X-Git-Url: http://git.cielonegro.org/gitweb.cgi?a=blobdiff_plain;f=Data%2FHList%2FPrelude.hs;h=dc33147be63c7de93cc58dae3df25d723c3b680b;hb=2787678974b80d73e91b49b6b7c5469c6eb5ac1e;hp=3eb7e81cc37e80809878498b610dc86ee15b772a;hpb=4611522487b382b839a53e75e3feb2aac8764074;p=hs-rrdtool.git

diff --git a/Data/HList/Prelude.hs b/Data/HList/Prelude.hs
index 3eb7e81..dc33147 100644
--- a/Data/HList/Prelude.hs
+++ b/Data/HList/Prelude.hs
@@ -1,10 +1,15 @@
-{-# LANGUAGE DeriveDataTypeable,
-             FlexibleContexts,
-             FlexibleInstances,
-             MultiParamTypeClasses,
-             TypeFamilies,
-             TypeOperators,
-             UndecidableInstances
+{- -*- coding: utf-8 -*- -}
+{-# LANGUAGE
+  DeriveDataTypeable,
+  EmptyDataDecls,
+  FlexibleContexts,
+  FlexibleInstances,
+  FunctionalDependencies,
+  MultiParamTypeClasses,
+  OverlappingInstances,
+  TypeFamilies,
+  TypeOperators,
+  UndecidableInstances
   #-}
 module Data.HList.Prelude
     ( HList
@@ -15,22 +20,36 @@ module Data.HList.Prelude
     , HCons(..)
     , hCons
 
-    , HExtendable(..)
-    , HAppendable(..)
+    , HExtendT(..)
+    , HAppendT(..)
 
-    , Applyable(..)
-    , Applyable2(..)
+    , ApplyT(..)
+    , Apply2T(..)
 
     , Id(..)
-    , ApplyHAppend(..)
-
-    , HFoldrable(..)
-    , HConcatable(..)
-    , HMappable(..)
+    , HAppendA(..)
+
+    , HFoldrT(..)
+    , HConcatT(..)
+    , HMapT(..)
+
+    , HAll
+    , HLength
+
+    , Fail
+    , TypeFound
+    , TypeNotFound
+    , HOccursMany(..)
+    , HOccursMany1(..)
+    , HOccursOpt(..)
+    , HOccurs(..)
+    , HOccursNot(..)
     )
     where
 
 import Data.Typeable
+import Types.Data.Bool
+import Types.Data.Num hiding ((:*:))
 
 
 -- HList
@@ -56,100 +75,264 @@ instance HList l => HList (HCons e l)
 hCons :: HList l => e -> l -> HCons e l
 hCons = HCons
 
--- HExtendable
-infixr 2 :*:
-infixr 2 .*.
+-- HExtendT
+infixr 2 :&:
+infixr 2 .&.
 
-class HExtendable e l where
-    type e :*: l
-    (.*.) :: e -> l -> e :*: l
+class HExtendT e l where
+    type e :&: l
+    (.&.) :: e -> l -> e :&: l
 
-instance HExtendable e HNil where
-    type e :*: HNil = HCons e HNil
-    e .*. nil = hCons e nil
+instance HExtendT e HNil where
+    type e :&: HNil = HCons e HNil
+    e .&. nil = hCons e nil
 
-instance HList l => HExtendable e (HCons e' l) where
-    type e :*: HCons e' l = HCons e (HCons e' l)
-    e .*. HCons e' l = hCons e (hCons e' l)
+instance HList l => HExtendT e (HCons e' l) where
+    type e :&: HCons e' l = HCons e (HCons e' l)
+    e .&. HCons e' l = hCons e (hCons e' l)
 
--- HAppendable
+-- HAppendT
 infixr 1 :++:
 infixr 1 .++.
 
