ref: 99944a78c8f19d35dd53f82161c671de3264f8d2
dir: /src/Text/ParserComb.hs/
-- Copyright 2023 Lennart Augustsson
-- See LICENSE file for full license.
{-# OPTIONS_GHC -Wno-type-defaults #-}
{-# LANGUAGE FunctionalDependencies #-}
module Text.ParserComb(
Prsr, runPrsr,
satisfy, satisfyM,
satisfyMany,
choice,
many, emany, optional, eoptional,
some, esome,
esepBy, sepBy1, esepBy1,
esepEndBy, esepEndBy1,
(<?>), (<|<),
--notFollowedBy,
--lookAhead,
nextToken,
LastFail(..),
TokenMachine(..),
mapTokenState,
) where
import Prelude(); import MHSPrelude
import Control.Applicative
import Control.Monad
data LastFail t
= LastFail Int [t] [String]
deriving (Show)
maxInt :: Int
maxInt = 1000000000
noFail :: forall t . LastFail t
noFail = LastFail maxInt [] []
longest :: forall t . LastFail t -> LastFail t -> LastFail t
longest lf1@(LastFail l1 t1 x1) lf2@(LastFail l2 _ x2) =
if l1 < l2 then
lf1
else if l2 < l1 then
lf2
else
LastFail l1 t1 (x1 ++ x2)
longests :: forall t . [LastFail t] -> LastFail t
longests xs = foldl1 longest xs
class TokenMachine tm t | tm -> t where
tmNextToken :: tm -> (t, tm)
tmRawTokens :: tm -> [t]
tmLeft :: forall tm t . TokenMachine tm t => tm -> Int
tmLeft = length . tmRawTokens
firstToken :: forall tm t . TokenMachine tm t => tm -> [t]
firstToken tm =
case tmNextToken tm of
(t, _) -> [t]
data Res tm t a = Many [(a, tm)] (LastFail t)
--deriving (Show)
data Prsr tm t a = P (tm -> Res tm t a)
--instance Show (Prsr s t a) where show _ = "<<Prsr>>"
runP :: forall tm t a . Prsr tm t a -> (tm -> Res tm t a)
runP (P p) = p
mapTokenState :: forall tm t . (tm -> tm) -> Prsr tm t ()
mapTokenState f = P (\ tm -> Many [((), f tm)] noFail)
instance forall tm t . Functor (Prsr tm t) where
fmap f p = P $ \ t ->
case runP p t of
Many aus lf -> Many [ (f a, u) | (a, u) <- aus ] lf
instance forall tm t . Applicative (Prsr tm t) where
pure a = P $ \ t -> Many [(a, t)] noFail
(<*>) = ap
(*>) p k = p >>= \ _ -> k
instance forall tm t . Monad (Prsr tm t) where
(>>=) p k = P $ \ t ->
case runP p t of
Many aus plf ->
let ms = map (\ (a, u) -> runP (k a) u) aus
lfs = map (\ (Many _ lf) -> lf) ms
rrs = [ r | Many rs _ <- ms, r <- rs ]
in Many rrs (longests (plf : lfs))
return = pure
instance forall t tm . TokenMachine tm t => MonadFail (Prsr tm t) where
fail m = P $ \ ts -> Many [] (LastFail (tmLeft ts) (firstToken ts) [m])
instance forall t tm . TokenMachine tm t => Alternative (Prsr tm t) where
empty = P $ \ ts -> Many [] (LastFail (tmLeft ts) (firstToken ts) ["empty"])
(<|>) p q = P $ \ t ->
case runP p t of
Many a lfa ->
case runP q t of
Many b lfb -> Many (a ++ b) (longest lfa lfb)
-- Left biased choice
infixl 3 <|<
(<|<) :: forall tm t a . Prsr tm t a -> Prsr tm t a -> Prsr tm t a
(<|<) p q = P $ \ t ->
case runP p t of
Many [] lfa ->
case runP q t of
Many b lfb -> Many b (longest lfa lfb)
r -> r
satisfy :: forall tm t . TokenMachine tm t => String -> (t -> Bool) -> Prsr tm t t
