Commit 9eb04a6b authored by md9ms's avatar md9ms
Browse files

Switch from parsec parsing to ReadP parsing

Note that this uses a locally hacked ReadP (Compat.ReadP) that's
been altered to be H98 compatible.
parent 0cf06db1
-----------------------------------------------------------------------------
-- |
-- Module : Text.ParserCombinators.ReadP
-- Copyright : (c) The University of Glasgow 2002
-- License : BSD-style (see the file libraries/base/LICENSE)
--
-- Maintainer : libraries@haskell.org
-- Stability : provisional
-- Portability : non-portable (local universal quantification)
--
-- This is a library of parser combinators, originally written by Koen Claessen.
-- It parses all alternatives in parallel, so it never keeps hold of
-- the beginning of the input string, a common source of space leaks with
-- other parsers. The '(+++)' choice combinator is genuinely commutative;
-- it makes no difference which branch is \"shorter\".
--
-- See also Koen's paper /Parallel Parsing Processes/
-- (<http://www.cs.chalmers.se/~koen/publications.html>).
--
-- This version of ReadP has been locally hacked to make it H98, by
-- Martin Sjögren <msjogren@gmail.com>
-----------------------------------------------------------------------------
module Compat.ReadP
(
-- * The 'ReadP' type
ReadP, -- :: * -> *; instance Functor, Monad, MonadPlus
-- * Primitive operations
get, -- :: ReadP Char
look, -- :: ReadP String
(+++), -- :: ReadP a -> ReadP a -> ReadP a
(<++), -- :: ReadP a -> ReadP a -> ReadP a
gather, -- :: ReadP a -> ReadP (String, a)
-- * Other operations
pfail, -- :: ReadP a
satisfy, -- :: (Char -> Bool) -> ReadP Char
char, -- :: Char -> ReadP Char
string, -- :: String -> ReadP String
munch, -- :: (Char -> Bool) -> ReadP String
munch1, -- :: (Char -> Bool) -> ReadP String
skipSpaces, -- :: ReadP ()
choice, -- :: [ReadP a] -> ReadP a
count, -- :: Int -> ReadP a -> ReadP [a]
between, -- :: ReadP open -> ReadP close -> ReadP a -> ReadP a
option, -- :: a -> ReadP a -> ReadP a
optional, -- :: ReadP a -> ReadP ()
many, -- :: ReadP a -> ReadP [a]
many1, -- :: ReadP a -> ReadP [a]
skipMany, -- :: ReadP a -> ReadP ()
skipMany1, -- :: ReadP a -> ReadP ()
sepBy, -- :: ReadP a -> ReadP sep -> ReadP [a]
sepBy1, -- :: ReadP a -> ReadP sep -> ReadP [a]
endBy, -- :: ReadP a -> ReadP sep -> ReadP [a]
endBy1, -- :: ReadP a -> ReadP sep -> ReadP [a]
chainr, -- :: ReadP a -> ReadP (a -> a -> a) -> a -> ReadP a
chainl, -- :: ReadP a -> ReadP (a -> a -> a) -> a -> ReadP a
chainl1, -- :: ReadP a -> ReadP (a -> a -> a) -> ReadP a
chainr1, -- :: ReadP a -> ReadP (a -> a -> a) -> ReadP a
manyTill, -- :: ReadP a -> ReadP end -> ReadP [a]
-- * Running a parser
ReadS, -- :: *; = String -> [(a,String)]
readP_to_S, -- :: ReadP a -> ReadS a
readS_to_P, -- :: ReadS a -> ReadP a
-- * Properties
-- $properties
)
where
import Control.Monad( MonadPlus(..), liftM2 )
import Data.Char (isSpace)
infixr 5 +++, <++
-- ---------------------------------------------------------------------------
-- The P type
-- is representation type -- should be kept abstract
data P s a
= Get (s -> P s a)
| Look ([s] -> P s a)
| Fail
| Result a (P s a)
| Final [(a,[s])] -- invariant: list is non-empty!