-class HAppendable l l' where
+class HAppendT l l' where
     type l :++: l'
     (.++.) :: l -> l' -> l :++: l'
 
-instance HList l => HAppendable HNil l where
+instance HList l => HAppendT HNil l where
     type HNil :++: l = l
     _ .++. l = l
 
 instance ( HList (l :++: l')
-         , HAppendable l l'
-         ) => HAppendable (HCons e l) l' where
+         , HAppendT l l'
+         ) => HAppendT (HCons e l) l' where
     type HCons e l :++: l' = HCons e (l :++: l')
     (HCons e l) .++. l' = hCons e (l .++. l')
 
--- Applyable
-class Applyable f a where
+-- ApplyT
+class ApplyT f a where
     type Apply f a
     apply :: f -> a -> Apply f a
+    apply _ _ = undefined
 
--- Applyable2
-class Applyable2 f a b where
+-- Apply2T
+class Apply2T f a b where
     type Apply2 f a b
     apply2 :: f -> a -> b -> Apply2 f a b
+    apply2 _ _ _ = undefined
 
 -- Id
 data Id = Id
 
-instance Applyable Id a where
+instance ApplyT Id a where
     type Apply Id a = a
     apply _ a = a
 
--- ApplyHAppend
-data ApplyHAppend = ApplyHAppend
+-- HAppendA
+data HAppendA = HAppendA
 
-instance HAppendable a b => Applyable2 ApplyHAppend a b where
-    type Apply2 ApplyHAppend a b = a :++: b
+instance HAppendT a b => Apply2T HAppendA a b where
+    type Apply2 HAppendA a b = a :++: b
     apply2 _ a b = a .++. b
 
--- HFoldrable
-class HFoldrable f v l where
+-- HFoldrT
+class HFoldrT f v l where
     type HFoldr f v l
     hFoldr :: f -> v -> l -> HFoldr f v l
 
-instance HFoldrable f v HNil where
+instance HFoldrT f v HNil where
     type HFoldr f v HNil = v
     hFoldr _ v _ = v
 
-instance ( HFoldrable f v l
-         , Applyable2 f e (HFoldr f v l)
-         ) => HFoldrable f v (HCons e l) where
+instance ( HFoldrT f v l
+         , Apply2T f e (HFoldr f v l)
+         ) => HFoldrT f v (HCons e l) where
     type HFoldr f v (HCons e l) = Apply2 f e (HFoldr f v l)
     hFoldr f v (HCons e l) = apply2 f e (hFoldr f v l)
 
--- HConcatable
-class HConcatable ls where
+-- HConcatT
+class HConcatT ls where
     type HConcat ls
     hConcat :: ls -> HConcat ls
 
-instance HFoldrable ApplyHAppend HNil ls => HConcatable ls where
-    type HConcat ls = HFoldr ApplyHAppend HNil ls
-    hConcat ls = hFoldr ApplyHAppend hNil ls
+instance HFoldrT HAppendA HNil ls => HConcatT ls where
+    type HConcat ls = HFoldr HAppendA HNil ls
+    hConcat ls = hFoldr HAppendA hNil ls
 
--- HMappable
-class HMappable f l where
+-- HMapT
+class HMapT f l where
     type HMap f l
     hMap :: f -> l -> HMap f l
 
-instance HMappable f HNil where
+instance HMapT f HNil where
     type HMap f HNil = HNil
     hMap _ _ = hNil
 
