2x $ \sa2 sa1 (x :: f a2 a1) ->+       case dict2 sa2 sa1 :: Dict (Hashable (f a2 a1)) of+          Dict -> salt `hashWithSalt` salt0+                       `hashWithSalt` fromSing sa2+                       `hashWithSalt` fromSing sa1+                       `hashWithSalt` x++instance forall k3 k2 k1 (f :: k3 -> k2 -> k1 -> Type)+  . ( SingKind k3+    , SingKind k2+    , SingKind k1+    , Hashable (Demote k3)+    , Hashable (Demote k2)+    , Hashable (Demote k1)+    , Dict3 Hashable f+    , Eq (Some3 f)+    ) => Hashable (Some3 f)+  where+    {-# INLINABLE hashWithSalt #-}+    hashWithSalt salt some3x = withSome3Sing some3x $ \sa3 sa2 sa1 (x :: f a3 a2 a1) ->+       case dict3 sa3 sa2 sa1 :: Dict (Hashable (f a3 a2 a1)) of+          Dict -> salt `hashWithSalt` salt0+                       `hashWithSalt` fromSing sa3+                       `hashWithSalt` fromSing sa2+                       `hashWithSalt` fromSing sa1+                       `hashWithSalt` x++instance forall k4 k3 k2 k1 (f :: k4 -> k3 -> k2 -> k1 -> Type)+  . ( SingKind k4+    , SingKind k3+    , SingKind k2+    , SingKind k1+    , Hashable (Demote k4)+    , Hashable (Demote k3)+    , Hashable (Demote k2)+    , Hashable (Demote k1)+    , Eq (Some4 f)+    , Dict4 Hashable f+    ) => Hashable (Some4 f)+  where+    {-# INLINABLE hashWithSalt #-}+    hashWithSalt salt some4x = withSome4Sing some4x $ \sa4 sa3 sa2 sa1 (x :: f a4 a3 a2 a1) ->+       case dict4 sa4 sa3 sa2 sa1 :: Dict (Hashable (f a4 a3 a2 a1)) of+          Dict -> salt `hashWithSalt` salt0+                       `hashWithSalt` fromSing sa4+                       `hashWithSalt` fromSing sa3+                       `hashWithSalt` fromSing sa2+                       `hashWithSalt` fromSing sa1+                       `hashWithSalt` x++--------------------------------------------------------------------------------++instance (Hashable (l a1), Hashable (r a1)) => Hashable (S1 l r a1)+instance (Hashable (l a2 a1), Hashable (r a2 a1)) => Hashable (S2 l r a2 a1)+instance (Hashable (l a3 a2 a1), Hashable (r a3 a2 a1)) => Hashable (S3 l r a3 a2 a1)+instance (Hashable (l a4 a3 a2 a1), Hashable (r a4 a3 a2 a1)) => Hashable (S4 l r a4 a3 a2 a1)++--------------------------------------------------------------------------------++instance (Hashable (l a1), Hashable (r a1)) => Hashable (P1 l r a1)+instance (Hashable (l a2 a1), Hashable (r a2 a1)) => Hashable (P2 l r a2 a1)+instance (Hashable (l a3 a2 a1), Hashable (r a3 a2 a1)) => Hashable (P3 l r a3 a2 a1)+instance (Hashable (l a4 a3 a2 a1), Hashable (r a4 a3 a2 a1)) => Hashable (P4 l r a4 a3 a2 a1)+
+ lib/Exinst/Internal.hs view
@@ -0,0 +1,446 @@+{-# LANGUAGE DataKinds #-}+{-# LANGUAGE ExistentialQuantification #-}+{-# LANGUAGE FlexibleContexts #-}+{-# LANGUAGE MultiParamTypeClasses #-}+{-# LANGUAGE PolyKinds #-}+{-# LANGUAGE RankNTypes #-}+{-# LANGUAGE ScopedTypeVariables #-}+{-# LANGUAGE TypeFamilies #-}+{-# LANGUAGE TypeInType #-}+++module Exinst.Internal+ ( -- * 1 type index+   Some1(Some1)+ , some1+ , fromSome1+ , _Some1+ , withSome1+ , withSome1Sing+ , some1SingRep+ , same1+ , Dict1(dict1)++   -- * 2 type indexes+ , Some2(Some2)+ , some2+ , fromSome2+ , _Some2+ , withSome2+ , withSome2Sing+ , some2SingRep+ , same2+ , Dict2(dict2)++   -- * 3 type indexes+ , Some3(Some3)+ , some3+ , fromSome3+ , _Some3+ , withSome3+ , withSome3Sing+ , some3SingRep+ , same3+ , Dict3(dict3)++   -- * 4 type indexes+ , Some4(Some4)+ , some4+ , fromSome4+ , _Some4+ , withSome4+ , withSome4Sing+ , some4SingRep+ , same4+ , Dict4(dict4)++   -- * Miscellaneous+ , Dict0(dict0)+ ) where++import Data.Constraint+import Data.Kind (Type)+import Data.Profunctor (dimap, Choice(right'))+import Data.Singletons+import Data.Singletons.Decide+import Prelude++--------------------------------------------------------------------------------++data Some1 (f1 :: k1 -> Type) = forall a1.+  Some1 !(Sing a1) !(f1 a1)++data Some2 (f2 :: k2 -> k1 -> Type) = forall a2 a1.+  Some2 !(Sing a2) !(Sing a1) !(f2 a2 a1)++data Some3 (f3 :: k3 -> k2 -> k1 -> Type) = forall a3 a2 a1.+  Some3 !(Sing a3) !(Sing a2) !(Sing a1) !(f3 a3 a2 a1)++data Some4 (f4 :: k4 -> k3 -> k2 -> k1 -> Type) = forall a4 a3 a2 a1.+  Some4 !(Sing a4) !(Sing a3) !(Sing a2) !(Sing a1) !(f4 a4 a3 a2 a1)++--------------------------------------------------------------------------------++some1+  :: forall k1 (f1 :: k1 -> Type) a1+  .  SingI a1+  => f1 a1+  -> Some1 f1 -- ^+some1 = Some1 (sing :: Sing a1)+{-# INLINE some1 #-}++some2+  :: forall k2 k1 (f2 :: k2 -> k1 -> Type) a2 a1+  .  (SingI a2, SingI a1)+  => f2 a2 a1+  -> Some2 f2 -- ^+some2 = Some2 (sing :: Sing a2) (sing :: Sing a1)+{-# INLINE some2 #-}++some3+  :: forall k3 k2 k1 (f3 :: k3 -> k2 -> k1 -> Type) a3 a2 a1+  .  (SingI a3, SingI a2, SingI a1)+  => f3 a3 a2 a1+  -> Some3 f3 -- ^+some3 = Some3 (sing :: Sing a3) (sing :: Sing a2) (sing :: Sing a1)+{-# INLINE some3 #-}++some4+  :: forall k4 k3 k2 k1 (f4 :: k4 -> k3 -> k2 -> k1 -> Type) a4 a3 a2 a1+  .  (SingI a4, SingI a3, SingI a2, SingI a1)+  => f4 a4 a3 a2 a1+  -> Some4 f4 -- ^+some4 = Some4 (sing :: Sing a4) (sing :: Sing a3)+              (sing :: Sing a2) (sing :: Sing a1)+{-# INLINE some4 #-}++--------------------------------------------------------------------------------++withSome1+  :: forall k1 (f1 :: k1 -> Type) (r :: Type)+   . Some1 f1+  -> (forall a1. SingI a1 => f1 a1 -> r)+  -> r -- ^+withSome1 s1 g = withSome1Sing s1 (\_ -> g)+{-# INLINABLE withSome1 #-}++withSome2+  :: forall k2 k1 (f2 :: k2 -> k1 -> Type) (r :: Type)+  .  Some2 f2+  -> (forall a2 a1. (SingI a2, SingI a1) => f2 a2 a1 -> r)+  -> r -- ^+withSome2 s2 g = withSome2Sing s2 (\_ _ -> g)+{-# INLINABLE withSome2 #-}++withSome3+  :: forall k3 k2 k1 (f3 :: k3 -> k2 -> k1 -> Type) (r :: Type)+  .  