elm/compiler/Parse/Parse.hs

73 lines
2.8 KiB
Haskell

{-# OPTIONS_GHC -W #-}
module Parse.Parse (program, dependencies) where
import Control.Applicative ((<$>), (<*>))
import qualified Data.List as List
import qualified Data.Map as Map
import Text.Parsec hiding (newline,spaces)
import qualified Text.PrettyPrint as P
import qualified SourceSyntax.Declaration as D
import qualified SourceSyntax.Module as M
import Parse.Helpers
import Parse.Declaration (infixDecl)
import Parse.Module
import qualified Parse.Declaration as Decl
import Transform.Declaration (combineAnnotations)
freshDef = commitIf (freshLine >> (letter <|> char '_')) $ do
freshLine
Decl.declaration <?> "another datatype or variable definition"
decls = do d <- Decl.declaration <?> "at least one datatype or variable definition"
(d:) <$> many freshDef
program :: OpTable -> String -> Either [P.Doc] (M.Module D.Declaration)
program table src =
do (M.Module names exs ims parseDecls) <- setupParserWithTable table programParser src
decls <- either (\err -> Left [P.text err]) Right (combineAnnotations parseDecls)
return $ M.Module names exs ims decls
programParser :: IParser (M.Module D.ParseDeclaration)
programParser =
do optional freshLine
(names,exports) <- option (["Main"],[]) (moduleDef `followedBy` freshLine)
is <- (do try (lookAhead $ reserved "import")
imports `followedBy` freshLine) <|> return []
declarations <- decls
optional freshLine ; optional spaces ; eof
return $ M.Module names exports is declarations
dependencies :: String -> Either [P.Doc] (String, [String])
dependencies =
let getName = List.intercalate "." . fst in
setupParser $ do
optional freshLine
(,) <$> option "Main" (getName <$> moduleDef `followedBy` freshLine)
<*> option [] (map fst <$> imports `followedBy` freshLine)
setupParserWithTable :: OpTable -> IParser a -> String -> Either [P.Doc] a
setupParserWithTable table p source =
do localTable <- setupParser parseFixities source
case Map.intersection table localTable of
overlap | not (Map.null overlap) -> Left [ msg overlap ]
| otherwise ->
flip setupParser source $ do
putState (Map.union table localTable)
p
where
msg overlap =
P.vcat [ P.text "Parse error:"
, P.text $ "Overlapping definitions for infix operators: " ++
List.intercalate " " (Map.keys overlap)
]
parseFixities = do
decls <- onFreshLines (:) [] infixDecl
return $ Map.fromList [ (op,(lvl,assoc)) | D.Fixity assoc lvl op <- decls ]
setupParser :: IParser a -> String -> Either [P.Doc] a
setupParser p source =
case iParse p source of
Right result -> Right result
Left err -> Left [ P.text $ "Parse error at " ++ show err ]