-- Monad, MonadPlus
instance Monad (P s) where
return x = Result x Fail
(Get f) >>= k = Get (\c -> f c >>= k)
(Look f) >>= k = Look (\s -> f s >>= k)
Fail >>= k = Fail
(Result x p) >>= k = k x `mplus` (p >>= k)
(Final r) >>= k = final [ys' | (x,s) <- r, ys' <- run (k x) s]
fail _ = Fail
instance MonadPlus (P s) where
mzero = Fail
-- most common case: two gets are combined
Get f1 `mplus` Get f2 = Get (\c -> f1 c `mplus` f2 c)
-- results are delivered as soon as possible
Result x p `mplus` q = Result x (p `mplus` q)
p `mplus` Result x q = Result x (p `mplus` q)
-- fail disappears
Fail `mplus` p = p
p `mplus` Fail = p
-- two finals are combined
-- final + look becomes one look and one final (=optimization)
-- final + sthg else becomes one look and one final
Final r `mplus` Final t = Final (r ++ t)
Final r `mplus` Look f = Look (\s -> Final (r ++ run (f s) s))
Final r `mplus` p = Look (\s -> Final (r ++ run p s))
Look f `mplus` Final r = Look (\s -> Final (run (f s) s ++ r))
p `mplus` Final r = Look (\s -> Final (run p s ++ r))
-- two looks are combined (=optimization)
-- look + sthg else floats upwards
Look f `mplus` Look g = Look (\s -> f s `mplus` g s)
Look f `mplus` p = Look (\s -> f s `mplus` p)
p `mplus` Look f = Look (\s -> p `mplus` f s)
-- ---------------------------------------------------------------------------
-- The ReadP type
newtype Parser r s a = R ((a -> P s r) -> P s r)
type ReadP r a = Parser r Char a
-- Functor, Monad, MonadPlus
instance Functor (Parser r s) where
fmap h (R f) = R (\k -> f (k . h))
instance Monad (Parser r s) where
return x = R (\k -> k x)
fail _ = R (\_ -> Fail)
R m >>= f = R (\k -> m (\a -> let R m' = f a in m' k))
instance MonadPlus (Parser r s) where
mzero = pfail
mplus = (+++)
-- ---------------------------------------------------------------------------
-- Operations over P
final :: [(a,[s])] -> P s a
-- Maintains invariant for Final constructor
final [] = Fail
final r = Final r
--run :: P s a -> ReadS a
run (Get f) (c:s) = run (f c) s
run (Look f) s = run (f s) s
run (Result x p) s = (x,s) : run p s
run (Final r) _ = r
run _ _ = []
-- ---------------------------------------------------------------------------
-- Operations over ReadP
--get :: ReadP Char
-- ^ Consumes and returns the next character.
-- Fails if there is no input left.
get = R Get
--look :: ReadP String
-- ^ Look-ahead: returns the part of the input that is left, without
-- consuming it.
look = R Look
--pfail :: ReadP a
-- ^ Always fails.
pfail = R (\_ -> Fail)
--(+++) :: ReadP a -> ReadP a -> ReadP a
-- ^ Symmetric choice.
R f1 +++ R f2 = R (\k -> f1 k `mplus` f2 k)
--(<++) :: ReadP a -> ReadP a -> ReadP a
-- ^ Local, exclusive, left-biased choice: If left parser
-- locally produces any result at all, then right parser is
-- not used.
R f <++ q =
do s <- look
probe (f return) s 0
where
probe (Get f) (c:s) n = probe (f c) s (n+1)
probe (Look f) s n = probe (f s) s n
probe p@(Result _ _) _ n = discard n >> R (p >>=)
probe (Final r) _ _ = R (Final r >>=)
probe _ _ _ = q
discard 0 = return ()
discard n = get >> discard (n-1)
--gather :: ReadP a -> ReadP (String, a)
-- ^ Transforms a parser into one that does the same, but
-- in addition returns the exact characters read.
