module Control.Egison.Match (
matchAll,
match,
matchAllDFS,
matchDFS,
) where
import Prelude hiding (mappend)
import Control.Egison.Core
import Unsafe.Coerce
import Data.Type.Equality
{-# INLINE matchAll #-}
matchAll :: (Matcher m a) => a -> m -> [MatchClause a m b] -> [b]
matchAll tgt m = foldr go []
where
go (MatchClause pat f) acc =
let results = processMStatesAll [[MState HNil (MCons (MAtom pat m tgt) MNil)]] in
map f results ++ acc
{-# INLINE match #-}
match :: (Matcher m a) => a -> m -> [MatchClause a m b] -> b
match tgt m cs = head $ matchAll tgt m cs
{-# INLINE matchAllDFS #-}
matchAllDFS :: (Matcher m a) => a -> m -> [MatchClause a m b] -> [b]
matchAllDFS tgt m = foldr go []
where
go (MatchClause pat f) acc =
let results = processMStatesAllDFS [MState HNil (MCons (MAtom pat m tgt) MNil)] in
map f results ++ acc
{-# INLINE matchDFS #-}
matchDFS :: (Matcher m a) => a -> m -> [MatchClause a m b] -> b
matchDFS tgt m cs = head $ matchAllDFS tgt m cs
processMStatesAllDFS :: [MState vs] -> [HList vs]
processMStatesAllDFS [] = []
processMStatesAllDFS (MState rs MNil:ms) = rs:(processMStatesAllDFS ms)
processMStatesAllDFS (mstate:ms) = processMStatesAllDFS $ (processMState mstate) ++ ms
processMStatesAll :: [[MState vs]] -> [HList vs]
processMStatesAll [] = []
processMStatesAll streams = results ++ processMStatesAll streams'
where
(results, streams') = foldr processMStates ([], []) streams
processMStates :: [MState vs] -> ([HList vs], [[MState vs]]) -> ([HList vs], [[MState vs]])
processMStates [] (results, acc) = (results, acc)
processMStates (MState rs MNil:ms) (results, acc) = processMStates ms (rs:results, acc)
processMStates (mstate:ms) (results, acc) = (results, processMState mstate:ms:acc)
{-# INLINE processMState #-}
processMState :: MState vs -> [MState vs]
processMState (MState rs (MCons (MAtom pat m tgt) atoms)) =
case pat of
Pattern f ->
let matomss = f rs m tgt in
map (\newAtoms -> MState rs (mappend newAtoms atoms)) matomss
Wildcard -> [MState rs atoms]
PatVar _ -> case patVarProof rs (HCons tgt HNil) atoms of
Refl -> [MState (happend rs (HCons tgt HNil)) atoms]
AndPat p1 p2 ->
case (assocProof (MAtom p1 m tgt) (MAtom p2 m tgt)) of
Refl -> case (andPatProof (MAtom p1 m tgt) (MAtom p2 m tgt) atoms) of
Refl -> [MState rs (MCons (MAtom p1 m tgt) (MCons (MAtom p2 m tgt) $ atoms))]
OrPat p1 p2 ->
[MState rs (MCons (MAtom p1 m tgt) atoms), MState rs (MCons (MAtom p2 m tgt) atoms)]
NotPat p ->
[MState rs atoms | null $ processMStatesAllDFS [MState rs $ MCons (MAtom p m tgt) MNil]]
PredicatePat f -> [MState rs atoms | f rs tgt]
processMState (MState rs MNil) = undefined
{-# INLINE patVarProof #-}
patVarProof :: HList xs -> HList '[a] -> MList (xs :++: '[a]) ys -> ((xs :++: '[a]) :++: ys) :~: (xs :++: ('[a] :++: ys))
patVarProof HNil _ _ = Refl
patVarProof (HCons _ xs) ys zs = unsafeCoerce Refl
{-# INLINE andPatProof #-}
andPatProof :: MAtom ctx vs -> MAtom (ctx :++: vs) vs' -> MList (ctx :++: vs :++: vs') ys -> (ctx :++: ((vs :++: vs') :++: ys)) :~: (ctx :++: (vs :++: (vs' :++: ys)))
andPatProof _ _ _ = unsafeCoerce Refl
{-# INLINE assocProof #-}
assocProof :: MAtom ctx vs -> MAtom (ctx :++: vs) vs' -> (ctx :++: (vs :++: vs')) :~: ((ctx :++: vs) :++: vs')
assocProof _ _ = unsafeCoerce Refl