Some3 f3+  -> (forall a3 a2 a1. (SingI a3, SingI a2, SingI a1) => f3 a3 a2 a1 -> r)+  -> r -- ^+withSome3 s3 g = withSome3Sing s3 (\_ _ _ -> g)+{-# INLINABLE withSome3 #-}++withSome4+  :: forall k4 k3 k2 k1 (f4 :: k4 -> k3 -> k2 -> k1 -> Type) (r :: Type)+  .  Some4 f4+  -> (forall a4 a3 a2 a1+        .  (SingI a4, SingI a3, SingI a2, SingI a1)+        => f4 a4 a3 a2 a1 -> r)+  -> r -- ^+withSome4 s4 g = withSome4Sing s4 (\_ _ _ _ -> g)+{-# INLINABLE withSome4 #-}++--------------------------------------------------------------------------------++-- | Like 'withSome1', but takes an explicit 'Sing' besides the 'SingI' instance.+withSome1Sing+  :: forall k1 (f1 :: k1 -> Type) (r :: Type)+   . Some1 f1+  -> (forall a1. (SingI a1) => Sing a1 -> f1 a1 -> r)+  -> r -- ^+withSome1Sing (Some1 sa1 x) g = withSingI sa1 (g sa1 x)+{-# INLINABLE withSome1Sing #-}++-- | Like 'withSome2', but takes explicit 'Sing's besides the 'SingI' instances.+withSome2Sing+  :: forall k2 k1 (f2 :: k2 -> k1 -> Type) (r :: Type)+  .  Some2 f2+  -> (forall a2 a1. (SingI a2, SingI a1) => Sing a2 -> Sing a1 -> f2 a2 a1 -> r)+  -> r -- ^+withSome2Sing (Some2 sa2 sa1 x) g = withSingI sa2 (withSingI sa1 (g sa2 sa1 x))+{-# INLINABLE withSome2Sing #-}++-- | Like 'withSome3', but takes explicit 'Sing's besides the 'SingI' instances.+withSome3Sing+  :: forall k3 k2 k1 (f3 :: k3 -> k2 -> k1 -> Type) (r :: Type)+  .  Some3 f3+  -> (forall a3 a2 a1+         .  (SingI a3, SingI a2, SingI a1)+         => Sing a3 -> Sing a2 -> Sing a1 -> f3 a3 a2 a1 -> r)+  -> r -- ^+withSome3Sing (Some3 sa3 sa2 sa1 x) g =+  withSingI sa3 (withSingI sa2 (withSingI sa1 (g sa3 sa2 sa1 x)))+{-# INLINABLE withSome3Sing #-}++-- | Like 'withSome4', but takes explicit 'Sing's besides the 'SingI' instances.+withSome4Sing+  :: forall k4 k3 k2 k1 (f4 :: k4 -> k3 -> k2 -> k1 -> Type) (r :: Type)+  .  Some4 f4+  -> (forall a4 a3 a2 a1+        .  (SingI a4, SingI a3, SingI a2, SingI a1)+        => Sing a4 -> Sing a3 -> Sing a2 -> Sing a1 -> f4 a4 a3 a2 a1 -> r)+  -> r -- ^+withSome4Sing (Some4 sa4 sa3 sa2 sa1 x) g =+  withSingI sa4 (withSingI sa3 (withSingI sa2 (withSingI sa1+     (g sa4 sa3 sa2 sa1 x))))+{-# INLINABLE withSome4Sing #-}++--------------------------------------------------------------------------------++fromSome1+   :: forall k1 (f1 :: k1 -> Type) a1+    . (SingI a1, SDecide k1)+   => Some1 f1+   -> Maybe (f1 a1) -- ^+fromSome1 = \(Some1 sa1' x) -> do+   Refl <- decideEquality sa1' (sing :: Sing a1)+   return x+{-# INLINABLE fromSome1 #-}++fromSome2+   :: forall k2 k1 (f2 :: k2 -> k1 -> Type) a2 a1+    . ( SingI a2, SDecide k2+      , SingI a1, SDecide k1 )+   => Some2 f2+   -> Maybe (f2 a2 a1) -- ^+fromSome2 = \(Some2 sa2' sa1' x) -> do+   Refl <- decideEquality sa2' (sing :: Sing a2)+   Refl <- decideEquality sa1' (sing :: Sing a1)+   return x+{-# INLINABLE fromSome2 #-}++fromSome3+   :: forall k3 k2 k1 (f3 :: k3 -> k2 -> k1 -> Type) a3 a2 a1+    . ( SingI a3, SDecide k3+      , SingI a2, SDecide k2+      , SingI a1, SDecide k1 )+   => Some3 f3+   -> Maybe (f3 a3 a2 a1) -- ^+fromSome3 = \(Some3 sa3' sa2' sa1' x) -> do+   Refl <- decideEquality sa3' (sing :: Sing a3)+   Refl <- decideEquality sa2' (sing :: Sing a2)+   Refl <- decideEquality sa1' (sing :: Sing a1)+   return x+{-# INLINABLE fromSome3 #-}++fromSome4+   :: forall k4 k3 k2 k1 (f4 :: k4 -> k3 -> k2 -> k1 -> Type) a4 a3 a2 a1+    . ( SingI a4, SDecide k4+      , SingI a3, SDecide k3+      , SingI a2, SDecide k2+      , SingI a1, SDecide k1 )+   => Some4 f4+   -> Maybe (f4 a4 a3 a2 a1) -- ^+fromSome4 = \(Some4 sa4' sa3' sa2' sa1' x) -> do+   Refl <- decideEquality sa4' (sing :: Sing a4)+   Refl <- decideEquality sa3' (sing :: Sing a3)+   Refl <- decideEquality sa2' (sing :: Sing a2)+   Refl <- decideEquality sa1' (sing :: Sing a1)+   return x+{-# INLINABLE fromSome4 #-}++--------------------------------------------------------------------------------++-- A @lens@-compatible 'Prism'' for constructing and deconstructing a 'Some1'.+_Some1+  :: forall k1 (f1 :: k1 -> Type) a1+  .  (SingI a1, SDecide k1)+  => Prism' (Some1 f1) (f1 a1)+_Some1 = prism' some1 fromSome1+{-# INLINE _Some1 #-}++-- A @lens@-compatible 'Prism'' for constructing and deconstructing a 'Some2'.+_Some2+  :: forall k2 k1 (f2 :: k2 -> k1 -> Type) a2 a1+  .  ( SingI a2, SDecide k2+     , SingI a1, SDecide k1 )+  => Prism' (Some2 f2) (f2 a2 a1)+_Some2 = prism' some2 fromSome2+{-# INLINE _Some2 #-}++-- A @lens@-compatible 'Prism'' for constructing and deconstructing a 'Some3'.+_Some3+  :: forall k3 k2 k1 (f3 :: k3 -> k2 -> k1 -> Type) a3 a2 a1+  .  ( SingI a3, SDecide k3+     , SingI a2, SDecide k2+     , SingI a1, SDecide k1 )+  => Prism' (Some3 f3) (f3 a3 a2 a1)+_Some3 = prism' some3 fromSome3+{-# INLINE _Some3 #-}++-- A @lens@-compatible 'Prism'' for constructing and deconstructing a 'Some4'.+_Some4+  :: forall k4 k3 k2 k1 (f4 :: k4 -> k3 -> k2 -> k1 -> Type) a4 a3 a2 a1+  .  ( SingI a4, SDecide k4+     , SingI a3, SDecide k3+     , SingI a2, SDecide k2+     , SingI a1, SDecide k1 )+  => Prism' (Some4 f4) (f4 a4 a3 a2 a1)+_Some4 = prism' some4 fromSome4+{-# INLINE _Some4 #-}++--------------------------------------------------------------------------------++some1SingRep+  :: SingKind k1+  => Some1 (f1 :: k1 -> Type)+  -> Demote k1 -- ^+some1SingRep = \(Some1 sa1 _) -> fromSing sa1+{-# INLINE some1SingRep #-}++some2SingRep+  :: (SingKind k2, SingKind k1)+  => Some2 (f2 :: k2 -> k1 -> Type)+  -> (Demote k2, Demote k1) -- ^+some2SingRep = \(Some2 sa2 sa1 _) -> (fromSing sa2, fromSing sa1)+{-# INLINE some2SingRep #-}++some3SingRep+  :: (SingKind k3, SingKind k2, SingKind k1)+  => Some3 (f3 :: k3 -> k2 -> k1 -> Type)+  -> (Demote k3, Demote k2, Demote k1) -- ^+some3SingRep = \(Some3 sa3 sa2 sa1 _) ->+  (fromSing sa3, fromSing sa2, fromSing sa1)+{-# INLINE some3SingRep #-}++some4SingRep+  :: (SingKind k4, SingKind k3, SingKind k2, SingKind k1)+  => Some4 (f4 :: k4 -> k3 -> k2 -> k1 -> Type)+  -> (Demote k4, Demote k3, Demote k2, Demote k1) -- ^+some4SingRep = \(Some4 sa4 sa3 sa2 sa1 _) ->+  (fromSing sa4, fromSing sa3, fromSing sa2, fromSing sa1)+{-# INLINE some4SingRep #-}++--------------------------------------------------------------------------------++-- | @'same1' x a b@ applies @x@ to the contents of @a@ and @b@ if their type+-- indexes are equal.