-- IMPORTANT NOTE: 'gather' gives a runtime error if its first argument
-- is built using any occurrences of readS_to_P.
gather (R m) =
R (\k -> gath id (m (\a -> return (\s -> k (s,a)))))
where
gath l (Get f) = Get (\c -> gath (l.(c:)) (f c))
gath l Fail = Fail
gath l (Look f) = Look (\s -> gath l (f s))
gath l (Result k p) = k (l []) `mplus` gath l p
gath l (Final r) = error "do not use readS_to_P in gather!"
-- ---------------------------------------------------------------------------
-- Derived operations
--satisfy :: (Char -> Bool) -> ReadP Char
-- ^ Consumes and returns the next character, if it satisfies the
-- specified predicate.
satisfy p = do c <- get; if p c then return c else pfail
--char :: Char -> ReadP Char
-- ^ Parses and returns the specified character.
char c = satisfy (c ==)
--string :: String -> ReadP String
-- ^ Parses and returns the specified string.
string this = do s <- look; scan this s
where
scan [] _ = do return this
scan (x:xs) (y:ys) | x == y = do get; scan xs ys
scan _ _ = do pfail
--munch :: (Char -> Bool) -> ReadP String
-- ^ Parses the first zero or more characters satisfying the predicate.
munch p =
do s <- look
scan s
where
scan (c:cs) | p c = do get; s <- scan cs; return (c:s)
scan _ = do return ""
--munch1 :: (Char -> Bool) -> ReadP String
-- ^ Parses the first one or more characters satisfying the predicate.
munch1 p =
do c <- get
if p c then do s <- munch p; return (c:s) else pfail
--choice :: [ReadP a] -> ReadP a
-- ^ Combines all parsers in the specified list.
choice [] = pfail
choice [p] = p
choice (p:ps) = p +++ choice ps
--skipSpaces :: ReadP ()
-- ^ Skips all whitespace.
skipSpaces =
do s <- look
skip s
where
skip (c:s) | isSpace c = do get; skip s
skip _ = do return ()
--count :: Int -> ReadP a -> ReadP [a]
-- ^ @ count n p @ parses @n@ occurrences of @p@ in sequence. A list of
-- results is returned.
count n p = sequence (replicate n p)
--between :: ReadP open -> ReadP close -> ReadP a -> ReadP a
-- ^ @ between open close p @ parses @open@, followed by @p@ and finally
-- @close@. Only the value of @p@ is returned.
between open close p = do open
x <- p
close
return x
--option :: a -> ReadP a -> ReadP a
-- ^ @option x p@ will either parse @p@ or return @x@ without consuming
-- any input.
option x p = p +++ return x
--optional :: ReadP a -> ReadP ()
-- ^ @optional p@ optionally parses @p@ and always returns @()@.
optional p = (p >> return ()) +++ return ()
--many :: ReadP a -> ReadP [a]
-- ^ Parses zero or more occurrences of the given parser.
many p = return [] +++ many1 p
--many1 :: ReadP a -> ReadP [a]
-- ^ Parses one or more occurrences of the given parser.
many1 p = liftM2 (:) p (many p)
--skipMany :: ReadP a -> ReadP ()
-- ^ Like 'many', but discards the result.
skipMany p = many p >> return ()
--skipMany1 :: ReadP a -> ReadP ()
-- ^ Like 'many1', but discards the result.
skipMany1 p = p >> skipMany p
--sepBy :: ReadP a -> ReadP sep -> ReadP [a]
-- ^ @sepBy p sep@ parses zero or more occurrences of @p@, separated by @sep@.
-- Returns a list of values returned by @p@.
sepBy p sep = sepBy1 p sep +++ return []
--sepBy1 :: ReadP a -> ReadP sep -> ReadP [a]
-- ^ @sepBy1 p sep@ parses one or more occurrences of @p@, separated by @sep@.
-- Returns a list of values returned by @p@.
sepBy1 p sep = liftM2 (:) p (many (sep >> p))
--endBy :: ReadP a -> ReadP sep -> ReadP [a]
-- ^ @endBy p sep@ parses zero or more occurrences of @p@, separated and ended
-- by @sep@.
endBy p sep = many (do x <- p ; sep ; return x)
--endBy1 :: ReadP a -> ReadP sep -> ReadP [a]
-- ^ @endBy p sep@ parses one or more occurrences of @p@, separated and ended
-- by @sep@.
endBy1 p sep = many1 (do x <- p ; sep ; return x)
--chainr :: ReadP a -> ReadP (a -> a -> a) -> a -> ReadP a
-- ^ @chainr p op x@ parses zero or more occurrences of @p@, separated by @op@.