-instance ( Applyable f x
-         , HMappable f xs
+instance ( ApplyT f x
+         , HMapT f xs
          , HList (HMap f xs)
-         ) => HMappable f (HCons x xs) where
+         ) => HMapT f (HCons x xs) where
     type HMap f (HCons x xs) = HCons (Apply f x) (HMap f xs)
     hMap f (HCons x xs) = hCons (apply f x) (hMap f xs)
+
+-- HAll
+type family HAll f l
+type instance HAll f HNil         = True
+type instance HAll f (HCons x xs) = If (Apply f x) (HAll f xs) False
+
+-- HLength
+type family HLength l
+type instance HLength HNil        = D0
+type instance HLength (HCons e l) = Succ (HLength l)
+
+-- Fail
+class Fail a
+
+-- HOccursMany (zero or more)
+class HOccursMany e l where
+    hOccursMany :: l -> [e]
+
+instance HOccursMany e HNil where
+    hOccursMany _ = []
+
+instance ( HList l
+         , HOccursMany e l
+         )
+    => HOccursMany e (HCons e l)
+    where
+      hOccursMany (HCons e l) = e : hOccursMany l
+
+instance ( HList l
+         , HOccursMany e l
+         )
+    => HOccursMany e (HCons e' l)
+    where
+      hOccursMany (HCons _ l) = hOccursMany l
+
+-- HOccursMany1 (one or more)
+class HOccursMany1 e l where
+    hOccursMany1 :: l -> [e]
+
+instance Fail (TypeNotFound e) => HOccursMany1 e HNil where
+    hOccursMany1 _ = undefined
+
+instance ( HList l
+         , HOccursMany e l
+         )
+    => HOccursMany1 e (HCons e l)
+    where
+      hOccursMany1 (HCons e l) = e : hOccursMany l
+
+instance ( HList l
+         , HOccursMany1 e l
+         )
+    => HOccursMany1 e (HCons e' l)
+    where
+      hOccursMany1 (HCons _ l) = hOccursMany1 l
+
+-- HOccursOpt (zero or one)
+class HOccursOpt e l where
+    hOccursOpt :: l -> Maybe e
+
+instance HOccursOpt e HNil where
+    hOccursOpt _ = Nothing
+
+instance HOccursNot e l => HOccursOpt e (HCons e l) where
+    hOccursOpt (HCons e _) = Just e
+
+instance HOccursOpt e l => HOccursOpt e (HCons e' l) where
+    hOccursOpt (HCons _ l) = hOccursOpt l
+
+-- HOccurs (one)
+class HOccurs e l where
+    hOccurs :: l -> e
+
+data TypeNotFound e
+
+instance Fail (TypeNotFound e) => HOccurs e HNil
+    where
+      hOccurs = undefined
+
+instance ( HList l
+         , HOccursNot e l
+         )
+    => HOccurs e (HCons e l)
+    where
+      hOccurs (HCons e _) = e
+
+instance ( HList l
+         , HOccurs e l
+         )
+    => HOccurs e (HCons e' l)
+    where
+      hOccurs (HCons _ l) = hOccurs l
+
+-- HOccursNot (zero)
+data     TypeFound e
+class    HOccursNot e l
+instance HOccursNot e HNil
+instance Fail (TypeFound e) => HOccursNot e (HCons e  l)
+instance HOccursNot e l     => HOccursNot e (HCons e' l)
+
+{-
+{-
+"Strongly Typed Heterogeneous Collections"
+   — August 26, 2004
+       Oleg Kiselyov
+       Ralf Lämmel
+       Keean Schupke
+==========================
+9 By chance or by design? 
+
+We will now discuss the issues surrounding the definition of type
+equality, inequality, and unification — and give implementations
+differing in simplicity, genericity, and portability.
+
+We define the class TypeEq x y b for type equality. The class relates
+two types x and y to the type HTrue in case the two types are equal;
+otherwise, the types are related to HFalse. We should point out
+however groundness issues. If TypeEq is to return HTrue, the types
+must be ground; TypeEq can return HFalse even for unground types,
+provided they are instantiated enough to determine that they are not
+equal. So, TypeEq is total for ground types, and partial for unground
+types. We also define the class TypeCast x y: a constraint that holds
+only if the two types x and y are unifiable. Regarding groundness of x
+and y, the class TypeCast is less restricted than TypeEq. That is,
+TypeCast x y succeeds even for unground types x and y in case they can
+be made equal through unification. TypeEq and TypeCast are related to
+each other as fol- lows. Whenever TypeEq succeeds with HTrue, TypeCast
+succeeds as well. Whenever TypeEq succeeds with HFalse, TypeCast
+fails.  But for unground types, when TypeCast succeeds, TypeEq might
+fail. So the two complement each other for unground types. Also,
+TypeEq is a partial predicate, while TypeCast is a relation. That’s
+why both are useful.
+ -}
+class    TypeEq x y b | x y -> b
+instance TypeEq x x True
+instance TypeCast False b =>
+         TypeEq x y b
+
+class TypeCast a b | a -> b, b -> a
+    where
+      typeCast :: a -> b
+
+class TypeCast' t a b | t a -> b, t b -> a
+    where
+      typeCast' :: t -> a -> b
+
+class TypeCast'' t a b | t a -> b, t b -> a
+    where
+      typeCast'' :: t -> a -> b
+
+instance TypeCast' () a b => TypeCast a b
+    where
+      typeCast x = typeCast' () x
+
+instance TypeCast'' t a b => TypeCast' t a b
+    where
+      typeCast' = typeCast''
+
+instance TypeCast'' () a a
+    where
+      typeCast'' _ x = x
+-}
\ No newline at end of file