+--+-- Hint: @'same1' ('some1' . 'Exinst.P1') :: 'Some1' f -> 'Some1' g -> 'Some1' ('Exinst.P1' f g)@+{-# INLINABLE same1 #-}+same1+  :: forall k1 f g x+  .  SDecide k1+  => (forall a1. SingI a1 => f a1 -> g a1 -> x)+  -> Some1 (f :: k1 -> Type)+  -> Some1 (g :: k1 -> Type)+  -> Maybe x  -- ^+same1 z = \s1f s1g ->+  withSome1Sing s1f $ \sa1 f ->+    withSome1Sing s1g $ \sa1' g -> do+       Refl <- decideEquality sa1 sa1'+       pure (z f g)++-- | @'same2' x a b@ applies @x@ to the contents of @a@ and @b@ if their type+-- indexes are equal.+--+-- Hint: @'same2' ('some2' . 'Exinst.P2') :: 'Some2' f -> 'Some2' g -> 'Some2' ('Exinst.P2' f g)@+{-# INLINABLE same2 #-}+same2+  :: forall k2 k1 f g x+  .  (SDecide k2, SDecide k1)+  => (forall a2 a1. SingI a1 => f a2 a1 -> g a2 a1 -> x)+  -> Some2 (f :: k2 -> k1 -> Type)+  -> Some2 (g :: k2 -> k1 -> Type)+  -> Maybe x  -- ^+same2 z = \s2l s2g ->+  withSome2Sing s2l $ \sa2 sa1 f ->+    withSome2Sing s2g $ \sa2' sa1' g -> do+       Refl <- decideEquality sa2 sa2'+       Refl <- decideEquality sa1 sa1'+       pure (z f g)++-- | @'same3' x a b@ applies @x@ to the contents of @a@ and @b@ if their type+-- indexes are equal.+--+-- Hint: @'same3' ('some3' . 'Exinst.P3') :: 'Some3' f -> 'Some3' g -> 'Some3' ('Exinst.P3' f g)@+{-# INLINABLE same3 #-}+same3+  :: forall k3 k2 k1 f g x+  .  (SDecide k3, SDecide k2, SDecide k1)+  => (forall a3 a2 a1. (SingI a3, SingI a2, SingI a1)+        => f a3 a2 a1 -> g a3 a2 a1 -> x)+  -> Some3 (f :: k3 -> k2 -> k1 -> Type)+  -> Some3 (g :: k3 -> k2 -> k1 -> Type)+  -> Maybe x  -- ^+same3 z = \s3l s3g ->+  withSome3Sing s3l $ \sa3 sa2 sa1 f ->+    withSome3Sing s3g $ \sa3' sa2' sa1' g -> do+       Refl <- decideEquality sa3 sa3'+       Refl <- decideEquality sa2 sa2'+       Refl <- decideEquality sa1 sa1'+       pure (z f g)++-- | @'same4' x a b@ applies @x@ to the contents of @a@ and @b@ if their type+-- indexes are equal.+--+-- Hint: @'same4' ('some4' . 'Exinst.P4') :: 'Some4' f -> 'Some4' g -> 'Some4' ('Exinst.P4' f g)@+{-# INLINABLE same4 #-}+same4+  :: forall k4 k3 k2 k1 f g x+  .  (SDecide k4, SDecide k3, SDecide k2, SDecide k1)+  => (forall a4 a3 a2 a1. (SingI a4, SingI a3, SingI a2, SingI a1)+        => f a4 a3 a2 a1 -> g a4 a3 a2 a1 -> x)+  -> Some4 (f :: k4 -> k3 -> k2 -> k1 -> Type)+  -> Some4 (g :: k4 -> k3 -> k2 -> k1 -> Type)+  -> Maybe x  -- ^+same4 z = \s4l s4g ->+  withSome4Sing s4l $ \sa4 sa3 sa2 sa1 f ->+    withSome4Sing s4g $ \sa4' sa3' sa2' sa1' g -> do+       Refl <- decideEquality sa4 sa4'+       Refl <- decideEquality sa3 sa3'+       Refl <- decideEquality sa2 sa2'+       Refl <- decideEquality sa1 sa1'+       pure (z f g)++--------------------------------------------------------------------------------++-- | 'Dict0' is a bit different from 'Dict1', 'Dict2', etc. in that it looks up+-- an instance for the singleton type itself, and not for some other type+-- indexed by said singleton type.+class Dict0 (c :: k0 -> Constraint) where+  -- | Runtime lookup of the @c a0@ instance.+  dict0 :: Sing a0 -> Dict (c a0)++class Dict1 (c :: k0 -> Constraint) (f1 :: k1 -> k0) where+  -- | Runtime lookup of the @c (f1 a1)@ instance.+  dict1 :: Sing a1 -> Dict (c (f1 a1))++class Dict2 (c :: k0 -> Constraint) (f2 :: k2 -> k1 -> k0) where+  -- Runtime lookup of the @c (f2 a2 a1)@ instance.+  dict2 :: Sing a2 -> Sing a1 -> Dict (c (f2 a2 a1))++class Dict3 (c :: k0 -> Constraint) (f3 :: k3 -> k2 -> k1 -> k0) where+  -- Runtime lookup of the @c (f3 a3 a2 a1)@ instance.+  dict3 :: Sing a3 -> Sing a2 -> Sing a1 -> Dict (c (f3 a3 a2 a1))++class Dict4 (c :: k0 -> Constraint) (f4 :: k4 -> k3 -> k2 -> k1 -> k0) where+  -- Runtime lookup of the @c (f4 a4 a3 a2 a1)@ instance.+  dict4 :: Sing a4 -> Sing a3 -> Sing a2 -> Sing a1 -> Dict (c (f4 a4 a3 a2 a1))++--------------------------------------------------------------------------------+-- Miscelaneous @lens@-compatible stuff.++type Prism s t a b+  = forall p f. (Choice p, Applicative f) => p a (f b) -> p s (f t)++type Prism' s a = Prism s s a a++prism :: (b -> t) -> (s -> Either t a) -> Prism s t a b+prism bt seta = dimap seta (either pure (fmap bt)) . right'+{-# INLINE prism #-}++prism' :: (b -> s) -> (s -> Maybe a) -> Prism s s a b+prism' bs sma = prism bs (\s -> maybe (Left s) Right (sma s))+{-# INLINE prism' #-}+
+ lib/Exinst/Internal/Product.hs view
@@ -0,0 +1,41 @@+{-# LANGUAGE DeriveGeneric #-}+{-# LANGUAGE PolyKinds #-}++module Exinst.Internal.Product+ ( P1(P1)+ , P2(P2)+ , P3(P3)+ , P4(P4)+ ) where++import GHC.Generics (Generic)++--------------------------------------------------------------------------------+-- Products++-- | Like 'Data.Functor.Product.Product' from "Data.Functor.Product", but+-- only intended to be used with kinds other than 'Type'.+--+-- This type is particularly useful when used in combination with 'Exinst.Some1'+-- as @'Exinst.Some1' ('P1' l r)@, so as to ensure that @l@ and @r@ are indexed+-- by the same type. Moreover, 'P1' already supports many common instances from+-- @base@, @hashable@, @deepseq@, @aeson@, @bytes@, @cereal@, @binary@, and+-- @quickcheck@ out of the box, so you can benefit from them as well.+data P1 l r (a1 :: k1)+  = P1 (l a1) (r a1)+  deriving (Eq, Show, Read, Ord, Generic)++-- | Like 'P1', but for @l@ and @r@ taking two type indexes.+data P2 l r (a2 :: k2) (a1 :: k1)+  = P2 (l a2 a1) (r a2 a1)+  deriving (Eq, Show, Read, Ord, Generic)++-- | Like 'P1', but for @l@ and @r@ taking three type indexes.+data P3 l r (a3 :: k3) (a2 :: k2) (a1 :: k1)+  = P3 (l a3 a2 a1) (r a3 a2 a1)+  deriving (Eq, Show, Read, Ord, Generic)++-- | Like 'P1', but for @l@ and @r@ taking four type indexes.+data P4 l r (a4 :: k4) (a3 :: k3) (a2 :: k2) (a1 :: k1)+  = P4 (l a4 a3 a2 a1) (r a4 a3 a2 a1)+  deriving (Eq, Show, Read, Ord, Generic)