-- Returns a value produced by a /right/ associative application of all
-- functions returned by @op@. If there are no occurrences of @p@, @x@ is
-- returned.
chainr p op x = chainr1 p op +++ return x
--chainl :: ReadP a -> ReadP (a -> a -> a) -> a -> ReadP a
-- ^ @chainl p op x@ parses zero or more occurrences of @p@, separated by @op@.
-- Returns a value produced by a /left/ associative application of all
-- functions returned by @op@. If there are no occurrences of @p@, @x@ is
-- returned.
chainl p op x = chainl1 p op +++ return x
--chainr1 :: ReadP a -> ReadP (a -> a -> a) -> ReadP a
-- ^ Like 'chainr', but parses one or more occurrences of @p@.
chainr1 p op = scan
where scan = p >>= rest
rest x = do f <- op
y <- scan
return (f x y)
+++ return x
--chainl1 :: ReadP a -> ReadP (a -> a -> a) -> ReadP a
-- ^ Like 'chainl', but parses one or more occurrences of @p@.
chainl1 p op = p >>= rest
where rest x = do f <- op
y <- p
rest (f x y)
+++ return x
--manyTill :: ReadP a -> ReadP end -> ReadP [a]
-- ^ @manyTill p end@ parses zero or more occurrences of @p@, until @end@
-- succeeds. Returns a list of values returned by @p@.
manyTill p end = scan
where scan = (end >> return []) <++ (liftM2 (:) p scan)
-- ---------------------------------------------------------------------------
-- Converting between ReadP and Read
--readP_to_S :: ReadP a -> ReadS a
-- ^ Converts a parser into a Haskell ReadS-style function.
-- This is the main way in which you can \"run\" a 'ReadP' parser:
-- the expanded type is
-- @ readP_to_S :: ReadP a -> String -> [(a,String)] @
readP_to_S (R f) = run (f return)
--readS_to_P :: ReadS a -> ReadP a
-- ^ Converts a Haskell ReadS-style function into a parser.
-- Warning: This introduces local backtracking in the resulting
-- parser, and therefore a possible inefficiency.
readS_to_P r =
R (\k -> Look (\s -> final [bs'' | (a,s') <- r s, bs'' <- run (k a) s']))
-- ---------------------------------------------------------------------------
-- QuickCheck properties that hold for the combinators
{- $properties
The following are QuickCheck specifications of what the combinators do.
These can be seen as formal specifications of the behavior of the
combinators.
We use bags to give semantics to the combinators.
> type Bag a = [a]
Equality on bags does not care about the order of elements.
> (=~) :: Ord a => Bag a -> Bag a -> Bool
> xs =~ ys = sort xs == sort ys
A special equality operator to avoid unresolved overloading
when testing the properties.
> (=~.) :: Bag (Int,String) -> Bag (Int,String) -> Bool
> (=~.) = (=~)
Here follow the properties:
> prop_Get_Nil =
> readP_to_S get [] =~ []
>
> prop_Get_Cons c s =
> readP_to_S get (c:s) =~ [(c,s)]
>
> prop_Look s =
> readP_to_S look s =~ [(s,s)]
>
> prop_Fail s =
> readP_to_S pfail s =~. []
>
> prop_Return x s =
> readP_to_S (return x) s =~. [(x,s)]
>
> prop_Bind p k s =
> readP_to_S (p >>= k) s =~.
> [ ys''
> | (x,s') <- readP_to_S p s
> , ys'' <- readP_to_S (k (x::Int)) s'
> ]
>
> prop_Plus p q s =
> readP_to_S (p +++ q) s =~.
> (readP_to_S p s ++ readP_to_S q s)
>
> prop_LeftPlus p q s =
> readP_to_S (p <++ q) s =~.
