{-# LANGUAGE DataKinds #-}
{-# LANGUAGE GADTs #-}
module Control.Egison.Match (
matchAll,
match,
matchAllDFS,
matchDFS,
) where
import Control.Egison.Core
import Unsafe.Coerce
matchAll :: (Matcher m) => a -> m -> [MatchClause a m b] -> [b]
matchAll tgt m [] = []
matchAll tgt m ((MatchClause pat f):cs) =
let results = processMStatesAll [[MState HNil (MCons (MAtom pat m tgt) MNil)]] in
map f results ++ matchAll tgt m cs
match :: (Matcher m) => a -> m -> [MatchClause a m b] -> b
match tgt m cs = head $ matchAll tgt m cs
matchAllDFS :: (Matcher m) => a -> m -> [MatchClause a m b] -> [b]
matchAllDFS tgt m [] = []
matchAllDFS tgt m ((MatchClause pat f):cs) =
let results = processMStatesAllDFS [MState HNil (MCons (MAtom pat m tgt) MNil)] in
map f results ++ matchAllDFS tgt m cs
matchDFS :: (Matcher m) => 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 =
case extractMatches $ concatMap processMStates streams of
([], streams') -> processMStatesAll streams'
(results, streams') -> results ++ processMStatesAll streams'
extractMatches :: [[MState vs]] -> ([HList vs], [[MState vs]])
extractMatches = extractMatches' ([], [])
where
extractMatches' :: ([HList vs], [[MState vs]]) -> [[MState vs]] -> ([HList vs], [[MState vs]])
extractMatches' (xs, ys) [] = (reverse xs, reverse ys)
extractMatches' (xs, ys) ((MState rs MNil:[]):rest) = extractMatches' (rs:xs, ys) rest
extractMatches' (xs, ys) (stream:rest) = extractMatches' (xs, stream:ys) rest
processMStates :: [MState vs] -> [[MState vs]]
processMStates [] = []
processMStates (mstate:ms) = [processMState mstate, ms]
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 (MJoin newAtoms atoms)) matomss
Wildcard -> [MState rs atoms]
PatVar _ -> [unsafeCoerce $ MState (happend rs (HCons tgt HNil)) atoms]
AndPat p1 p2 ->
[unsafeCoerce $ MState rs (MCons (MAtom p1 m tgt) (MCons (MAtom p2 m tgt) $ unsafeCoerce 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 $ processMStatesAll [[MState rs $ MCons (MAtom p m tgt) MNil]]]
PredicatePat f -> [MState rs atoms | f rs tgt]
processMState (MState rs (MJoin MNil matoms2)) = processMState (MState rs matoms2)
processMState (MState rs (MJoin matoms1 matoms2)) =
let mstates = processMState (MState rs matoms1) in
map (\(MState rs' ms) -> unsafeCoerce $ MState rs' $ MJoin ms matoms2) mstates
processMState (MState rs MNil) = [MState rs MNil]