+ lib/Exinst/Internal/Sum.hs view
@@ -0,0 +1,42 @@+{-# LANGUAGE DeriveGeneric #-}+{-# LANGUAGE PolyKinds #-}++module Exinst.Internal.Sum+ ( S1(S1L,S1R)+ , S2(S2L,S2R)+ , S3(S3L,S3R)+ , S4(S4L,S4R)+ ) where++import GHC.Generics (Generic)++--------------------------------------------------------------------------------+-- Sums++-- | Like 'Data.Functor.Sum.Sum' from "Data.Functor.Sum", but+-- only intended to be used with kinds other than 'Type'.+--+-- This type is particularly useful when used in combination with 'Exinst.Some1'+-- as @'Exinst.Some1' ('S1' l r)@, so as to ensure that @l@ and @r@ are indexed+-- by the same type. Moreover, 'S1' already supports many common instances from+-- @base@, @hashable@, @deepseq@, @aeson@, @bytes@, @cereal@, @binary@, and+-- @quickcheck@ out of the box, so you can benefit from them as well.+data S1 l r (a1 :: k1)+  = S1L (l a1) | S1R (r a1)+  deriving (Eq, Show, Read, Ord, Generic)++-- | Like 'S1', but for @l@ and @r@ taking two type indexes.+data S2 l r (a2 :: k2) (a1 :: k1)+  = S2L (l a2 a1) | S2R (r a2 a1)+  deriving (Eq, Show, Read, Ord, Generic)++-- | Like 'S1', but for @l@ and @r@ taking three type indexes.+data S3 l r (a3 :: k3) (a2 :: k2) (a1 :: k1)+  = S3L (l a3 a2 a1) | S3R (r a3 a2 a1)+  deriving (Eq, Show, Read, Ord, Generic)++-- | Like 'S1', but for @l@ and @r@ taking four type indexes.+data S4 l r (a4 :: k4) (a3 :: k3) (a2 :: k2) (a1 :: k1)+  = S4L (l a4 a3 a2 a1) | S4R (r a4 a3 a2 a1)+  deriving (Eq, Show, Read, Ord, Generic)+
+ lib/Exinst/QuickCheck.hs view
@@ -0,0 +1,142 @@+{-# LANGUAGE FlexibleContexts #-}+{-# LANGUAGE ScopedTypeVariables #-}+{-# LANGUAGE TypeInType #-}+{-# LANGUAGE UndecidableInstances #-}++{-# OPTIONS_GHC -fno-warn-orphans #-}++-- | This module exports 'QC.arbitrary' instances for 'Exinst.Some1', 'Some2',+-- 'Some3' and 'Some4' from "Exinst", provided situable 'Dict1',+-- 'Dict2', 'Dict3' and 'Dict4' instances are available.+--+-- See the README file for more general documentation: https://hackage.haskell.org/package/exinst#readme+module Exinst.QuickCheck () where++import Data.Constraint+import Data.Kind (Type)+import Data.Singletons (SingKind, Sing, Demote, withSomeSing)+import qualified Test.QuickCheck as QC++import Exinst.Internal+import Exinst.Internal.Sum+import Exinst.Internal.Product++--------------------------------------------------------------------------------++instance+  forall k1 (f :: k1 -> Type).+  ( SingKind k1+  , QC.Arbitrary (Demote k1)+  , Dict1 QC.Arbitrary f+  ) => QC.Arbitrary (Some1 f) where+  arbitrary = do+    da1 <- QC.arbitrary+    withSomeSing da1 $ \(sa1 :: Sing (a1 :: k1)) ->+      case dict1 sa1 :: Dict (QC.Arbitrary (f a1)) of+        Dict -> Some1 sa1 <$> QC.arbitrary+  shrink = \s1x -> withSome1Sing s1x $ \sa1 (x :: f a1) ->+    case dict1 sa1 :: Dict (QC.Arbitrary (f a1)) of+      Dict -> Some1 sa1 <$> QC.shrink x++instance+  forall k2 k1 (f :: k2 -> k1 -> Type).+  ( SingKind k2+  , SingKind k1+  , QC.Arbitrary (Demote k2)+  , QC.Arbitrary (Demote k1)+  , Dict2 QC.Arbitrary f+  ) => QC.Arbitrary (Some2 f) where+  arbitrary = do+    da2 <- QC.arbitrary+    da1 <- QC.arbitrary+    withSomeSing da2 $ \(sa2 :: Sing (a2 :: k2)) ->+      withSomeSing da1 $ \(sa1 :: Sing (a1 :: k1)) ->+        case dict2 sa2 sa1 :: Dict (QC.Arbitrary (f a2 a1)) of+          Dict -> Some2 sa2 sa1 <$> QC.arbitrary+  shrink = \s2x -> withSome2Sing s2x $ \sa2 sa1 (x :: f a2 a1) ->+    case dict2 sa2 sa1 :: Dict (QC.Arbitrary (f a2 a1)) of+      Dict -> Some2 sa2 sa1 <$> QC.shrink x++instance+  forall k3 k2 k1 (f :: k3 -> k2 -> k1 -> Type).+  ( SingKind k3+  , SingKind k2+  , SingKind k1+  , QC.Arbitrary (Demote k3)+  , QC.Arbitrary (Demote k2)+  , QC.Arbitrary (Demote k1)+  , Dict3 QC.Arbitrary f+  ) => QC.Arbitrary (Some3 f) where+  arbitrary = do+    da3 <- QC.arbitrary+    da2 <- QC.arbitrary+    da1 <- QC.arbitrary+    withSomeSing da3 $ \(sa3 :: Sing (a3 :: k3)) ->+      withSomeSing da2 $ \(sa2 :: Sing (a2 :: k2)) ->+        withSomeSing da1 $ \(sa1 :: Sing (a1 :: k1)) ->+          case dict3 sa3 sa2 sa1 :: Dict (QC.Arbitrary (f a3 a2 a1)) of+            Dict -> Some3 sa3 sa2 sa1 <$> QC.arbitrary+  shrink = \s3x -> withSome3Sing s3x $ \sa3 sa2 sa1 (x :: f a3 a2 a1) ->+    case dict3 sa3 sa2 sa1 :: Dict (QC.Arbitrary (f a3 a2 a1)) of+      Dict -> Some3 sa3 sa2 sa1 <$> QC.shrink x++instance+  forall k4 k3 k2 k1 (f :: k4 -> k3 -> k2 -> k1 -> Type).