> (readP_to_S p s +<+ readP_to_S q s)
> where
> [] +<+ ys = ys
> xs +<+ _ = xs
>
> prop_Gather s =
> forAll readPWithoutReadS $ \p ->
> readP_to_S (gather p) s =~
> [ ((pre,x::Int),s')
> | (x,s') <- readP_to_S p s
> , let pre = take (length s - length s') s
> ]
>
> prop_String_Yes this s =
> readP_to_S (string this) (this ++ s) =~
> [(this,s)]
>
> prop_String_Maybe this s =
> readP_to_S (string this) s =~
> [(this, drop (length this) s) | this `isPrefixOf` s]
>
> prop_Munch p s =
> readP_to_S (munch p) s =~
> [(takeWhile p s, dropWhile p s)]
>
> prop_Munch1 p s =
> readP_to_S (munch1 p) s =~
> [(res,s') | let (res,s') = (takeWhile p s, dropWhile p s), not (null res)]
>
> prop_Choice ps s =
> readP_to_S (choice ps) s =~.
> readP_to_S (foldr (+++) pfail ps) s
>
> prop_ReadS r s =
> readP_to_S (readS_to_P r) s =~. r s
-}
......@@ -55,10 +55,9 @@ module Distribution.Package (
#endif
) where
import Control.Monad.State
import Control.Monad(when, foldM)
import Control.Monad.Error
import Data.Char(isSpace, toLower)
import Data.Char
import Data.List(isPrefixOf)
import Data.Maybe(fromMaybe)
......@@ -69,7 +68,7 @@ import Distribution.Setup(CompilerFlavor(..))
import System.IO(openFile, IOMode(..), hGetContents)
import Text.ParserCombinators.Parsec
import Compat.ReadP
#ifdef DEBUG
import HUnit (Test(..), (~:), (~=?), assertEqual, assertBool, Assertion, runTestTT)
......@@ -190,13 +189,14 @@ parsePackageDesc p = do h <- openFile p ReadMode
-> error "no library listed, and no executable stanza."
Right x -> return x
data PError = Parsec ParseError | FromString String
data PError = AmbigousParse | NoParse | FromString String
deriving Show
instance Error PError where
strMsg = FromString
showError (Parsec pe) = show pe
showError AmbigousParse = "Ambigous parse"
showError NoParse = "No parse"
showError (FromString s) = s
parseDescription :: String -> Either PError PackageDescription
......@@ -207,14 +207,14 @@ parseDescription inp = do let (st:sts) = splitStanzas inp
where -- The basic stanza, with library building info
parseBasicStanza pkg (f@"name", val) = return (setPkgName val pkg)
parseBasicStanza pkg (f@"version", val) =
do v <- runP f parseVersion val
do v <- runP parseVersion val
return (setPkgVersion v pkg)
parseBasicStanza pkg (f@"copyright", val) = return pkg{copyright=val}
parseBasicStanza pkg (f@"license", val) =
do l <- runP f parseLicense val
do l <- runP parseLicense val
return pkg{license=l}
parseBasicStanza pkg (f@"license-file", val) =
do path <- runP f parseFilePath val
do path <- runP parseFilePath val
return pkg{license=OtherLicense path}
parseBasicStanza pkg (f@"maintainer", val) = return pkg{maintainer=val}
parseBasicStanza pkg (f@"stability", val) = return pkg{stability=val}
......@@ -225,54 +225,57 @@ parseDescription inp = do let (st:sts) = splitStanzas inp
-- Stanzas for executables
parseExecutableStanza (("executable",exeName):st) =
case lookup "main-is" st of
Just xs -> do path <- runP "main-is" parseFilePath xs
Just xs -> do path <- runP parseFilePath xs
binfo <- foldM parseExeHelp emptyBuildInfo st
return $ Executable exeName path binfo
Nothing -> throwError $ strMsg $
Nothing -> fail $
"No 'Main-Is' field found for " ++ exeName ++ " stanza"
parseExecutableStanza ((f,_):st) = throwError $ strMsg $
