htree (empty) → 0.1.1.0
raw patch · 19 files changed
+2242/−0 lines, 19 filesdep +QuickCheckdep +basedep +containers
Dependencies added: QuickCheck, base, containers, hspec, htree, quickcheck-instances, template-haskell, th-compat
Files
- CHANGELOG.md +5/−0
- LICENSE +661/−0
- README.md +69/−0
- htree.cabal +85/−0
- src/Data/HTree.hs +51/−0
- src/Data/HTree/Constraint.hs +71/−0
- src/Data/HTree/Existential.hs +194/−0
- src/Data/HTree/Families.hs +69/−0
- src/Data/HTree/Labeled.hs +178/−0
- src/Data/HTree/List.hs +111/−0
- src/Data/HTree/Tree.hs +253/−0
- test/Main.hs +12/−0
- test/Spec/HTree/Fixtures.hs +187/−0
- test/Spec/HTree/Fold.hs +71/−0
- test/Spec/HTree/Helpers.hs +18/−0
- test/Spec/HTree/Labeled.hs +25/−0
- test/Spec/HTree/Orphans.hs +64/−0
- test/Spec/HTree/TH.hs +103/−0
- test/Spec/HTree/Traverse.hs +15/−0
+ CHANGELOG.md view
@@ -0,0 +1,5 @@+# Revision history for HTree++## 0.1.0.0 -- 2024-07-21++* initial release
+ LICENSE view
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+ README.md view
@@ -0,0 +1,69 @@++[](https://nixos.org/)+[](https://www.haskell.org/)++[](https://mangoiv.com/htree)++# `htree`: heterogeneous rose tree ++This library implements a heterogeneous rose-tree (`HTree`) that is indexed by a+type-level rosetree (`TyTree`). ++It also offers some useful functions, highlights include:+- searching in the tree and creating evidence on the term-level via typeclasses+- record-dot syntax for accessing elements in the tree.+- mapping and traversing trees++## to develop++- with `direnv`: `direnv allow` +- only with nix: `nix develop`+- to run all checks: `nix flake check -Lv`+ systems configurations+- build with nix `nix build` (or on `ghc96`, `nix build .#ghc96-htree`)+- documentation in the form of continuously deployed haddock can be found at [mangoiv.srht.site](https://mangoiv.srht.site/htree/index.html)++## example++```haskell+pattern I :: forall a. a -> Identity a+pattern I a = Identity a++-- the type that the tree is going to be indexed by+type Ex =+ TyNode Int+ [ TyNode Int+ [ TyNode Int '[]+ , TyNode Bool '[]+ , TyNode String '[ TyNode Int '[]]+ ]+ , TyNode Int '[]+ ]++-- we create an HTree of the example type 'Ex'+ex :: HTree Identity Ex+ex =+ HNode 5 do+ HNode 12 do+ HNode 13 HNil+ ::: HNode (I False) HNil+ ::: HNode "test" (HNode 9 HNil ::: HNil)+ ::: HNil+ ::: HNode 43 HNil+ ::: HNil+ ++-- we can create a labeled Tree and search via DFS and BFS in it+-- the search happens on the type-level+type LabeledTree = TyNodeL "top" Int+ [ TyNodeL "inter" Int '[ TyNodeL "foo" Int '[] ]+ , TyNodeL "foo" Int '[]+ ]++-- >>> getElem @'DFS @"foo" @Int Proxy labeledTree+-- Identity 69+-- >>> getElem @'BFS @"foo" @Int Proxy labeledTree+-- Identity 67+labeledTree :: HTree Identity LabeledTree+labeledTree = 42 `HNodeL` HNodeL 4 (HNodeL 69 HNil ::: HNil) ::: HNodeL 67 HNil ::: HNil+```
+ htree.cabal view
@@ -0,0 +1,85 @@+cabal-version: 3.4+name: htree+tested-with: GHC ==9.2.8 || ==9.4.8 || ==9.6.4 || ==9.8.1+version: 0.1.1.0+synopsis:+ a library to build and work with heterogeneous, type level indexed rose trees++description:+ This library implements a heterogeneous rose-tree (HTree) that is indexed by a type-level rosetree (TyTree).++ It also offers some useful functions, highlights include:++ searching in the tree and creating evidence on the term-level via typeclasses+ record-dot syntax for accessing elements in the tree.+ mapping and traversing trees++license: AGPL-3.0-or-later+license-file: LICENSE+author: mangoiv+maintainer: contact@mangoiv.com+category: Data+build-type: Simple+extra-doc-files:+ CHANGELOG.md+ README.md++common warnings-and-imports+ ghc-options:+ -Wall -fprint-explicit-kinds -fprint-explicit-foralls+ -Wno-unticked-promoted-constructors -Wunused-packages++ default-extensions:+ BlockArguments+ DataKinds+ DerivingStrategies+ FunctionalDependencies+ GADTs+ LambdaCase+ NoStarIsType+ OverloadedLists+ OverloadedStrings+ PatternSynonyms+ QuantifiedConstraints+ TypeFamilies+ ViewPatterns++ build-depends: base >=4.16 && <5++library+ import: warnings-and-imports+ exposed-modules:+ Data.HTree+ Data.HTree.Constraint+ Data.HTree.Existential+ Data.HTree.Families+ Data.HTree.Labeled+ Data.HTree.List+ Data.HTree.Tree++ hs-source-dirs: src+ default-language: GHC2021++test-suite htree-test+ import: warnings-and-imports+ default-language: GHC2021+ other-modules:+ Spec.HTree.Fixtures+ Spec.HTree.Fold+ Spec.HTree.Helpers+ Spec.HTree.Labeled+ Spec.HTree.Orphans+ Spec.HTree.TH+ Spec.HTree.Traverse++ type: exitcode-stdio-1.0+ hs-source-dirs: test+ main-is: Main.hs+ build-depends:+ , containers+ , hspec+ , htree+ , QuickCheck+ , quickcheck-instances+ , template-haskell+ , th-compat
+ src/Data/HTree.hs view
@@ -0,0 +1,51 @@+-- | a module for useful reexports from the modules+module Data.HTree+ ( -- * lists+ HL.HList (..)++ -- * trees+ , HT.HTree (..)+ , pattern L.HNodeL+ , HT.TyTree (..)+ , type L.TyNodeL++ -- ** mapping a tree+ , HT.hmap+ , HT.hcmap++ -- ** traversing a tree+ , HT.htraverse+ , HT.hctraverse++ -- ** folding a tree++ -- *** value level+ , HT.hFoldMap+ , HT.hcFoldMap+ , HT.hFlatten++ -- *** type level+ , HT.FlattenTree+ , HT.FlattenForest++ -- ** searching a tree+ , L.Labeled (..)+ , L.HasField (..)+ , L.getElem++ -- * useful reexports+ , Re.Proxy (..)+ , Re.Type+ , Re.Constraint+ , Re.Dict+ , pattern Re.Dict+ , Re.withDict+ )+where++import Data.HTree.Constraint qualified as Re+import Data.HTree.Labeled qualified as L+import Data.HTree.List qualified as HL+import Data.HTree.Tree qualified as HT+import Data.Kind qualified as Re+import Data.Proxy qualified as Re
+ src/Data/HTree/Constraint.hs view