+  ( SingKind k4+  , SingKind k3+  , SingKind k2+  , SingKind k1+  , QC.Arbitrary (Demote k4)+  , QC.Arbitrary (Demote k3)+  , QC.Arbitrary (Demote k2)+  , QC.Arbitrary (Demote k1)+  , Dict4 QC.Arbitrary f+  ) => QC.Arbitrary (Some4 f) where+  arbitrary = do+    da4 <- QC.arbitrary+    da3 <- QC.arbitrary+    da2 <- QC.arbitrary+    da1 <- QC.arbitrary+    withSomeSing da4 $ \(sa4 :: Sing (a4 :: k4)) ->+      withSomeSing da3 $ \(sa3 :: Sing (a3 :: k3)) ->+        withSomeSing da2 $ \(sa2 :: Sing (a2 :: k2)) ->+          withSomeSing da1 $ \(sa1 :: Sing (a1 :: k1)) ->+            case dict4 sa4 sa3 sa2 sa1 :: Dict (QC.Arbitrary (f a4 a3 a2 a1)) of+              Dict -> Some4 sa4 sa3 sa2 sa1 <$> QC.arbitrary+  shrink = \s3x -> withSome4Sing s3x $ \sa4 sa3 sa2 sa1 (x :: f a4 a3 a2 a1) ->+    case dict4 sa4 sa3 sa2 sa1 :: Dict (QC.Arbitrary (f a4 a3 a2 a1)) of+      Dict -> Some4 sa4 sa3 sa2 sa1 <$> QC.shrink x++--------------------------------------------------------------------------------++instance (QC.Arbitrary (l a1), QC.Arbitrary (r a1)) => QC.Arbitrary (S1 l r a1) where+  arbitrary = QC.oneof [ fmap S1L QC.arbitrary, fmap S1R QC.arbitrary ]+  shrink (S1L l) = S1L <$> QC.shrink l+  shrink (S1R r) = S1R <$> QC.shrink r+instance (QC.Arbitrary (l a2 a1), QC.Arbitrary (r a2 a1)) => QC.Arbitrary (S2 l r a2 a1) where+  arbitrary = QC.oneof [ fmap S2L QC.arbitrary, fmap S2R QC.arbitrary ]+  shrink (S2L l) = S2L <$> QC.shrink l+  shrink (S2R r) = S2R <$> QC.shrink r+instance (QC.Arbitrary (l a3 a2 a1), QC.Arbitrary (r a3 a2 a1)) => QC.Arbitrary (S3 l r a3 a2 a1) where+  arbitrary = QC.oneof [ fmap S3L QC.arbitrary, fmap S3R QC.arbitrary ]+  shrink (S3L l) = S3L <$> QC.shrink l+  shrink (S3R r) = S3R <$> QC.shrink r+instance (QC.Arbitrary (l a4 a3 a2 a1), QC.Arbitrary (r a4 a3 a2 a1)) => QC.Arbitrary (S4 l r a4 a3 a2 a1) where+  arbitrary = QC.oneof [ fmap S4L QC.arbitrary, fmap S4R QC.arbitrary ]+  shrink (S4L l) = S4L <$> QC.shrink l+  shrink (S4R r) = S4R <$> QC.shrink r++--------------------------------------------------------------------------------++instance (QC.Arbitrary (l a1), QC.Arbitrary (r a1)) => QC.Arbitrary (P1 l r a1) where+  arbitrary = P1 <$> QC.arbitrary <*> QC.arbitrary+  shrink (P1 x y) = P1 <$> QC.shrink x <*> QC.shrink y+instance (QC.Arbitrary (l a2 a1), QC.Arbitrary (r a2 a1)) => QC.Arbitrary (P2 l r a2 a1) where+  arbitrary = P2 <$> QC.arbitrary <*> QC.arbitrary+  shrink (P2 x y) = P2 <$> QC.shrink x <*> QC.shrink y+instance (QC.Arbitrary (l a3 a2 a1), QC.Arbitrary (r a3 a2 a1)) => QC.Arbitrary (P3 l r a3 a2 a1) where+  arbitrary = P3 <$> QC.arbitrary <*> QC.arbitrary+  shrink (P3 x y) = P3 <$> QC.shrink x <*> QC.shrink y+instance (QC.Arbitrary (l a4 a3 a2 a1), QC.Arbitrary (r a4 a3 a2 a1)) => QC.Arbitrary (P4 l r a4 a3 a2 a1) where+  arbitrary = P4 <$> QC.arbitrary <*> QC.arbitrary+  shrink (P4 x y) = P4 <$> QC.shrink x <*> QC.shrink y
− src/lib/Exinst/Instances/Base.hs 
@@ -1,285 +0,0 @@-{-# LANGUAGE ConstraintKinds #-}-{-# LANGUAGE DataKinds #-}-{-# LANGUAGE FlexibleInstances #-}-{-# LANGUAGE LambdaCase #-}-{-# LANGUAGE MultiParamTypeClasses #-}-{-# LANGUAGE PolyKinds #-}-{-# LANGUAGE ScopedTypeVariables #-}-{-# LANGUAGE TypeFamilies #-}-{-# LANGUAGE TypeInType #-}-{-# LANGUAGE UndecidableInstances #-}--{-# OPTIONS_GHC -fno-warn-orphans #-}---- | This module exports 'Show', 'Eq' and 'Ord' instances for 'Exinst.Some1',--- 'Exinst.Some2', 'Exinst.Some3' and 'Exinst.Some4' from "Exinst.Singletons", provided situable--- 'Dict1', 'Dict2', 'Dict3' and 'Dict4' instances are available.------ See the README file for more general documentation: https://hackage.haskell.org/package/exinst#readme-module Exinst.Instances.Base () where--import Data.Constraint-import Data.Kind (Type)-import Data.Singletons-import Data.Singletons.Prelude.Bool (Sing(STrue,SFalse))-import Data.Singletons.Decide-import Data.Type.Equality-import Exinst.Singletons-  hiding (Some1(..), Some2(..), Some3(..), Some4(..))-import qualified Exinst.Singletons as Exinst-import Prelude-------------------------------------------------------------------------------------- Internal wrappers used to avoid writing the string manipulation in 'Show'-data Some1'Show r1 x = Some1 r1 x deriving (Show)-data Some2'Show r2 r1 x = Some2 r2 r1 x deriving (Show)-data Some3'Show r3 r2 r1 x = Some3 r3 r2 r1 x deriving (Show)-data Some4'Show r4 r3 r2 r1 x = Some4 r4 r3 r2 r1 x deriving (Show)------------------------------------------------------------------------------------- Show--instance forall (f1 :: k1 -> Type)-  . ( SingKind k1-    , Show (DemoteRep k1)-    , Dict1 Show f1-    ) => Show (Exinst.Some1 f1)-  where-    {-# INLINABLE showsPrec #-}-    showsPrec n = \some1x -> withSome1Sing some1x $ \sa1 (x :: f1 a1) ->-       case dict1 sa1 :: Dict (Show (f1 a1)) of-          Dict -> showsPrec n (Some1 (fromSing sa1) x)--instance forall (f2 :: k2 -> k1 -> Type)-  . ( SingKind k2-    , SingKind k1-    , Show (DemoteRep k2)-    , Show (DemoteRep k1)-    , Dict2 Show f2-    ) => Show (Exinst.Some2 f2)-  where-    {-# INLINABLE showsPrec #-}-    showsPrec n = \some2x -> withSome2Sing some2x $ \sa2 sa1 (x :: f2 a2 a1) ->-       case dict2 sa2 sa1 :: Dict (Show (f2 a2 a1)) of-          Dict -> showsPrec n (Some2 (fromSing sa2) (fromSing sa1) x)--instance forall (f3 :: k3 -> k2 -> k1 -> Type)-  . ( SingKind k3-    , SingKind k2-    , SingKind k1-    , Show (DemoteRep k3)-    , Show (DemoteRep k2)-    , Show (DemoteRep k1)-    , Dict3 Show f3-    ) => Show (Exinst.Some3 f3)-  where-    {-# INLINABLE showsPrec #-}-    showsPrec n = \some3x -> withSome3Sing some3x $ \sa3 sa2 sa1 (x :: f3 a3 a2 a1) ->-       case dict3 sa3 sa2 sa1 :: Dict (Show (f3 a3 a2 a1)) of-          Dict -> showsPrec n (Some3 (fromSing sa3) (fromSing sa2) (fromSing sa1) x)--instance forall (f4 :: k4 -> k3 -> k2 -> k1 -> Type)-  . ( SingKind k4-    , SingKind k3-    , SingKind k2-    , SingKind k1-    , Show (DemoteRep k4)-    , Show (DemoteRep k3)-    , Show (DemoteRep k2)-    , Show (DemoteRep k1)-    , Dict4 Show f4-    ) => Show (Exinst.Some4 f4)-  where-    {-# INLINABLE showsPrec #-}-    showsPrec n = \some4x -> withSome4Sing some4x $ \sa4 sa3 sa2 sa1 (x :: f4 a4 a3 a2 a1) ->-       case dict4 sa4 sa3 sa2 sa1 :: Dict (Show (f4 a4 a3 a2 a1)) of-          Dict -> showsPrec n (Some4 (fromSing sa4) (fromSing sa3)-                                     (fromSing