parseExecutableStanza ((f,_):st) = fail $
"'Executable' stanza starts with field '" ++ f ++ "'"
parseExeHelp binfo (f@"main-is", _) = return binfo
parseExeHelp binfo (f@"extra-libs", val) =
do xs <- runP f (parseCommaList word) val
do xs <- runP (parseCommaList word) val
return binfo{extraLibs=xs}
parseExeHelp binfo (f@"build-depends", val) =
do xs <- runP f (parseCommaList parseDependency) val
do xs <- runP (parseCommaList parseDependency) val
return binfo{buildDepends=xs}
-- Paths and stuff
parseExeHelp binfo (f@"c-sources", val) =
do paths <- runP f (parseCommaList parseFilePath) val
do paths <- runP (parseCommaList parseFilePath) val
return binfo{cSources=paths}
parseExeHelp binfo (f@"include-dirs", val) =
do paths <- runP f (parseCommaList parseFilePath) val
do paths <- runP (parseCommaList parseFilePath) val
return binfo{includeDirs=paths}
parseExeHelp binfo (f@"includes", val) =
do paths <- runP f (parseCommaList parseFilePath) val
do paths <- runP (parseCommaList parseFilePath) val
return binfo{includes=paths}
parseExeHelp binfo (f@"hs-source-dir", val) =
do path <- runP f parseFilePath val
do path <- runP parseFilePath val
return binfo{hsSourceDir=path}
-- Module related
parseExeHelp binfo (f@"modules", val) =
do xs <- runP f (parseCommaList moduleName) val
do xs <- runP (parseCommaList parseModuleName) val
return binfo{modules=xs}
parseExeHelp binfo (f@"exposed-modules", val) =
do xs <- runP f (parseCommaList moduleName) val
do xs <- runP (parseCommaList parseModuleName) val
return binfo{exposedModules=xs}
parseExeHelp binfo (f@"extensions", val) =
do exts <- runP f (parseCommaList parseExtension) val
do exts <- runP (parseCommaList parseExtension) val
return binfo{extensions=exts}
parseExeHelp binfo (f, val) | "options-" `isPrefixOf` f =
let compilers = [("ghc",GHC),("nhc",NHC),("hugs",Hugs)] -- FIXME
in case lookup (drop 8 f) compilers of
Just c -> do xs <- runP f (parseCommaList parseOption) val
Just c -> do xs <- runP (parseCommaList parseOption) val
return (setOptions c xs binfo)
Nothing -> error $ "Unknown compiler (" ++ drop 8 f ++ ")"
parseExeHelp binfo (field, val) = error $ "Unknown field :: " ++ field
-- ...
runP f p s = case parse p f s of
Left pe -> Left (Parsec pe)
Right a -> Right a
runP :: ReadP a a -> String -> Either PError a
runP p s = case [ x | (x,"") <- readP_to_S p s ] of
[a] -> Right a
[] -> Left NoParse
_ -> Left AmbigousParse
type Stanza = [(String,String)]
......@@ -296,54 +299,40 @@ splitStanzas = map merge . groupStanzas . filter validLine . lines
(fld, "") -> error "FIXME"
-- |parse a module name
moduleName = many (alphaNum <|> oneOf "_'.") <?> "moduleName"
parseFilePath :: GenParser Char st FilePath
parseFilePath = parseReadS <|> (many1 (alphaNum <|> oneOf "-+/_."))
<?> "parseFilePath"
parseReadS :: Read a => GenParser Char st a
parseReadS = do toks <- getInput
case reads toks of
[(str,toks')] -> do setInput toks'
return str
_ -> fail "Bad String"
parseDependency :: GenParser Char st Dependency
parseDependency = do name <- many1 (letter <|> digit <|> oneOf "-_")
skipMany parseWhite
ver <- parseVersionRange <|> return AnyVersion
skipMany parseWhite
parseModuleName :: ReadP r String
parseModuleName = do x <- satisfy isUpper
xs <- munch (\x -> isAlphaNum x || x `elem` "_'.")
return (x:xs)