2005-09-03 03:37:58 +00:00

239 lines
7.6 KiB
Haskell

{-# OPTIONS -fglasgow-exts #-}
--
-- Copyright (C) 2004-5 Don Stewart - http://www.cse.unsw.edu.au/~dons
--
-- This program is free software; you can redistribute it and/or
-- modify it under the terms of the GNU General Public License as
-- published by the Free Software Foundation; either version 2 of
-- the License, or (at your option) any later version.
--
-- This program is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
-- General Public License for more details.
--
-- You should have received a copy of the GNU General Public License
-- along with this program; if not, write to the Free Software
-- Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
-- 02111-1307, USA.
--
module System.Plugins.Parser (
parse, mergeModules, pretty, parsePragmas,
HsModule(..) ,
replaceModName
) where
#include "../../config.h"
import Data.List
import Data.Char
import Data.Either
#if defined(WITH_HSX)
import Language.Haskell.Hsx
#else
import Language.Haskell.Parser
import Language.Haskell.Syntax
import Language.Haskell.Pretty
#endif
--
-- | parse a file (as a string) as Haskell src
--
parse :: FilePath -- ^ module name
-> String -- ^ haskell src
-> Either String HsModule -- ^ abstract syntax
parse f fsrc =
#if defined(WITH_HSX)
case parseFileContentsWithMode (ParseMode f) fsrc of
#else
case parseModuleWithMode (ParseMode f) fsrc of
#endif
ParseOk src -> Right src
ParseFailed loc _ -> Left $ srcmsg loc
where
srcmsg loc = "parse error in " ++ f ++ "\n" ++
"line: " ++ (show $ srcLine loc) ++
", col: " ++ (show $ srcColumn loc)++ "\n"
--
-- | pretty print haskell src
--
-- doesn't handle operators with '#' at the end. i.e. unsafeCoerce#
--
pretty :: HsModule -> String
pretty code = prettyPrintWithMode (defaultMode { linePragmas = True }) code
-- | mergeModules : generate a full Haskell src file, give a .hs config
-- file, and a stub to take default syntax and decls from. Mostly we
-- just ensure they don't do anything bad, and that the names are
-- correct for the module.
--
-- Transformations:
--
-- . Take src location pragmas from the conf file (1st file)
-- . Use the template's (2nd argument) module name
-- . Only use export list from template (2nd arg)
-- . Merge top-level decls
-- . need to force the type of the plugin to match the stub,
-- overwriting any type they supply.
--
mergeModules :: HsModule -> -- Configure module
HsModule -> -- Template module
HsModule -- A merge of the two
mergeModules (HsModule l _ _ is ds )
(HsModule _ m' es' is' ds')
= (HsModule l m' es'
(mImps m' is is')
(mDecl ds ds') )
--
-- | replace Module name with String.
--
replaceModName :: HsModule -> String -> HsModule
replaceModName (HsModule l _ es is ds) nm = (HsModule l (Module nm) es is ds)
--
-- | merge import declarations:
--
-- * ensure that the config file doesn't import the stub name
-- * merge import lists uniquely, and when they match, merge their decls
--
-- TODO * we don't merge imports of the same module from both files.
-- We should, and then merge the decls in their import list
-- * rename args, too confusing.
--
-- quick fix: strip all type signatures from the source.
--
mImps :: Module -> -- plugin module name
[HsImportDecl] -> -- conf file imports
[HsImportDecl] -> -- stub file imports
[HsImportDecl]
mImps plug_mod cimps timps =
case filter (!~ self) cimps of cimps' -> unionBy (=~) cimps' timps
where
self = ( HsImportDecl undefined plug_mod undefined undefined undefined )
--
-- | merge top-level declarations
--
-- Remove decls found in template, using those from the config file.
-- Need to sort decls by types, then decls first, in both.
--
-- Could we write a pass to handle editor, foo :: String ?
-- We must keep the type from the template.
--
mDecl ds es = let ds' = filter (not.typeDecl) ds
in sortBy decls $! unionBy (=~) ds' es
where
decls a b = compare (encoding a) (encoding b)
typeDecl :: HsDecl -> Bool
typeDecl (HsTypeSig _ _ _) = True
typeDecl _ = False
encoding :: HsDecl -> Int
encoding d = case d of
HsFunBind _ -> 1
HsPatBind _ _ _ _ -> 1
_ -> 0
--
-- syntactic equality over the useful Haskell abstract syntax
-- this may be extended if we try to merge the files more thoroughly
--
class SynEq a where
(=~) :: a -> a -> Bool
(!~) :: a -> a -> Bool
n !~ m = not (n =~ m)
instance SynEq HsDecl where
(HsPatBind _ (HsPVar n) _ _) =~ (HsPatBind _ (HsPVar m) _ _) = n == m
(HsTypeSig _ (n:_) _) =~ (HsTypeSig _ (m:_) _) = n == m
_ =~ _ = False
instance SynEq HsImportDecl where
(HsImportDecl _ m _ _ _) =~ (HsImportDecl _ n _ _ _) = n == m
--
-- | Parsing option pragmas.
--
-- This is not a type checker. If the user supplies bogus options,
-- they'll get slightly mystical error messages. Also, we /want/ to
-- handle -package options, and other /static/ flags. This is more than
-- GHC.
--
-- GHC user's guide :
--
-- > OPTIONS pragmas are only looked for at the top of your source
-- > files, up to the first (non-literate,non-empty) line not
-- > containing OPTIONS. Multiple OPTIONS pragmas are recognised.
--
-- based on getOptionsFromSource(), in main\/DriverUtil.hs
--
parsePragmas :: String -- ^ input src
-> ([String],[String]) -- ^ normal options, global options
parsePragmas s = look $ lines s
where
look [] = ([],[])
look (l':ls) =
let l = remove_spaces l'
in case () of
() | null l -> look ls
| prefixMatch "#" l -> look ls
| prefixMatch "{-# LINE" l -> look ls
| Just (Option o) <- matchPragma l
-> let (as,bs) = look ls in (words o ++ as,bs)
| Just (Global g) <- matchPragma l
-> let (as,bs) = look ls in (as,words g ++ bs)
| otherwise -> ([],[])
--
-- based on main\/DriverUtil.hs
--
-- extended to handle dynamic options too
--
data Pragma = Option !String | Global !String
matchPragma :: String -> Maybe Pragma
matchPragma s
| Just s1 <- maybePrefixMatch "{-#" s, -- -}
Just s2 <- maybePrefixMatch "OPTIONS" (remove_spaces s1),
Just s3 <- maybePrefixMatch "}-#" (reverse s2)
= Just (Option (reverse s3))
| Just s1 <- maybePrefixMatch "{-#" s, -- -}
Just s2 <- maybePrefixMatch "GLOBALOPTIONS" (remove_spaces s1),
Just s3 <- maybePrefixMatch "}-#" (reverse s2)
= Just (Global (reverse s3))
| otherwise
= Nothing
remove_spaces :: String -> String
remove_spaces = reverse . dropWhile isSpace . reverse . dropWhile isSpace
--
-- verbatim from utils\/Utils.lhs
--
prefixMatch :: Eq a => [a] -> [a] -> Bool
prefixMatch [] _str = True
prefixMatch _pat [] = False
prefixMatch (p:ps) (s:ss) | p == s = prefixMatch ps ss
| otherwise = False
maybePrefixMatch :: String -> String -> Maybe String
maybePrefixMatch [] rest = Just rest
maybePrefixMatch (_:_) [] = Nothing
maybePrefixMatch (p:pat) (r:rest)
| p == r = maybePrefixMatch pat rest
| otherwise = Nothing