sa2) (fromSing sa1) x)------------------------------------------------------------------------------------- Read------------------------------------------------------------------------------------- Eq--instance forall (f1 :: k1 -> Type)-  . ( SDecide k1-    , Dict1 Eq f1-    ) => Eq (Exinst.Some1 f1)-  where-    {-# INLINABLE (==) #-}-    (==) = \som1x som1y ->-       withSome1Sing som1x $ \sa1x (x :: f1 a1x) ->-          withSome1Sing som1y $ \sa1y (y :: f1 a1y) ->-             maybe False id $ do-                Refl <- testEquality sa1x sa1y-                case dict1 sa1x :: Dict (Eq (f1 a1x)) of-                   Dict -> Just (x == y)--instance forall (f2 :: k2 -> k1 -> Type)-  . ( SDecide k2-    , SDecide k1-    , Dict2 Eq f2-    ) => Eq (Exinst.Some2 f2)-  where-    {-# INLINABLE (==) #-}-    (==) = \som2x som2y ->-       withSome2Sing som2x $ \sa2x sa1x (x :: f2 a2x a1x) ->-          withSome2Sing som2y $ \sa2y sa1y (y :: f2 a2y a1y) ->-             maybe False id $ do-                Refl <- testEquality sa2x sa2y-                Refl <- testEquality sa1x sa1y-                case dict2 sa2x sa1x :: Dict (Eq (f2 a2x a1x)) of-                   Dict -> Just (x == y)--instance forall (f3 :: k3 -> k2 -> k1 -> Type)-  . ( SDecide k3-    , SDecide k2-    , SDecide k1-    , Dict3 Eq f3-    ) => Eq (Exinst.Some3 f3)-  where-    {-# INLINABLE (==) #-}-    (==) = \som3x som3y ->-       withSome3Sing som3x $ \sa3x sa2x sa1x (x :: f3 a3x a2x a1x) ->-          withSome3Sing som3y $ \sa3y sa2y sa1y (y :: f3 a3y a2y a1y) ->-             maybe False id $ do-                Refl <- testEquality sa3x sa3y-                Refl <- testEquality sa2x sa2y-                Refl <- testEquality sa1x sa1y-                case dict3 sa3x sa2x sa1x :: Dict (Eq (f3 a3x a2x a1x)) of-                   Dict -> Just (x == y)--instance forall (f4 :: k4 -> k3 -> k2 -> k1 -> Type)-  . ( SDecide k4-    , SDecide k3-    , SDecide k2-    , SDecide k1-    , Dict4 Eq f4-    ) => Eq (Exinst.Some4 f4)-  where-    {-# INLINABLE (==) #-}-    (==) = \som4x som4y ->-       withSome4Sing som4x $ \sa4x sa3x sa2x sa1x (x :: f4 a4x a3x a2x a1x) ->-          withSome4Sing som4y $ \sa4y sa3y sa2y sa1y (y :: f4 a4y a3y a2y a1y) ->-             maybe False id $ do-                Refl <- testEquality sa4x sa4y-                Refl <- testEquality sa3x sa3y-                Refl <- testEquality sa2x sa2y-                Refl <- testEquality sa1x sa1y-                case dict4 sa4x sa3x sa2x sa1x :: Dict (Eq (f4 a4x a3x a2x a1x)) of-                   Dict -> Just (x == y)------------------------------------------------------------------------------------- Ord--instance forall (f1 :: k1 -> Type)-  . ( SingKind k1-    , SDecide k1-    , Ord (DemoteRep k1)-    , Dict1 Ord f1-    , Eq (Exinst.Some1 f1)-    ) => Ord (Exinst.Some1 f1)-  where-    {-# INLINABLE compare #-}-    compare = \som1x som1y ->-       withSome1Sing som1x $ \sa1x (x :: f1 a1x) ->-          withSome1Sing som1y $ \sa1y (y :: f1 a1y) ->-             let termCompare = compare (fromSing sa1x) (fromSing sa1y)-             in maybe termCompare id $ do-                  Refl <- testEquality sa1x sa1y-                  case dict1 sa1x :: Dict (Ord (f1 a1x)) of-                     Dict -> Just (compare x y)--instance forall (f2 :: k2 -> k1 -> Type)-  . ( SingKind k2-    , SingKind k1-    , SDecide k2-    , SDecide k1-    , Ord (DemoteRep k2)-    , Ord (DemoteRep k1)-    , Dict2 Ord f2-    , Eq (Exinst.Some2 f2)-    ) => Ord (Exinst.Some2 f2)-  where-    {-# INLINABLE compare #-}-    compare = \som2x som2y ->-       withSome2Sing som2x $ \sa2x sa1x (x :: f2 a2x a1x) ->-          withSome2Sing som2y $ \sa2y sa1y (y :: f2 a2y a1y) ->-             let termCompare = compare (fromSing sa2x, fromSing sa1x)-                                       (fromSing sa2y, fromSing sa1y)-             in maybe termCompare id $ do-                   Refl <- testEquality sa2x sa2y-                   Refl <- testEquality sa1x sa1y-                   case dict2 sa2x sa1x :: Dict (Ord (f2 a2x a1x)) of-                      Dict -> Just (compare x y)--instance forall (f3 :: k3 -> k2 -> k1 -> Type)-  . ( SingKind k3-    , SingKind k2-    , SingKind k1-    , SDecide k3-    , SDecide k2-    , SDecide k1-    , Ord (DemoteRep k3)-    , Ord (DemoteRep k2)-    , Ord (DemoteRep k1)-    , Dict3 Ord f3-    , Eq (Exinst.Some3 f3)-    ) => Ord (Exinst.Some3 f3)-  where-    {-# INLINABLE compare #-}-    compare = \som3x som3y ->-       withSome3Sing som3x $ \sa3x sa2x sa1x (x :: f3 a3x a2x a1x) ->-          withSome3Sing som3y $ \sa3y sa2y sa1y (y :: f3 a3y a2y a1y) ->-             let termCompare = compare-                   (fromSing sa3x, fromSing sa2x, fromSing sa1x)-                   (fromSing sa3y, fromSing sa2y, fromSing sa1y)-             in maybe termCompare id $ do-                  Refl <- testEquality sa3x sa3y-                  Refl <- testEquality sa2x sa2y-                  Refl <- testEquality sa1x sa1y-                  case dict3 sa3x sa2x sa1x :: Dict (Ord (f3 a3x a2x a1x)) of-                     Dict -> Just (compare x y)--instance forall (f4 :: k4 -> k3 -> k2 -> k1 -> Type)-  . ( SingKind k4-    , SingKind k3-    , SingKind k2-    , SingKind k1-    , SDecide k4-    , SDecide k3-    , SDecide k2-    , SDecide k1-    , Ord (DemoteRep k4)-    , Ord (DemoteRep k3)-    , Ord (DemoteRep k2)-    , Ord (DemoteRep k1)-    , Dict4 Ord f4-    , Eq (Exinst.Some4 f4)-    ) => Ord (Exinst.Some4 f4)-  where-    {-# INLINABLE compare #-}-    compare = \som4x som4y ->-       withSome4Sing som4x $ \sa4x sa3x sa2x sa1x (x :: f4 a4x a3x a2x a1x) ->-          withSome4Sing som4y $ \sa4y sa3y sa2y sa1y (y :: f4 a4y a3y a2y a1y) ->-             let termCompare = compare-                   (fromSing sa4x, fromSing sa3x, fromSing sa2x, fromSing sa1x)-                   (fromSing sa4y, fromSing sa3y, fromSing sa2y, fromSing sa1y)-             in maybe termCompare id $ do-                  Refl <- testEquality sa4x sa4y-                  Refl <- testEquality sa3x sa3y-                  Refl <- testEquality sa2x sa2y-                  Refl <- testEquality sa1x sa1y-                  case dict4 sa4x sa3x sa2x sa1x :: Dict (Ord (f4 a4x a3x a2x a1x)) of-                     Dict -> Just (compare x y)---------------------------------------------------------------------------------------------------------------------------------------------------------------------- Out of the box 'Dict1' instances for some @base@ types--instance (c (f 'True), c (f 'False)) => Dict1 c (f :: Bool -> k0) where-  dict1 = \case-    STrue -> Dict-    SFalse -> Dict
− src/lib/Exinst/Singletons.hs 
@@ -1,353 +0,0 @@-{-# LANGUAGE DataKinds #-}-{-# LANGUAGE ExistentialQuantification #-}-{-# LANGUAGE FlexibleContexts #-}-{-# LANGUAGE MultiParamTypeClasses #-}-{-# LANGUAGE PolyKinds #-}-{-# LANGUAGE RankNTypes #-}-{-# LANGUAGE ScopedTypeVariables #-}-{-# LANGUAGE TypeFamilies #-}-{-# LANGUAGE TypeInType #-}---- | See the README file for documentation: https://hackage.haskell.org/package/exinst#readme-module Exinst.Singletons- ( -- * 1 type index-   Some1(Some1)- , some1- , fromSome1- , _Some1- , withSome1- , withSome1Sing- , some1SingRep- , Dict1(dict1)--   -- * 2 type indexes- , Some2(Some2)- , some2- , fromSome2- , _Some2- , withSome2- , withSome2Sing- , some2SingRep- , Dict2(dict2)--   -- * 3 type indexes- , Some3(Some3)- , some3- , fromSome3- , _Some3- , withSome3- , withSome3Sing- , some3SingRep- , Dict3(dict3)--   -- * 4 type indexes- , Some4(Some4)- , some4- , fromSome4- , _Some4- , withSome4- , withSome4Sing- , some4SingRep- , Dict4(dict4)--   -- * Re-exports- , Dict(Dict)- ) where--import Data.Constraint-import Data.Kind (Type)-import Data.Profunctor (dimap, Choice(right'))-import Data.Singletons-import Data.Singletons.Decide-import Data.Type.Equality-import Prelude------------------------------------------------------------------------------------data Some1 (f1 :: k1 -> Type) = forall a1.-  Some1 !(Sing a1) !(f1 a1)--data Some2 (f2 :: k2 -> k1 -> Type) = forall a2 a1.-  Some2 !(Sing a2) !(Sing a1) !(f2 a2 a1)--data Some3 (f3 :: k3 -> k2 -> k1 -> Type) = forall a3 a2 a1.-  Some3 !(Sing a3) !(Sing a2) !(Sing a1) !(f3 a3 a2 a1)--data Some4 (f4 :: k4 -> k3 -> k2 -> k1 -> Type) = forall a4 a3 a2 a1.-  Some4 !(Sing a4) !(Sing a3) !(Sing a2) !(Sing a1) !(f4 a4 a3 a2 a1)------------------------------------------------------------------------------------some1-  :: forall (f1 :: k1 -> Type) a1-  .  SingI a1-  => f1 a1-  -> Some1 f1 -- ^-some1 = Some1 (sing :: Sing a1)-{-# INLINE some1 #-}--some2-  :: forall (f2 :: k2 -> k1 -> Type) a2 a1-  .  (SingI a2, SingI a1)-  => f2 a2 a1-  -> Some2 f2 -- ^-some2 = Some2 (sing :: Sing a2) (sing :: Sing a1)-{-# INLINE some2 #-}--some3-  :: forall (f3 :: k3 -> k2 -> k1 -> Type) a3 a2 a1-  .  (SingI a3, SingI a2, SingI a1)-  => f3 a3 a2 a1-  -> Some3 f3 -- ^-some3 = Some3 (sing :: Sing a3) (sing :: Sing a2) (sing :: Sing a1)-{-# INLINE some3 #-}--some4-  :: forall (f4 :: k4 -> k3 -> k2 -> k1 -> Type) a4 a3 a2 a1-  .  (SingI a4, SingI a3, SingI a2, SingI a1)-  => f4 a4 a3 a2 a1-  -> Some4 f4 -- ^-some4 = Some4 (sing :: Sing a4) (sing :: Sing a3)-              (sing :: Sing a2) (sing :: Sing a1)-{-# INLINE some4 #-}------------------------------------------------------------------------------------withSome1-  :: forall (f1 :: k1 -> Type) (r :: Type)-   . Some1 f1-  -> (forall a1. SingI a1 => f1 a1 -> r)-  -> r -- ^-withSome1 s1 g = withSome1Sing s1 (\_ -> g)-{-# INLINABLE withSome1 #-}--withSome2-  :: forall (f2 :: k2 -> k1 -> Type) (r :: Type)-  .  Some2 f2-  -> (forall a2 a1. (SingI a2, SingI a1) => f2 a2 a1 -> r)-  -> r -- ^-withSome2 s2 g = withSome2Sing s2 (\_ _ -> g)-{-# INLINABLE withSome2 #-}--withSome3-  :: forall (f3 :: k3 -> k2 -> k1 -> Type) (r :: Type)-  .  Some3 f3-  -> (forall a3 a2 a1. (SingI a3, SingI a2, SingI a1) => f3 a3 a2 a1 -> r)-  -> r -- ^-withSome3 s3 g = withSome3Sing s3 (\_ _ _ -> g)-{-# INLINABLE withSome3 #-}--withSome4-  :: forall (f4 :: k4 -> k3 -> k2 -> k1 -> Type) (r :: Type)-  .  Some4 f4-  -> (forall a4 a3 a2 a1-        .  (SingI a4, SingI a3, SingI a2, SingI a1)-        => f4 a4 a3 a2 a1 -> r)-  -> r -- ^-withSome4 s4 g = withSome4Sing s4 (\_ _ _ _ -> g)-{-# INLINABLE withSome4 #-}-------------------------------------------------------------------------------------- | Like 'withSome1', but takes an explicit 'Sing' besides the 'SingI' instance.-withSome1Sing-  :: forall (f1 :: k1 -> Type) (r :: Type)-   . Some1 f1-  -> (forall a1. (SingI a1) => Sing a1 -> f1 a1 -> r)-  -> r -- ^-withSome1Sing (Some1 sa1 x) g = withSingI sa1 (g sa1 x)-{-# INLINABLE withSome1Sing #-}---- | Like 'withSome2', but takes explicit 'Sing's besides the 'SingI' instances.-withSome2Sing-  :: forall (f2 :: k2 -> k1 -> Type) (r :: Type)-  .  Some2 f2-  -> (forall a2 a1. (SingI a2, SingI a1) => Sing a2 -> Sing a1 -> f2 a2 a1 -> r)-  -> r -- ^-withSome2Sing (Some2 sa2 sa1 x) g = withSingI sa2 (withSingI sa1 (g sa2 sa1 x))-{-# INLINABLE withSome2Sing #-}---- | Like 'withSome3', but takes explicit 'Sing's besides the 'SingI' instances.-withSome3Sing-  :: forall (f3 :: k3 -> k2 -> k1 -> Type) (r :: Type)-  .  Some3 f3-  -> (forall a3 a2 a1-         .  (SingI a3, SingI a2, SingI a1)-         => Sing a3 -> Sing a2 -> Sing a1 -> f3 a3 a2 a1 -> r)-  -> r -- ^-withSome3Sing (Some3 sa3 sa2 sa1 x) g =-  withSingI sa3 (withSingI sa2 (withSingI sa1 (g sa3 sa2 sa1 x)))-{-# INLINABLE withSome3Sing #-}---- | Like 'withSome4', but takes explicit 'Sing's besides the 'SingI' instances.