satisfy msg f = P $ \ acs ->
case tmNextToken acs of
r@(c, _) | f c -> Many [r] noFail
_ -> Many [] (LastFail (tmLeft acs) (firstToken acs) [msg])
satisfyM :: forall tm t a . TokenMachine tm t => String -> (t -> Maybe a) -> Prsr tm t a
satisfyM msg f = P $ \ acs ->
case tmNextToken acs of
(c, cs) | Just a <- f c -> Many [(a, cs)] noFail
_ -> Many [] (LastFail (tmLeft acs) (firstToken acs) [msg])
satisfyMany :: forall tm t . TokenMachine tm t => (t -> Bool) -> Prsr tm t [t]
satisfyMany f = P $ loop []
where loop res acs =
case tmNextToken acs of
(c, cs) | f c -> loop (c:res) cs
| otherwise -> Many [(reverse res, acs)] noFail
infixl 9 <?>
(<?>) :: forall tm t a . Prsr tm t a -> String -> Prsr tm t a
(<?>) p e = P $ \ t ->
-- trace ("<?> " ++ show e) $
case runP p t of
Many rs (LastFail l ts _) -> Many rs (LastFail l ts [e])
{-
lookAhead :: forall tm t a . TokenMachine tm t => Prsr tm t a -> Prsr tm t ()
lookAhead p = P $ \ t ->
case runP p t of
Many [] (LastFail l ts xs) -> Many [] (LastFail l (take 1 ts) xs)
_ -> Many [((), t)] noFail
-}
nextToken :: forall tm t . TokenMachine tm t => Prsr tm t t
nextToken = P $ \ cs ->
case tmNextToken cs of
(c, _) -> Many [(c, cs)] noFail
{-
eof :: forall tm t . TokenMachine tm t => Prsr tm t ()
eof = P $ \ t@(cs, _) ->
case tmNextToken cs of
Nothing -> Many [((), t)] noFail
Just _ -> Many [] (LastFail (tmLeft cs) (firstToken cs) ["eof"])
-}
{-
notFollowedBy :: forall t a . Prsr t a -> Prsr t ()
notFollowedBy p = P $ \ t@(ts,_) ->
case runP p t of
Many [] _ -> Many [((), t)] noFail
_ -> Many [] (LastFail (length ts) (take 1 ts) ["!"])
-}
runPrsr :: forall tm t a . --X(Show a, Show s) =>
Prsr tm t a -> tm -> Either (LastFail t) [a]
runPrsr (P p) f =
case p f of
Many [] lf -> Left lf
Many xs _ -> Right [a | (a, _) <- xs ]
-------------------------------
emany :: forall tm t a . Prsr tm t a -> Prsr tm t [a]
emany p = esome p <|< pure []
esome :: forall tm t a . Prsr tm t a -> Prsr tm t [a]
esome p = (:) <$> p <*> emany p
eoptional :: forall tm t a . Prsr tm t a -> Prsr tm t (Maybe a)
eoptional p = (Just <$> p) <|< pure Nothing
choice :: forall tm t a . TokenMachine tm t => [Prsr tm t a] -> Prsr tm t a
choice [] = empty
choice ps = foldr1 (<|>) ps
sepBy1 :: forall tm t a sep . TokenMachine tm t => Prsr tm t a -> Prsr tm t sep -> Prsr tm t [a]
sepBy1 p sep = (:) <$> p <*> many (sep *> p)
esepBy1 :: forall tm t a sep . Prsr tm t a -> Prsr tm t sep -> Prsr tm t [a]
esepBy1 p sep = (:) <$> p <*> emany (sep *> p)
esepBy :: forall tm t a sep . Prsr tm t a -> Prsr tm t sep -> Prsr tm t [a]
esepBy p sep = esepBy1 p sep <|< pure []
esepEndBy :: forall tm t a sep . Prsr tm t a -> Prsr tm t sep -> Prsr tm t [a]
esepEndBy p sep = esepEndBy1 p sep <|< pure []
esepEndBy1 :: forall tm t a sep . Prsr tm t a -> Prsr tm t sep -> Prsr tm t [a]
esepEndBy1 p sep = (:) <$> p <*> ((sep *> esepEndBy p sep) <|< pure [])