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implementation module Sil.Util.Parser
import StdList
import StdOverloaded
import Control.Applicative
import Control.Monad
import Data.Error
from Data.Func import $
import Data.Functor
import Data.List
import Sil.Error
instance Functor (Parser a) where
fmap f m = liftM f m
instance Applicative (Parser a) where
pure a = Parser \i -> (Ok a, i)
(<*>) sf p = ap sf p
instance Monad (Parser a) where
bind p f = Parser \i -> case runParser p i of
(Ok r, rest) -> runParser (f r) rest
(Error e, _) -> (Error e, i)
instance Alternative (Parser a) where
empty = Parser \i -> (Error $ UnknownError "empty in Parser", i)
(<|>) p1 p2 = Parser \i -> case runParser p1 i of
(Ok r, rest) -> (Ok r, rest)
(Error e1, rest) -> case runParser p2 i of
(Error e2, rest) -> (Error e2, i)
(Ok r, rest) -> (Ok r, rest)
instance name String where name s = s
runParser :: (Parser a b) [a] -> (MaybeError Error b, [a])
runParser (Parser f) i = f i
(<?>) :: (Parser a b) Error -> Parser a b
(<?>) p e = Parser \i -> case runParser p i of
(Error _, rest) -> (Error e, rest)
o -> o
fail :: Parser a b
fail = empty
top :: Parser a a
top = Parser \i -> case i of
[] = (Error $ UnknownError "top in Parser failed", [])
[x:xs] = (Ok x, xs)
peek :: Parser a a
peek = Parser \i -> case i of
[] = (Error $ UnknownError "peek in Parser failed", [])
[x:xs] = (Ok x, [x:xs])
satisfy :: (a -> Bool) -> Parser a a
satisfy f = top >>= \r -> if (f r) (pure r) fail
check :: (a -> Bool) -> Parser a a
check f = peek >>= \r -> if (f r) (pure r) fail
(until) infix 2 :: (Parser a b) (Parser a c) -> Parser a [b]
(until) p guard = try $ until` p guard []
where
until` :: (Parser a b) (Parser a c) [b] -> Parser a [b]
until` p guard acc = Parser \i -> case runParser guard i of
(Ok _, rest) -> (Ok acc, rest)
(Error _, _) -> case runParser p i of
(Ok r, rest) -> runParser (until` p guard [r:acc]) rest
(Error e, _) -> (Error e, i)
try :: (Parser a b) -> Parser a b
try p = Parser \i -> case runParser p i of
(Error e, _) -> (Error e, i)
(Ok r, rest) -> (Ok r, rest)
item :: a -> Parser a a | ==, name a
item a = satisfy ((==) a) <?> P_Expected (name a)
list :: [a] -> Parser a [a] | ==, name a
list as = mapM item as
seplist :: a (Parser a b) -> Parser a [b] | ==, name a
seplist sep p = liftM2 (\es e-> es ++ [e]) (some (p <* item sep)) p
<|> liftM pure p
<|> pure empty
eof :: Parser a ()
eof = Parser \i -> case i of
[] = (Ok (), [])
_ = (Error $ P_Expected "eof", i)
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