-withSome4Sing-  :: forall (f4 :: k4 -> k3 -> k2 -> k1 -> Type) (r :: Type)-  .  Some4 f4-  -> (forall a4 a3 a2 a1-        .  (SingI a4, SingI a3, SingI a2, SingI a1)-        => Sing a4 -> Sing a3 -> Sing a2 -> Sing a1 -> f4 a4 a3 a2 a1 -> r)-  -> r -- ^-withSome4Sing (Some4 sa4 sa3 sa2 sa1 x) g =-  withSingI sa4 (withSingI sa3 (withSingI sa2 (withSingI sa1-     (g sa4 sa3 sa2 sa1 x))))-{-# INLINABLE withSome4Sing #-}------------------------------------------------------------------------------------fromSome1-   :: forall (f1 :: k1 -> Type) a1-    . (SingI a1, SDecide k1)-   => Some1 f1-   -> Maybe (f1 a1) -- ^-fromSome1 = \(Some1 sa1' x) -> do-   Refl <- testEquality sa1' (sing :: Sing a1)-   return x-{-# INLINABLE fromSome1 #-}--fromSome2-   :: forall (f2 :: k2 -> k1 -> Type) a2 a1-    . ( SingI a2, SDecide k2-      , SingI a1, SDecide k1 )-   => Some2 f2-   -> Maybe (f2 a2 a1) -- ^-fromSome2 = \(Some2 sa2' sa1' x) -> do-   Refl <- testEquality sa2' (sing :: Sing a2)-   Refl <- testEquality sa1' (sing :: Sing a1)-   return x-{-# INLINABLE fromSome2 #-}--fromSome3-   :: forall (f3 :: k3 -> k2 -> k1 -> Type) a3 a2 a1-    . ( SingI a3, SDecide k3-      , SingI a2, SDecide k2-      , SingI a1, SDecide k1 )-   => Some3 f3-   -> Maybe (f3 a3 a2 a1) -- ^-fromSome3 = \(Some3 sa3' sa2' sa1' x) -> do-   Refl <- testEquality sa3' (sing :: Sing a3)-   Refl <- testEquality sa2' (sing :: Sing a2)-   Refl <- testEquality sa1' (sing :: Sing a1)-   return x-{-# INLINABLE fromSome3 #-}--fromSome4-   :: forall (f4 :: k4 -> k3 -> k2 -> k1 -> Type) a4 a3 a2 a1-    . ( SingI a4, SDecide k4-      , SingI a3, SDecide k3-      , SingI a2, SDecide k2-      , SingI a1, SDecide k1 )-   => Some4 f4-   -> Maybe (f4 a4 a3 a2 a1) -- ^-fromSome4 = \(Some4 sa4' sa3' sa2' sa1' x) -> do-   Refl <- testEquality sa4' (sing :: Sing a4)-   Refl <- testEquality sa3' (sing :: Sing a3)-   Refl <- testEquality sa2' (sing :: Sing a2)-   Refl <- testEquality sa1' (sing :: Sing a1)-   return x-{-# INLINABLE fromSome4 #-}-------------------------------------------------------------------------------------- A @lens@-compatible 'Prism'' for constructing and deconstructing a 'Some1'.-_Some1-  :: forall (f1 :: k1 -> Type) a1-  .  (SingI a1, SDecide k1)-  => Prism' (Some1 f1) (f1 a1)-_Some1 = prism' some1 fromSome1-{-# INLINE _Some1 #-}---- A @lens@-compatible 'Prism'' for constructing and deconstructing a 'Some2'.-_Some2-  :: forall (f2 :: k2 -> k1 -> Type) a2 a1-  .  ( SingI a2, SDecide k2-     , SingI a1, SDecide k1 )-  => Prism' (Some2 f2) (f2 a2 a1)-_Some2 = prism' some2 fromSome2-{-# INLINE _Some2 #-}---- A @lens@-compatible 'Prism'' for constructing and deconstructing a 'Some3'.-_Some3-  :: forall (f3 :: k3 -> k2 -> k1 -> Type) a3 a2 a1-  .  ( SingI a3, SDecide k3-     , SingI a2, SDecide k2-     , SingI a1, SDecide k1 )-  => Prism' (Some3 f3) (f3 a3 a2 a1)-_Some3 = prism' some3 fromSome3-{-# INLINE _Some3 #-}---- A @lens@-compatible 'Prism'' for constructing and deconstructing a 'Some4'.-_Some4-  :: forall (f4 :: k4 -> k3 -> k2 -> k1 -> Type) a4 a3 a2 a1-  .  ( SingI a4, SDecide k4-     , SingI a3, SDecide k3-     , SingI a2, SDecide k2-     , SingI a1, SDecide k1 )-  => Prism' (Some4 f4) (f4 a4 a3 a2 a1)-_Some4 = prism' some4 fromSome4-{-# INLINE _Some4 #-}------------------------------------------------------------------------------------some1SingRep-  :: SingKind k1-  => Some1 (f1 :: k1 -> Type)-  -> DemoteRep k1 -- ^-some1SingRep = \(Some1 sa1 _) -> fromSing sa1-{-# INLINE some1SingRep #-}--some2SingRep-  :: (SingKind k2, SingKind k1)-  => Some2 (f2 :: k2 -> k1 -> Type)-  -> (DemoteRep k2, DemoteRep k1) -- ^-some2SingRep = \(Some2 sa2 sa1 _) -> (fromSing sa2, fromSing sa1)-{-# INLINE some2SingRep #-}--some3SingRep-  :: (SingKind k3, SingKind k2, SingKind k1)-  => Some3 (f3 :: k3 -> k2 -> k1 -> Type)-  -> (DemoteRep k3, DemoteRep k2, DemoteRep k1) -- ^-some3SingRep = \(Some3 sa3 sa2 sa1 _) ->-  (fromSing sa3, fromSing sa2, fromSing sa1)-{-# INLINE some3SingRep #-}--some4SingRep-  :: (SingKind k4, SingKind k3, SingKind k2, SingKind k1)-  => Some4 (f4 :: k4 -> k3 -> k2 -> k1 -> Type)-  -> (DemoteRep k4, DemoteRep k3, DemoteRep k2, DemoteRep k1) -- ^-some4SingRep = \(Some4 sa4 sa3 sa2 sa1 _) ->-  (fromSing sa4, fromSing sa3, fromSing sa2, fromSing sa1)-{-# INLINE some4SingRep #-}------------------------------------------------------------------------------------class Dict1 (c :: k0 -> Constraint) (f1 :: k1 -> k0) where-  -- | Runtime lookup of the @c (f1 a1)@ instance.-  dict1 :: Sing a1 -> Dict (c (f1 a1))--class Dict2 (c :: k0 -> Constraint) (f2 :: k2 -> k1 -> k0) where-  -- Runtime lookup of the @c (f2 a2 a1)@ instance.-  dict2 :: Sing a2 -> Sing a1 -> Dict (c (f2 a2 a1))--class Dict3 (c :: k0 -> Constraint) (f3 :: k3 -> k2 -> k1 -> k0) where-  -- Runtime lookup of the @c (f3 a3 a2 a1)@ instance.-  dict3 :: Sing a3 -> Sing a2 -> Sing a1 -> Dict (c (f3 a3 a2 a1))--class Dict4 (c :: k0 -> Constraint) (f4 :: k4 -> k3 -> k2 -> k1 -> k0) where-  -- Runtime lookup of the @c (f4 a4 a3 a2 a1)@ instance.-  dict4 :: Sing a4 -> Sing a3 -> Sing a2 -> Sing a1 -> Dict (c (f4 a4 a3 a2 a1))------------------------------------------------------------------------------------- Miscelaneous @lens@-compatible stuff.--type Prism s t a b-  = forall p f. (Choice p, Applicative f) => p a (f b) -> p s (f t)--type Prism' s a = Prism s s a a--prism :: (b -> t) -> (s -> Either t a) -> Prism s t a b-prism bt seta = dimap seta (either pure (fmap bt)) . right'-{-# INLINE prism #-}--prism' :: (b -> s) -> (s -> Maybe a) -> Prism s s a b-prism' bs sma = prism bs (\s -> maybe (Left s) Right (sma s))-{-# INLINE prism' #-}