@@ -0,0 +1,71 @@+{-# LANGUAGE UndecidableSuperClasses #-}++-- | A couple of types to work with Constraints+module Data.HTree.Constraint+ ( -- * proving a constraint+ Has (..)++ -- ** synonyms for proving a constraint+ , HasTypeable+ , HasIs++ -- ** helpers to work with constraints+ , proves+ , Charge++ -- * Dict+ , type Dict+ , pattern Dict++ -- ** functions for working with 'Dict's+ , withDict+ )+where++import Data.Kind (Constraint, Type)+import Data.Proxy (Proxy (Proxy))+import Type.Reflection (Typeable)++-- | a functor useful for proving a constraint for some type+--+-- >>> import Data.Functor.Identity+-- >>> Proves @Eq (Identity (5 :: Int))+-- Proves (Identity 5)+type Has :: forall k. (k -> Constraint) -> (k -> Type) -> k -> Type+data Has c f k where+ Proves :: c k => f k -> Has c f k++-- | transform a 'Constraint' in something of kind @k -> 'Constraint'@ to be+-- able to use it in 'Has'+type Charge :: Constraint -> k -> Constraint+class c => Charge c a++instance c => Charge c a++-- | a Dict witnesses some constraint+type Dict :: Constraint -> Type+type Dict c = Has (Charge c) Proxy ()++-- | match on a 'Dict'+pattern Dict :: forall (c :: Constraint). forall. c => Dict c+pattern Dict = Proves Proxy++{-# COMPLETE Dict #-}++-- | destructing a 'Dict'+withDict :: Dict c -> (c => r) -> r+withDict d k = proves d (const k)++-- | destruct a 'Has'+proves :: Has c f a -> (c a => f a -> r) -> r+proves (Proves x) k = k x++-- | 'Has' but specialised to 'Typeable'+type HasTypeable :: (k -> Type) -> k -> Type+type HasTypeable = Has Typeable++-- | 'Has' but specialised to a constant type, @Some (HasIs k f)@ is isomorphic to @f k@+type HasIs :: k -> (k -> Type) -> k -> Type+type HasIs k = Has ((~) k)++deriving stock instance Show (f k) => Show (Has c f k)
+ src/Data/HTree/Existential.hs view
@@ -0,0 +1,194 @@+{-# LANGUAGE UndecidableInstances #-}++-- | Existential types and helpers to work with existentials 'HList's and 'HTree's+module Data.HTree.Existential+ ( -- * existential data types+ Some (..)+ , Some2 (..)++ -- * existential type synonyms+ , ETree+ , EList++ -- * working with existential HTrees/HLists functions+ , with+ , with2+ , withSomeHTree+ , withSomeHList+ , hcFoldEHList+ , hcFoldMapEHTree++ -- * useful functors to work with existential type-level structures+ , Has (..)+ , HasTypeable+ , HasIs++ -- ** working with 'Has'+ , withProves+ , prodHas+ , flipHas+ )+where++import Data.HTree.Constraint (Has (Proves), HasIs, HasTypeable, proves)+import Data.HTree.Families (Both)+import Data.HTree.List (HList (HCons, HNil))+import Data.HTree.Tree (HTree (HNode))+import Data.Kind (Type)+import Type.Reflection (SomeTypeRep (SomeTypeRep), Typeable, eqTypeRep, typeOf, (:~~:) (HRefl))++-- | a Some type that takes an arity one type constructor, this is for completeness+type Some :: forall l. (l -> Type) -> Type+data Some g where+ MkSome :: g k -> Some g++-- | take some existentai arity one type constructor and a function that takes the+-- non-existential one and returns some @r@ and return an @r@+with :: forall {l} (g :: l -> Type) r. Some g -> (forall m. g m -> r) -> r+with (MkSome a) f = f a++-- | a Some type that take an arity two type constructor, this is necessary+-- so that we avoid using composition on the type level or having visible+-- parameters to the type synonyms+type Some2 :: forall k l. (k -> l -> Type) -> k -> Type+data Some2 g f where+ MkSome2 :: g f k -> Some2 g f++-- | take some existential arity two type constructor and a function that takes the+-- non-existential one and returns some @r@ and return an @r@+with2+ :: forall {k} {l} (g :: k -> l -> Type) (f :: k) r+ . Some2 g f+ -> (forall m. g f m -> r)+ -> r+with2 (MkSome2 a) f = f a++-- | HTree but the type level tree is existential+type ETree :: forall k. (k -> Type) -> Type+type ETree = Some2 HTree++-- | HList but the type level list is existential+type EList :: forall k. (k -> Type) -> Type+type EList = Some2 HList++-- | 'with2' specialized to 'HTree's+withSomeHTree :: ETree f -> (forall t. HTree f t -> r) -> r+withSomeHTree = with2++-- | 'with2' specialized to 'HList's+withSomeHList :: EList f -> (forall xs. HList f xs -> r) -> r+withSomeHList = with2++-- | fold over existential hlists+hcFoldEHList+ :: forall c f y+ . (forall x. c x => f x -> y -> y)+ -> y+ -> EList (Has c f)+ -> y+hcFoldEHList f def el = with2 el \case+ HNil -> def+ HCons (Proves x) xs ->+ let y = hcFoldEHList f def (MkSome2 xs)+ in f x y++-- | fold over existential htrees+hcFoldMapEHTree+ :: forall c f y+ . Semigroup y+ => (forall a. c a => f a -> y)+ -> ETree (Has c f)+ -> y+hcFoldMapEHTree f et = with2 et \case+ HNode (Proves x) HNil -> f x+ HNode x@(Proves _) (y `HCons` ys) ->+ hcFoldMapEHTree f (MkSome2 y)+ <> hcFoldMapEHTree f (MkSome2 (HNode x ys))++-- | destruct 'Some', destruct 'Has'+withProves :: Some (Has c f) -> (forall a. c a => f a -> r) -> r+withProves x k = with x (`proves` k)++-- | condens the 'Has' constraints in an existential+prodHas :: forall c1 c2 f. Some (Has c1 (Has c2 f)) -> Some (Has (Both c1 c2) f)+prodHas x = withProves x \pc2 -> proves pc2 (MkSome . Proves)++-- | flip the constraints in an existential+flipHas :: forall c1 c2 f. Some (Has c1 (Has c2 f)) -> Some (Has c2 (Has c1 f))+flipHas x = withProves (prodHas x) (MkSome . Proves . Proves)++deriving stock instance (forall k. Show (g f k)) => Show (Some2 g f)++deriving stock instance (forall k. Show (g k)) => Show (Some g)++instance {-# OVERLAPPING #-} Typeable f => Show (Some (Has Typeable f)) where+ show (MkSome (Proves f)) =+ "(MkSome (Proves @Typeable " <> show (typeOf f) <> "))"++instance+ (forall x. Eq x => Eq (f x), Typeable f)+ => Eq (ETree (Has (Both Typeable Eq) f))+ where+ ex == ey =+ with2 ex \x -> with2 