42 lines
1.2 KiB
Plaintext
42 lines
1.2 KiB
Plaintext
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module Lists where
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foreign import kind TList
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foreign import data TNil :: TList
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foreign import data TCons :: Type -> TList -> TList
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data TLProxy (tlist :: TList) = TLProxy
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foreign import kind RList
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foreign import data RNil :: RList
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foreign import data RCons :: #Type -> RList -> RList
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data RLProxy (tlist :: RList) = RLProxy
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infixr 6 type RCons as :
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-- | Check if a rlist contains a row
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class InList (t :: #Type) (list :: RList)
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instance inListFirst :: InList t (t : rest)
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else instance inListLater :: InList t tail => InList t (head : tail)
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-- | Remove an element from a list
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class Without (t :: #Type) (list :: RList) (remaining :: RList) | t list -> remaining
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instance withoutNil :: Without a RNil RNil
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else instance withoutHead :: Without a (RCons a tail) tail
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else instance withoutCons :: Without a tail remaining => Without a (RCons head tail) (RCons head remaining)
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-- | Break up function into it's components
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class MatchArrow t (arguments :: TList) return
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| t -> arguments return
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, arguments return -> t
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, arguments t -> return
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instance matchArrowRec
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:: MatchArrow to arguments return
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=> MatchArrow (from -> to) (TCons from arguments) return
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else instance matchArrowGeneral :: MatchArrow t TNil t
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