ey \y ->+ case (x, y) of+ (HNode (Proves m) ms, HNode (Proves n) ns) ->+ case eqTypeRep (typeOf m) (typeOf n) of+ Nothing -> False+ Just HRefl ->+ let go+ :: forall xs ys+ . HList (HTree (Has (Both Typeable Eq) f)) xs+ -> HList (HTree (Has (Both Typeable Eq) f)) ys+ -> Bool+ go HNil HNil = True+ go (m' `HCons` ms') (n' `HCons` ns') =+ MkSome2 m' == MkSome2 n' && go ms' ns'+ go _ _ = False+ in m == n && go ms ns++instance+ (forall x. Eq x => Eq (f x), Typeable f)+ => Eq (EList (Has (Both Typeable Eq) f))+ where+ ex == ey =+ with2 ex \x -> with2 ey \y ->+ case (x, y) of+ (HNil, HNil) -> True+ (HCons (Proves x') xs', HCons (Proves y') ys') ->+ case eqTypeRep (typeOf x') (typeOf y') of+ Nothing -> False+ Just HRefl -> x' == y' && MkSome2 xs' == MkSome2 ys'+ (_, _) -> False++instance Eq (f k) => Eq (EList (HasIs k f)) where+ ex == ey =+ with2 ex \x -> with2 ey \y ->+ case (x, y) of+ (HNil, HNil) -> True+ (HCons (Proves x') xs', HCons (Proves y') ys') ->+ (x' == y') && MkSome2 xs' == MkSome2 ys'+ (_, _) -> False++instance+ ( forall x. Eq x => Eq (f x)+ , Typeable f+ )+ => Eq (Some (Has Typeable (Has Eq f)))+ where+ MkSome (Proves (Proves x1)) == MkSome (Proves (Proves x2)) =+ case eqTypeRep (typeOf x1) (typeOf x2) of+ Just HRefl -> x1 == x2+ Nothing -> False++instance+ ( forall x. Ord x => Ord (f x)+ , Typeable f+ , Eq (Some (Has Typeable (Has Ord f)))+ )+ => Ord (Some (Has Typeable (Has Ord f)))+ where+ MkSome (Proves (Proves x1)) `compare` MkSome (Proves (Proves x2)) =+ case eqTypeRep (typeOf x1) (typeOf x2) of+ Just HRefl -> x1 `compare` x2+ Nothing -> SomeTypeRep (typeOf x1) `compare` SomeTypeRep (typeOf x2)
+ src/Data/HTree/Families.hs view
@@ -0,0 +1,69 @@+{-# LANGUAGE UndecidableInstances #-}+{-# LANGUAGE UndecidableSuperClasses #-}++-- | generic types and type families used in some of the modules+module Data.HTree.Families+ ( All+ , AllC+ , AllInv+ , Both+ , Not+ , Top+ , type (++)+ , type (||)+ )+where++import Data.Kind (Constraint)++-- | like 'Prelude.(++)' on the value level but on the type level+type (++) :: forall k. [k] -> [k] -> [k]+type family xs ++ ys where+ '[] ++ ys = ys+ (x : xs) ++ ys = x : xs ++ ys++-- | typelevel Or+type (||) :: Bool -> Bool -> Bool+type family a || b where+ 'True || b = 'True+ 'False || b = b++-- | like All but can be partially applied+type AllC :: forall k. (k -> Constraint) -> [k] -> Constraint+class All c xs => AllC c xs++instance All c xs => AllC c xs++-- | for all elements of a list, a contraint holds+type All :: forall k. (k -> Constraint) -> [k] -> Constraint+type family All c xs where+ All c '[] = ()+ All c (x : xs) = (c x, All c xs)++-- | the class that every type has an instance for+type Top :: k -> Constraint+class Top k++instance Top k++-- | like 'not' but on the type level+type Not :: Bool -> Bool+type family Not a where+ Not 'True = 'False+ Not 'False = 'True++infixr 5 ++++-- | 'All' but inversed: holds if all constraints in the list hold+type AllInv :: [k -> Constraint] -> k -> Constraint+class AllInv l k++instance AllInv '[] k++instance (c k, AllInv cs k) => AllInv (c ': cs) k++-- | product of two classes+type Both :: (k -> Constraint) -> (k -> Constraint) -> k -> Constraint+class (c1 a, c2 a) => Both c1 c2 a++instance (c1 a, c2 a) => Both c1 c2 a
+ src/Data/HTree/Labeled.hs view
@@ -0,0 +1,178 @@+{-# LANGUAGE UndecidableInstances #-}+{-# OPTIONS_GHC -Wno-orphans #-}++-- | This module implements a search in a typelevel tree+-- and offers a handy interface via @-XOverloaedRecordDot@ and 'GHC.Records.HasField'.+-- We can search in the tree via BFS or DFS.+-- Performance wise this doesn't make a difference, as the search is performed at+-- compile time anyway however, it can change the semantics if the tree contains an+-- element more than once, see the example in 'getElem'.+module Data.HTree.Labeled+ ( -- * Interface++ -- ** Labeled types+ Labeled (..)+ , pattern HNodeL+ , pattern HLeafL+ , type TyNodeL++ -- ** Getting elements+ , getElem+ , getElem'+ , SearchStrategy (..)++ -- ** Reexports+ , HasField (..)+ , Proxy (..)++ -- * Internal+ , HasField' (..)+ , Decide (..)+ , Elem+ , AnyElem+ , getElemWithPath+ )+where++import Data.HTree.Families (Not, type (||))+import Data.HTree.List (HList (HCons, HNil))+import Data.HTree.Tree (HForest, HTree (HNode), Path (Deeper, Farther, Here), TyForest, TyTree (TyNode))+import Data.Kind (Constraint, Type)+import Data.Proxy (Proxy (Proxy))+import GHC.Generics (Generic)+import GHC.Records (HasField (getField))++-- | a type syonym that allows for easy construction of TyTrees that have labeled nodes+type TyNodeL l a = 'TyNode (Labeled l a)++-- | a pattern that allows for direct construction and destruction of nodes with+-- labels+pattern HNodeL :: forall l a f ts. Functor f => f a -> HForest f ts -> HTree f ('TyNode (Labeled l a) ts)+pattern HNodeL x ts <- (HNode (fmap unLabel -> x) ts)+ where+ HNodeL x ts = HNode (MkLabeled <$> x) ts++{-# COMPLETE HNodeL #-}++-- | a labeled HNode Leaf+pattern HLeafL :: forall l a f. Functor f => f a -> HTree f ('TyNode (Labeled l a) '[])+pattern HLeafL x <- (HNode (fmap unLabel -> x) HNil)+ where+ HLeafL x = HNode (MkLabeled <$> x) HNil++-- | a newtype that is labeled with some typelevel tag+type Labeled :: forall l. l -> Type -> Type+newtype Labeled l a = MkLabeled {unLabel :: a}+ deriving stock (Show, Eq, Ord, Functor, Foldable, Traversable, Generic)++-- | gets an element given a path into the tree+getElemWithPath :: forall typ t f. Path typ t -> HTree f t -> f typ+getElemWithPath Here (HNode e _) = e+getElemWithPath (Farther pt) (HNode e (_ `HCons` ts)) = getElemWithPath pt (HNode e ts)+getElemWithPath (Deeper pt) (HNode _ (t `HCons` _)) = getElemWithPath pt t++-- | searches a tree for an element and returns that element+getElem' :: forall {proxy} strat typ t f. HasField' (strat :: SearchStrategy) typ t => proxy strat -> HTree f t -> f typ+getElem' _ = getElemWithPath (evidence @strat @typ @t Proxy)++-- | searches a tree for an element and returns that element, specialised to 'Labeled' and unwraps+--+-- >>> import Data.Functor.Identity+-- >>> type T = TyNodeL "top" Int [ TyNodeL "inter" Int '[ TyNodeL "foo" Int '[]], TyNodeL "foo" Int '[]]+-- >>> t :: HTree Identity T = 42 `HNodeL` HNodeL 4 (HNodeL 69 HNil `HCons` HNil) `HCons` HNodeL 67 HNil `HCons` HNil+-- >>> getElem @'DFS @"foo" @Int Proxy t+-- Identity 69+-- >>> getElem @'BFS @"foo" @Int Proxy t+-- Identity 67+getElem+ :: forall {proxy} strat l typ t f+ . ( HasField' (strat :: SearchStrategy) (Labeled l typ) t+ , Functor f+ )+ => proxy strat+ -> HTree f t+ -> f typ+getElem _ = fmap unLabel . getElemWithPath (evidence @strat @(Labeled l typ) @t Proxy)++-- the default behaviour is a breadth first search+instance (HasField' 'BFS (Labeled l typ) t, Functor f) => HasField l (HTree f t) (f typ) where+ getField = getElem @'BFS @l @typ @t Proxy++-- | simple typelevel predicate that tests whether some element is in a tree+type Elem :: forall k. k -> TyTree k -> Bool+type family Elem typ t where+ Elem a ('TyNode a ts) = 'True+ Elem a ('TyNode a' ts) = AnyElem a ts+ Elem a t = 'False++-- | typelevel predicate that tests whether the element is in any of the+-- subtrees+type AnyElem :: forall k. k -> TyForest k -> Bool+type family AnyElem typ ts where+ AnyElem a (t : ts) = Elem a t || AnyElem a ts+ AnyElem a '[] = 'False++-- | the search strategy used in 'HasField'', this is intended to be used only as a DataKind+type SearchStrategy :: Type+data SearchStrategy = DFS | BFS++-- | This is the helper class that creates evidence,+-- it implements a DFS together with Decide+type HasField' :: SearchStrategy -> Type -> TyTree Type -> Constraint+class HasField' strat typ t | strat t -> typ where+ evidence :: forall {proxy}. proxy strat -> Path typ t++-- | Together with HasField' implements a DFS in the tree+type Decide :: SearchStrategy -> Bool -> Type -> TyTree Type -> Constraint+class Decide strat elem typ t | strat t -> typ where+ evidence' :: forall {proxy :: forall k. k -> Type}. proxy strat -> proxy elem -> Path typ t++instance HasField' 'DFS typ ('TyNode typ (t : ts)) where+ evidence _ = Here++instance HasField' 'BFS typ ('TyNode typ (t : ts)) where+ evidence _ = Here++instance HasField' 'DFS typ ('TyNode typ '[]) where+ evidence _ = Here++instance HasField' 'BFS typ ('TyNode typ '[]) where+ evidence _ = Here++instance+ {-# OVERLAPPABLE #-}+ Decide+ 'BFS+ (AnyElem typ ts)+ typ+ ('TyNode typ' (t : ts))+ => HasField' 'BFS typ ('TyNode typ' (t : ts))+ where+ evidence _ = evidence' @'BFS @(AnyElem typ ts) @typ @('TyNode typ' (t : ts)) Proxy Proxy++instance+ {-# OVERLAPPABLE #-}+ Decide+ 'DFS+ (Not (Elem typ t))+ typ+ ('TyNode typ' (t : ts))+ => HasField' 'DFS typ ('TyNode typ' (t : ts))+ where+ evidence _ = evidence' @'DFS @(Not (Elem typ t)) @typ @('TyNode typ' (t : ts)) Proxy Proxy++instance+ HasField' strat typ t+ => Decide strat 'False typ ('TyNode typ' (t : ts'))+ where+ evidence' _ _ = Deeper (evidence @strat @typ @t Proxy)++instance+ HasField' strat typ ('TyNode typ' ts)+ => Decide strat 'True typ ('TyNode typ' (t' : ts))+ where+ evidence' _ _ = Farther (evidence @strat @typ @('TyNode typ' ts) Proxy)++infixr 4 `HNodeL`++infixr 4 `TyNodeL`
+ src/Data/HTree/List.hs view
@@ -0,0 +1,111 @@+{-# OPTIONS_GHC -Wno-unrecognised-pragmas #-}++{-# HLINT ignore "Eta reduce" #-}++-- | implements a heterogeneous list to use for forests of heterogeneous trees+module Data.HTree.List+ ( -- * heterogeneous list+ HList ((:::), HSing, ..)++ -- * mapping+ , hcmap+ , hmap++ -- * traversing+ , htraverse+ , hctraverse++ -- * folding+ , hcFold++ -- * helpers+ , allTopHList+ , hconcat+ )+where++import Data.Functor.Identity (Identity (Identity, runIdentity))+import Data.HTree.Constraint (withDict, pattern Dict, type Dict)+import Data.HTree.Families (All, Top, type (++))+import Data.Kind (Type)++-- | A heterogeneous list+--+-- >>> "bla" `HCons` 23 `HCons` HNil :: HList Identity '[ String, Int ]+-- HCons (Identity "bla") (HCons (Identity 23) HNil)+type HList :: forall k. (k -> Type) -> [k] -> Type+data HList f ts where+ HCons :: forall f x xs. f x -> HList f xs -> HList f (x : xs)+ HNil :: forall f. HList f '[]++-- | pattern synonym for 'HCons'+--+-- >>> t = "bla" ::: 23 ::: HNil :: HList Identity '[ String, Int ]+-- >>> t+-- HCons (Identity "bla") (HCons (Identity 23) HNil)+-- >>> case t of (x ::: _) -> runIdentity x+-- "bla"+pattern (:::) :: forall f x xs. f x -> HList f xs -> HList f (x : xs)+pattern x ::: xs = HCons x xs++-- | pattern that allows to construct a singleton HList+--+-- >>> HSing 42 :: HList Identity '[ Int ]+-- HCons (Identity 42) HNil+pattern HSing :: forall f a. f a -> HList f '[a]+pattern HSing x = HCons x HNil++-- | map with a function that maps forall f a+hmap :: forall f g xs. (forall a. f a -> g a) -> HList f xs -> HList g xs+hmap f l = withDict (allTopHList l) $ hcmap @Top @f @g f l++-- | map with a constraint that holds for all elements of the list+--+-- >>> import Data.Functor.Const+-- >>> hcmap @Show (Const . show . runIdentity) (42 `HCons` HSing "bla" :: HList Identity '[ Int, String ])+-- HCons (Const "42") (HCons (Const "\"bla\"") HNil)+hcmap :: forall c f g xs. All c xs => (forall a. c a => f a -> g a) -> HList f xs -> HList g xs+hcmap f = runIdentity . hctraverse @c @Identity @f @g (Identity . f)++-- | traverse a structure with a function+htraverse :: forall t f g xs. Applicative t => (forall a. f a -> t (g a)) -> HList f xs -> t (HList g xs)+htraverse f l = withDict (allTopHList l) $ hctraverse @Top @t @f @g f l++-- | traverse a structure such that a constraint holds; this is the workhorse of mapping and traversing+--+-- >>> import Data.Functor.Const+-- >>> hctraverse @Show (Just . Const . show . runIdentity) (42 `HCons` HSing "bla" :: HList Identity '[ Int, String ])+-- Just (HCons (Const "42") (HCons (Const "\"bla\"") HNil))+hctraverse :: forall c t f g xs. (All c xs, Applicative t) => (forall a. c a => f a -> t (g a)) -> HList f xs -> t (HList g xs)+hctraverse _ HNil = pure HNil+hctraverse f (HCons x xs) = HCons <$> f x <*> hctraverse @c @t @f @g f xs++-- | foldr for HLists.+hcFold :: forall c f b xs. All c xs => (forall a. c a => f a -> b -> b) -> b -> HList f xs -> b+hcFold _ def HNil = def+hcFold f def (x `HCons` xs) = f x $ hcFold @c f def xs++-- | witnesses that for all HLists, we can always derive the All Top constraint+allTopHList :: forall f xs. HList f xs -> Dict (All Top xs)+allTopHList HNil = Dict+allTopHList (HCons _ xs) = case allTopHList xs of+ Dict -> Dict++-- | concats two heterogeneous lists+hconcat :: forall f xs ys. HList f xs -> HList f ys -> HList f (xs ++ ys)+hconcat HNil ys = ys+hconcat (x `HCons` xs) ys = x `HCons` xs `hconcat` ys++infixr 5 `HCons`++infixr 5 :::++infixr 5 `hconcat`++deriving stock instance Show (HList f '[])++deriving stock instance (Show (f x), Show (HList f xs)) => Show (HList f (x : xs))++deriving stock instance Eq (HList f '[])++deriving stock instance (Eq (f x), Eq (HList f xs)) => Eq (HList f (x : xs))
+ src/Data/HTree/Tree.hs view
@@ -0,0 +1,253 @@+{-# LANGUAGE UndecidableInstances #-}+{-# LANGUAGE UndecidableSuperClasses #-}+{-# OPTIONS_GHC -Wno-unrecognised-pragmas #-}++{-# HLINT ignore "Eta reduce" #-}++-- | implements a heterogeneous tree ('HTree') indexed by a homogeneous type level tree ('TyTree')+module Data.HTree.Tree+ ( -- * type level tree+ TyTree (..)+ , TyForest++ -- * heterogeneous tree+ , HTree (HLeaf, ..)+ , HForest++ -- * mapping++ -- ** value level+ , hmap+ , hcmap++ -- * type level+ , TreeMap+ , ForestMap++ -- * traversing+ , htraverse+ , hctraverse++ -- * folding++ -- ** value level+ , hFoldMap+ , hcFoldMap+ , hFlatten++ -- ** type level+ , FlattenTree+ , FlattenForest++ -- * paths into the htree and things you can do with those+ , Path (..)+ , replaceAt++ -- * helpful constraints+ , AllTree+ , AllTreeC+ , AllForest++ -- ** helpers for witnessing the constraints+ , allTopHTree+ , allTopHForest+ )+where++import Data.Functor.Identity (Identity (Identity, runIdentity))+import Data.HTree.Constraint (Dict, withDict, pattern Dict)+import Data.HTree.Families (All, Top, type (++))+import Data.HTree.List (HList (HCons, HNil), hconcat)+import Data.HTree.List qualified as L+import Data.Kind (Constraint, Type)++-- | a type level rose-tree that is only intended to+-- store something of a certain kind, e.g. Type+type TyTree :: forall k. k -> Type+data TyTree k where+ TyNode :: forall a. a -> TyForest a -> TyTree a++-- | a forest of TyTrees+type TyForest :: forall k. k -> Type+type TyForest a = [TyTree a]++-- | a heterogeneous rose tree indexed by a TyTree+type HTree :: forall k. (k -> Type) -> TyTree k -> Type+data HTree f t where+ HNode :: forall f a ts. f a -> HForest f ts -> HTree f ('TyNode a ts)++-- | a pattern synonym for the leaf of an HTree+pattern HLeaf :: forall f a. forall. f a -> HTree f ('TyNode a '[])+pattern HLeaf a = HNode a HNil++-- | A forest of heterogeneous rose trees+type HForest :: forall k. (k -> Type) -> TyForest k -> Type+type HForest f ts = HList (HTree f) ts++-- | map a function over an HTree+hmap+ :: forall {k} (f :: k -> Type) (g :: k -> Type) (t :: TyTree k)+ . (forall a. f a -> g a)+ -> HTree f t+ -> HTree g t+hmap f t = withDict (allTopHTree t) $ hcmap @Top @f @g f t++-- | map a function with a constraint over an HTree+hcmap+ :: forall+ {k}+ (c :: k -> Constraint)+ (f :: k -> Type)+ (g :: k -> Type)+ (t :: TyTree k)+ . AllTree c t+ => (forall a. c a => f a -> g a)+ -> HTree f t+ -> HTree g t+hcmap f = runIdentity . hctraverse @c @Identity @f @g (Identity . f)++-- | traverse a structure with a function+htraverse+ :: forall+ {k}+ (h :: Type -> Type)+ (f :: k -> Type)+ (g :: k -> Type)+ (t :: TyTree k)+ . Applicative h+ => (forall a. f a -> h (g a))+ -> HTree f t+ -> h (HTree g t)+htraverse f t = withDict (allTopHTree t) $ hctraverse @Top f t++-- | traverse a structure such that a constraint holds; this is the workhorse of mapping and traversing+hctraverse+ :: forall+ {k}+ (c :: k -> Constraint)+ (h :: Type -> Type)+ (f :: k -> Type)+ (g :: k -> Type)+ (t :: TyTree k)+ . (AllTree c t, Applicative h)+ => (forall a. c a => f a -> h (g a))+ -> HTree f t+ -> h (HTree g t)+hctraverse f (HNode x ts) = HNode <$> f x <*> L.hctraverse @(AllTreeC c) @h @(HTree f) @(HTree g) (hctraverse @c f) ts++-- | map a functor over a TyTree+type TreeMap :: forall k l. (k -> l) -> TyTree k -> TyTree l+type family TreeMap f t where+ forall f x. TreeMap f ('TyNode x '[]) = 'TyNode (f x) '[]+ forall f x xs. TreeMap f ('TyNode x xs) = 'TyNode (f x) (ForestMap f xs)++-- | map a functor over a TyForest+type ForestMap :: forall k l. (k -> l) -> TyForest k -> TyForest l+type family ForestMap f t where+ ForestMap _ '[] = '[]+ forall f n ns. ForestMap f (n : ns) = TreeMap f n : ForestMap f ns++-- | monoidally folds down a tree to a single value using a constraint on+-- the element in the wrapping functor, this is similar to 'foldMap'+hcFoldMap+ :: forall+ {k}+ (c :: k -> Constraint)+ (f :: k -> Type)+ (t :: TyTree k)+ (b :: Type)+ . (AllTree c t, Semigroup b)+ => (forall a. c a => f a -> b)+ -> HTree f t+ -> b+hcFoldMap f (HNode x HNil) = f x+hcFoldMap f (HNode x (y `HCons` ys)) = hcFoldMap @c f y <> hcFoldMap @c f (HNode x ys)++-- | monoidally folds down a tree to a single value, this is similar to 'foldMap'+hFoldMap+ :: forall+ {k}+ (f :: k -> Type)+ (t :: TyTree k)+ (b :: Type)+ . Semigroup b+ => (forall a. f a -> b)+ -> HTree f t+ -> b+hFoldMap f t = withDict (allTopHTree t) $ hcFoldMap @Top f t++-- | flatten a heterogeneous tree down to a heterogeneous list+hFlatten+ :: forall+ {k}+ (f :: k -> Type)+ (t :: TyTree k)+ . HTree f t+ -> HList f (FlattenTree t)+hFlatten (HNode x xs) = x `HCons` hflattenForest xs+ where+ hflattenForest :: forall ts. HForest f ts -> HList f (FlattenForest ts)+ hflattenForest HNil = HNil+ hflattenForest (y `HCons` ys) = hFlatten y `hconcat` hflattenForest ys++-- | a type family that flattens a tree down to a list+type FlattenTree :: forall k. TyTree k -> [k]+type family FlattenTree t where+ forall x xs. FlattenTree ('TyNode x xs) = x : FlattenForest xs++-- | a type family that flattens a forest down to a list+type FlattenForest :: forall k. TyForest k -> [k]+type family FlattenForest f where+ FlattenForest '[] = '[]+ FlattenForest (x : xs) = FlattenTree x ++ FlattenForest xs++-- | a constraint holds for all elements in the tree+type AllTree :: forall k. (k -> Constraint) -> TyTree k -> Constraint+type family AllTree c ts where+ forall c x ts. AllTree c ('TyNode x ts) = (c x, AllForest c ts)++-- | constraint synonym for AllTree+type AllTreeC :: forall k. (k -> Constraint) -> TyTree k -> Constraint+class AllTree c ts => AllTreeC c ts++instance forall c ts. AllTree c ts => AllTreeC c ts++-- | a constraint holds for all elements in the forest+type AllForest :: forall k. (k -> Constraint) -> TyForest k -> Constraint+type family AllForest c t where+ AllForest c xs = All (AllTreeC c) xs++-- | witnesses that for any HTree the constraint AllTree Top always holds+allTopHTree :: forall f t. HTree f t -> Dict (AllTree Top t)+allTopHTree (HNode _ (allTopHForest -> Dict)) = Dict++-- | witnesses that for any HForest the constraint AllForest Top always holds+allTopHForest :: forall f t. HForest f t -> Dict (AllForest Top t)+allTopHForest HNil = Dict+allTopHForest (HCons (allTopHTree -> Dict) (allTopHForest -> Dict)) = Dict++-- | replace an element at a certain path.+replaceAt :: Path typ t -> f typ -> HTree f t -> HTree f t+replaceAt Here x (HNode _ xs) = HNode x xs+replaceAt (Deeper pt) x (HNode y (t `HCons` ts)) = HNode y (replaceAt pt x t `HCons` ts)+replaceAt (Farther pt) x (HNode y (t `HCons` ts)) = let HNode y' ts' = replaceAt pt x (HNode y ts) in HNode y' (t `HCons` ts')++-- | provides evidence that an element is in the tree by+-- providing a path to the element+type Path :: forall k. k -> TyTree k -> Type+data Path k t where+ Here :: forall a ts. Path a ('TyNode a ts)+ Deeper :: forall a b t ts. Path a t -> Path a ('TyNode b (t : ts))+ Farther :: forall a b t ts. Path a ('TyNode b ts) -> Path a ('TyNode b (t : ts))++infixr 4 `HNode`++infixr 4 `TyNode`++deriving stock instance (Show (f a), Show (HForest f t)) => Show (HTree f ('TyNode a t))++deriving stock instance (Eq (f a), Eq (HForest f t)) => Eq (HTree f ('TyNode a t))++deriving stock instance Show (Path typ t)++deriving stock instance Eq (Path typ t)
+ test/Main.hs view
@@ -0,0 +1,12 @@+module Main (main) where++import Spec.HTree.Fold qualified as Fold+import Spec.HTree.Labeled qualified as Labeled+import Spec.HTree.Traverse qualified as Traverse+import Test.Hspec (hspec)++main :: IO ()+main = hspec do+ Labeled.spec+ Traverse.spec+ Fold.spec
+ test/Spec/HTree/Fixtures.hs view
@@ -0,0 +1,187 @@+module Spec.HTree.Fixtures+ ( type ExL+ , exL+ , type Ex+ , ex+ , exShown+ , exC+ , type ExReal+ , exReal+ , type I+ , pattern I+ , unI+ , type K+ , pattern K+ , unK+ , type ExIntegral+ , exIntegral+ , type ExBfsDfs+ , exBfsDfs+ )+where++import Data.Functor.Const (Const (Const, getConst))+import Data.Functor.Identity (Identity (Identity, runIdentity))+import Data.HTree.Labeled (pattern HNodeL, type TyNodeL)+import Data.HTree.List (HList (HNil, HSing, (:::)))+import Data.HTree.Tree (HTree (HLeaf, HNode), TyTree (TyNode))+import Data.Tree (Tree (Node))++type K = Const++pattern K :: forall a b. a -> K a b+pattern K a = Const a++unK :: forall a b. K a b -> a+unK = getConst++type I = Identity++pattern I :: forall a. a -> I a+pattern I a = Identity a++unI :: forall a. I a -> a+unI = runIdentity++type ExL =+ TyNodeL+ "top"+ Int+ [ TyNodeL+ "b"+ Int+ [ TyNodeL "c" Int '[]+ , TyNodeL "d" Bool '[]+ , TyNodeL+ "e"+ String+ '[ TyNodeL "bla" Int '[]+ ]+ ]+ , TyNodeL "a" Int '[]+ ]++exL :: HTree Identity ExL+exL =+ HNodeL 5 do+ HNodeL 12 do+ HNodeL 13 HNil+ ::: HNodeL (I False) HNil+ ::: HNodeL "test" (HNodeL 9 HNil ::: HNil)+ ::: HNil+ ::: HNodeL 42 HNil+ ::: HNil++type Ex =+ TyNode+ Int+ [ TyNode+ Int+ [ TyNode Int '[]+ , TyNode Bool '[]+ , TyNode String '[ 'TyNode Int '[]]+ ]+ , 'TyNode Int '[]+ ]++ex :: HTree Identity Ex+ex =+ HNode 5 do+ HNode 12 do+ HNode 13 HNil+ ::: HNode (I False) HNil+ ::: HNode "test" (HNode 9 HNil ::: HNil)+ ::: HNil+ ::: HNode 43 HNil+ ::: HNil++exShown :: Tree String+exShown =+ Node+ "5"+ [ Node+ "12"+ [Node "13" [], Node "False" [], Node "\"test\"" [Node "9" []]]+ , Node "43" []+ ]++exC :: HTree (K Int) Ex+exC =+ HNode 5 do+ HNode 12 do+ HNode 13 HNil+ ::: HNode 13 HNil+ ::: HNode 5 (HNode 9 HNil ::: HNil)+ ::: HNil+ ::: HNode 43 HNil+ ::: HNil++type ExReal =+ 'TyNode+ Int+ '[ 'TyNode+ Float+ '[ 'TyNode Double '[]+ , 'TyNode Float '[]+ , 'TyNode+ Integer+ '[ 'TyNode Float '[]]+ ]+ , 'TyNode+ Int+ '[ 'TyNode Float '[]]+ ]++exReal :: HTree I ExReal+exReal =+ HNode 42 do+ HNode 2.7 do+ HLeaf 13.7+ ::: HLeaf 12.2+ ::: HSing do+ HNode 14 do+ HSing (HLeaf (I 12.7))+ ::: HNode 12 do HSing (HLeaf 3.14)+ ::: HNil++type ExIntegral =+ 'TyNode+ Int+ [ TyNode+ Integer+ '[ TyNode Int '[]+ , TyNode Integer '[]+ , TyNode+ Integer+ '[TyNode Int '[]]+ ]+ , TyNode+ Int+ '[TyNode Int '[]]+ ]++exIntegral :: HTree I ExIntegral+exIntegral = HNode 42 do+ HNode 7 do+ HLeaf 13 ::: HLeaf 122 ::: HSing do+ HNode 14 (HSing (HLeaf 127))+ ::: HNode 12 (HSing (HLeaf 31))+ ::: HNil++type ExBfsDfs =+ TyNodeL+ "top"+ Int+ [ TyNodeL+ "inter"+ Int+ '[ TyNodeL "foo" Int '[]+ ]+ , TyNodeL "foo" Int '[]+ ]++exBfsDfs :: HTree I ExBfsDfs+exBfsDfs = HNodeL 42 do+ HNodeL 4 (HSing (HNodeL 69 HNil))+ ::: HNodeL 67 HNil+ ::: HNil
+ test/Spec/HTree/Fold.hs view
@@ -0,0 +1,71 @@+module Spec.HTree.Fold (spec) where++import Data.Functor.Identity (Identity)+import Data.HTree (hcFoldMap)+import Data.HTree.Existential (Has (Proves), Some (MkSome), hcFoldEHList, hcFoldMapEHTree)+import Data.Semigroup (Product (Product, getProduct), Sum (Sum, getSum))+import Data.Set (Set, empty, insert, singleton)+import Data.Tree (Tree)+import Data.Typeable (Typeable, typeOf)+import GHC.Real ((%))+import Spec.HTree.Fixtures (exIntegral, exReal)+import Spec.HTree.Orphans (toEList, toETree)+import Test.Hspec (Spec, describe, it)+import Test.Hspec.QuickCheck (modifyMaxSuccess, prop)+import Test.QuickCheck (Property, (===))++spec :: Spec+spec = do+ describe "folding an HTree of numbers" do+ it "calculates the correct sum" (31649046316921651 % 281474976710656 == getSum (hcFoldMap @Real (Sum . toRational) exReal))+ it "calculates the correct product" (308407698144 == getProduct (hcFoldMap @Integral (Product . toInteger) exIntegral))+ modifyMaxSuccess (* 10) do+ prop "yields the same results as expected for many Lists" $+ foldsSameList @Identity+ prop "yields the same results as expected for many trees" $+ foldsSameTree @Identity++foldsSameList+ :: forall f+ . ( forall x. Eq x => Eq (f x)+ , forall x. Ord x => Ord (f x)+ , Typeable f+ , Applicative f+ )+ => [Some (Has Typeable (Has Ord f))]+ -> Property+foldsSameList l =+ let folded :: Set (String, Some (Has Typeable (Has Ord f)))+ folded =+ foldMap+ (\(MkSome (Proves f)) -> singleton (show (typeOf f), MkSome (Proves f)))+ l+ hfolded :: Set (String, Some (Has Typeable (Has Ord f)))+ hfolded =+ hcFoldEHList @Typeable+ (\f acc -> (show (typeOf f), MkSome (Proves f)) `insert` acc)+ empty+ (toEList l)+ in folded === hfolded++foldsSameTree+ :: forall f+ . ( forall x. Eq x => Eq (f x)+ , forall x. Ord x => Ord (f x)+ , Typeable f+ , Applicative f+ )+ => Tree (Some (Has Typeable (Has Ord f)))+ -> Property+foldsSameTree l =+ let folded :: Set (String, Some (Has Typeable (Has Ord f)))+ folded =+ foldMap+ (\(MkSome (Proves f)) -> singleton (show (typeOf f), MkSome (Proves f)))+ l+ hfolded :: Set (String, Some (Has Typeable (Has Ord f)))+ hfolded =+ hcFoldMapEHTree @Typeable+ (\f -> singleton (show (typeOf f), MkSome (Proves f)))+ (toETree l)+ in folded === hfolded
+ test/Spec/HTree/Helpers.hs view
@@ -0,0 +1,18 @@+module Spec.HTree.Helpers (forgetHTree, forgetHList, liftedWith) where++import Data.Functor.Const (Const (Const, getConst))+import Data.HTree.Existential (Some (MkSome))+import Data.HTree.List (HList (HCons, HNil), hmap)+import Data.HTree.Tree (HTree (HNode))+import Data.Kind (Type)+import Data.Tree (Tree (Node))++forgetHTree :: forall a t. HTree (Const a) t -> Tree a+forgetHTree (HNode x ts) = Node (getConst x) (forgetHList (hmap (Const . forgetHTree) ts))++forgetHList :: forall a l. HList (Const a) l -> [a]+forgetHList HNil = []+forgetHList (HCons x xs) = getConst x : forgetHList xs++liftedWith :: forall {l} (g :: l -> Type) f r. Functor f => f (Some g) -> (forall m. g m -> r) -> f r+liftedWith a f = fmap \case { MkSome b -> f b } a
+ test/Spec/HTree/Labeled.hs view
@@ -0,0 +1,25 @@+{-# LANGUAGE OverloadedRecordDot #-}+{-# OPTIONS_GHC -fprint-potential-instances -fprint-typechecker-elaboration #-}++module Spec.HTree.Labeled (spec) where++import Data.HTree.Labeled (Proxy (Proxy), SearchStrategy (BFS, DFS), getElem)+import Spec.HTree.Fixtures (exBfsDfs, exL, unI)+import Test.Hspec (Spec, describe, it)++spec :: Spec+spec = describe "elements in the example get returned as expected" do+ it "has top node 5" do+ (5 :: Int) == unI exL.top+ it "has a node 42" do+ (42 :: Int) == unI exL.a+ it "has bla node 9" do+ (9 :: Int) == unI exL.bla+ it "has d node False" do+ not $ unI exL.d+ it "has e node \"test\"" do+ ("test" :: String) == unI exL.e+ it "finds int via BFS" do+ unI (getElem @BFS @"foo" @Int Proxy exBfsDfs) == 67+ it "finds int via DFS" do+ unI (getElem @DFS @"foo" @Int Proxy exBfsDfs) == 69
+ test/Spec/HTree/Orphans.hs view
@@ -0,0 +1,64 @@+{-# LANGUAGE ImpredicativeTypes #-}+{-# LANGUAGE PartialTypeSignatures #-}+{-# LANGUAGE TemplateHaskell #-}+{-# LANGUAGE UndecidableInstances #-}+{-# LANGUAGE NoOverloadedLists #-}+{-# OPTIONS_GHC -Wno-orphans #-}++module Spec.HTree.Orphans where++import Data.HTree (HTree (HNode))+import Data.HTree.Existential (EList, ETree, Has (Proves), Some (MkSome), Some2 (MkSome2))+import Data.HTree.Families (Both)+import Data.HTree.List (HList (HCons, HNil))+import Data.Maybe (catMaybes)+import Data.Proxy (Proxy (Proxy))+import Data.Tree (Tree (Node))+import Spec.HTree.Helpers (liftedWith)+import Spec.HTree.TH (discoverInstancesTypeable)+import Test.QuickCheck.Arbitrary (Arbitrary (arbitrary))+import Test.QuickCheck.Gen (Gen, oneof)+import Test.QuickCheck.Instances ()+import Type.Reflection (Typeable, eqTypeRep, typeRep, (:~~:) (HRefl))++embedType :: [Some (Has Typeable Gen)]+embedType = liftedWith $$(discoverInstancesTypeable @Arbitrary) \(Proves (Proxy :: Proxy a)) ->+ MkSome $ Proves $ arbitrary @a++embedArbOrd :: [Some (Has (Both Typeable Ord) Gen)]+embedArbOrd =+ catMaybes $ concat $ liftedWith $$(discoverInstancesTypeable @Ord) \(Proves (Proxy :: Proxy a)) ->+ liftedWith $$(discoverInstancesTypeable @Arbitrary) \(Proves (Proxy :: Proxy b)) ->+ case eqTypeRep (typeRep @a) (typeRep @b) of+ Nothing -> Nothing+ Just HRefl -> Just (MkSome (Proves $ arbitrary @a))++toEList :: [Some x] -> EList x+toEList [] = MkSome2 HNil+toEList (MkSome x : xs) =+ case toEList xs of+ MkSome2 t -> MkSome2 (HCons x t)++toETree :: Tree (Some f) -> ETree f+toETree (Node (MkSome t) []) = MkSome2 (HNode t HNil)+toETree (Node t' (t : ts)) =+ case (toETree t, toETree (Node t' ts)) of+ (MkSome2 ht, MkSome2 (HNode ht' hts)) -> MkSome2 (HNode ht' (HCons ht hts))++instance Applicative f => Arbitrary (EList (Has Typeable f)) where+ arbitrary = toEList <$> arbitrary++instance Applicative f => Arbitrary (ETree (Has Typeable f)) where+ arbitrary = toETree <$> arbitrary++instance Applicative f => Arbitrary (Some (Has Typeable f)) where+ arbitrary = oneof $ liftedWith embedType \(Proves gen :: Has Typeable Gen b) ->+ MkSome . Proves . pure <$> gen++instance {-# OVERLAPPING #-} Applicative f => Arbitrary (Some (Has Typeable (Has Ord f))) where+ arbitrary = oneof $ liftedWith embedArbOrd \(Proves gen :: Has (Both Typeable Ord) Gen b) ->+ MkSome . Proves . Proves . pure <$> gen++instance (forall x. Eq x => Eq (f x), Typeable f) => Eq (Some (Has Typeable (Has Ord f))) where+ MkSome (Proves (Proves x)) == MkSome (Proves (Proves y)) =+ MkSome (Proves @Typeable (Proves @Eq x)) == MkSome (Proves @Typeable (Proves @Eq y))
+ test/Spec/HTree/TH.hs view
@@ -0,0 +1,103 @@+{-# LANGUAGE ImpredicativeTypes #-}+{-# LANGUAGE TemplateHaskell #-}+{-# LANGUAGE NoOverloadedLists #-}+{-# OPTIONS_GHC -fno-print-explicit-runtime-reps #-}++-- | adapated from 'discoverInstances' from https://hackage.haskell.org/package/discover-instances-0.1.0.0+module Spec.HTree.TH (discoverInstances, discoverInstancesTypeable) where++import Data.HTree.Existential (Has (Proves), Some (MkSome))+import Data.HTree.Families (Both)+import Data.Kind (Constraint)+import Data.Proxy (Proxy (Proxy))+import Data.Typeable (Typeable, typeRep)+import Language.Haskell.TH (Type)+import Language.Haskell.TH.Syntax+ ( Dec (InstanceD)+ , Exp (ListE)+ , InstanceDec+ , Q+ , TExp (TExp, unType)+ , Type (..)+ , mkName+ , reifyInstances+ , reportWarning+ , unsafeTExpCoerce+ )+import Language.Haskell.TH.Syntax.Compat+ ( SpliceQ+ , examineSplice+ , liftSplice+ )++discoverInstances :: forall {k} (c :: k -> Constraint). Typeable c => SpliceQ [Some (Has c Proxy)]+discoverInstances = liftSplice $ do+ let className = show (typeRep (Proxy @c))+ listTE :: [TExp a] -> TExp [a]+ listTE = TExp . ListE . map unType+ instanceDecs <- reifyInstances (mkName className) [VarT (mkName "a")]++ dicts <- listTE <$> traverse decToDict instanceDecs++ examineSplice [||concat $$(liftSplice $ pure dicts)||]++decToDict :: forall {k} (c :: k -> Constraint). InstanceDec -> Q (TExp [Some (Has c Proxy)])+decToDict = \case+ InstanceD _moverlap cxt typ _decs ->+ case cxt of+ [] -> do+ let t = case typ of+ AppT _ t' -> stripSig t'+ _ -> t+ stripSig (SigT a _) = a+ stripSig x = x+ proxy = [|Proxy :: Proxy $(pure t)|]+ unsafeTExpCoerce [|[MkSome (Proves $proxy)]|]+ _ -> examineSplice [||[]||]+ _ -> do+ reportWarning "discoverInstances called on 'reifyInstances' somehow returned something that wasn't a type class instance."+ examineSplice [||[]||]++discoverInstancesTypeable :: forall {k} (c :: k -> Constraint). Typeable c => SpliceQ [Some (Has (Both Typeable c) Proxy)]+discoverInstancesTypeable = liftSplice $ do+ let className = show (typeRep (Proxy @c))+ listTE :: [TExp a] -> TExp [a]+ listTE = TExp . ListE . map unType+ instanceDecs <- reifyInstances (mkName className) [VarT (mkName "a")]++ dicts <- listTE <$> traverse decToDictTypeable instanceDecs++ examineSplice [||concat $$(liftSplice $ pure dicts)||]++decToDictTypeable :: forall {k} (c :: k -> Constraint). InstanceDec -> Q (TExp [Some (Has (Both Typeable c) Proxy)])+decToDictTypeable = \case+ InstanceD _moverlap cxt typ _decs ->+ case cxt of+ [] -> do+ let t :: Maybe Type = clean =<< removeClass typ+ removeClass :: Type -> Maybe Type+ removeClass (AppT _ x) = pure x+ removeClass (SigT x _) = removeClass x+ removeClass _ = Nothing++ clean :: Type -> Maybe Type+ clean (AppT f x) = AppT <$> clean f <*> clean x+ clean (SigT x _) = clean x+ clean (VarT _) = Nothing+ clean (ConT n) = pure $ ConT n+ clean (ParensT n) = pure $ ParensT n+ clean (TupleT n) = pure $ TupleT n+ clean ListT = pure ListT+ clean _ = Nothing++ proxy = case t of+ Just t' -> Just [|Proxy :: Proxy $(pure t')|]+ Nothing -> Nothing++ unsafeTExpCoerce $ case proxy of+ Just proxy' -> [|[MkSome (Proves @(Both Typeable _) $proxy')]|]+ Nothing -> [|[]|]+ _ -> examineSplice [||[]||]+ _ -> do+ reportWarning "discoverInstances called on 'reifyInstances' somehow returned something that wasn't a type class instance."+ examineSplice [||[]||]
+ test/Spec/HTree/Traverse.hs view
@@ -0,0 +1,15 @@+module Spec.HTree.Traverse (spec) where++import Data.Functor.Const (Const (Const))+import Data.HTree.Tree (HTree, hctraverse)+import Spec.HTree.Fixtures (ex, exShown, unI, type Ex)+import Spec.HTree.Helpers (forgetHTree)+import Test.Hspec (Spec, describe, it)++spec :: Spec+spec = do+ describe "use hctraverse" $ do+ it "yields the same result as expected" $ do+ let traversed :: Maybe (HTree (Const String) Ex)+ traversed = hctraverse @Show (Just . Const . show . unI) ex+ Just `traverse` exShown == (forgetHTree <$> traversed)