203 lines
No EOL
6 KiB
Haskell
203 lines
No EOL
6 KiB
Haskell
module Parse.Helpers where
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import Control.Applicative ((<$>),(<*>))
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import Control.Monad
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import Control.Monad.State
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import Data.Char (isUpper)
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import SourceSyntax.Helpers as Help
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import SourceSyntax.Location as Location
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import SourceSyntax.Expression
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import Text.Parsec hiding (newline,spaces,State)
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import Text.Parsec.Indent
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reserveds = [ "if", "then", "else"
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, "case", "of"
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, "let", "in"
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, "data", "type"
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, "module", "where"
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, "import", "as", "hiding", "open"
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, "export", "foreign" ]
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expecting = flip (<?>)
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type IParser a = ParsecT String () (State SourcePos) a
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iParse :: IParser a -> SourceName -> String -> Either ParseError a
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iParse aParser source_name input =
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runIndent source_name $ runParserT aParser () source_name input
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backslashed :: IParser Char
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backslashed = do { char '\\'; c <- anyChar
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; return . read $ ['\'','\\',c,'\''] }
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var :: IParser String
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var = makeVar (letter <|> char '_' <?> "variable")
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lowVar :: IParser String
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lowVar = makeVar (lower <?> "lower case variable")
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capVar :: IParser String
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capVar = makeVar (upper <?> "upper case variable")
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qualifiedVar :: IParser String
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qualifiedVar = do
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vars <- many ((++) <$> capVar <*> string ".")
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(++) (concat vars) <$> lowVar
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rLabel :: IParser String
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rLabel = lowVar
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innerVarChar :: IParser Char
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innerVarChar = alphaNum <|> char '_' <|> char '\'' <?> ""
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makeVar :: IParser Char -> IParser String
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makeVar p = do v <- (:) <$> p <*> many innerVarChar
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guard (v `notElem` reserveds)
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return v
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reserved :: String -> IParser String
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reserved word =
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try (string word >> notFollowedBy innerVarChar) >> return word
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<?> "reserved word '" ++ word ++ "'"
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anyOp :: IParser String
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anyOp = betwixt '`' '`' qualifiedVar <|> symOp <?> "infix operator (e.g. +, *, ||)"
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symOp :: IParser String
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symOp = do op <- many1 (satisfy Help.isSymbol)
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guard (op `notElem` [ "=", "..", "->", "--", "|", "\8594", ":" ])
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case op of
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"." -> notFollowedBy lower >> return op
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"\8728" -> return "."
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_ -> return op
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arrow :: IParser String
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arrow = string "->" <|> string "\8594" <?> "arrow (->)"
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hasType :: IParser String
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hasType = string ":" <?> "':' (a type annotation)'"
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commitIf check p = commit <|> try p
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where commit = do (try $ lookAhead check) >> p
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spaceySepBy1 :: IParser b -> IParser a -> IParser [a]
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spaceySepBy1 sep p = do
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a <- p
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(a:) <$> many (commitIf (whitespace >> sep) (whitespace >> sep >> whitespace >> p))
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commaSep1 :: IParser a -> IParser [a]
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commaSep1 = spaceySepBy1 (char ',' <?> "comma ','")
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commaSep :: IParser a -> IParser [a]
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commaSep = option [] . commaSep1
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semiSep1 :: IParser a -> IParser [a]
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semiSep1 = spaceySepBy1 (char ';' <?> "semicolon ';'")
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pipeSep1 :: IParser a -> IParser [a]
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pipeSep1 = spaceySepBy1 (char '|' <?> "type divider '|'")
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consSep1 :: IParser a -> IParser [a]
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consSep1 = spaceySepBy1 (string "::" <?> "cons operator '::'")
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dotSep1 :: IParser a -> IParser [a]
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dotSep1 p = (:) <$> p <*> many (try (char '.') >> p)
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spaceSep1 :: IParser a -> IParser [a]
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spaceSep1 p = (:) <$> p <*> spacePrefix p
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spacePrefix p = constrainedSpacePrefix p (\_ -> return ())
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constrainedSpacePrefix p constraint =
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many . try $ do
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n <- whitespace
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constraint n
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indented
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p
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followedBy a b = do x <- a ; b ; return x
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betwixt a b c = do char a ; out <- c
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char b <?> "closing '" ++ [b] ++ "'" ; return out
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surround a z name p = do
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char a ; whitespace ; v <- p ; whitespace
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char z <?> unwords ["closing", name, show z]
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return v
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braces :: IParser a -> IParser a
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braces = surround '[' ']' "brace"
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parens :: IParser a -> IParser a
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parens = surround '(' ')' "paren"
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brackets :: IParser a -> IParser a
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brackets = surround '{' '}' "bracket"
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addLocation :: IParser (Expr t v) -> IParser (LExpr t v)
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addLocation expr = do
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start <- getPosition
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e <- expr
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end <- getPosition
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return (Location.at start end e)
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accessible :: IParser (LExpr t v) -> IParser (LExpr t v)
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accessible expr = do
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start <- getPosition
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ce@(L _ e) <- expr
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let rest f = do
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let dot = char '.' >> notFollowedBy (char '.')
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access <- optionMaybe (try dot <?> "field access (e.g. List.map)")
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case access of
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Nothing -> return ce
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Just _ -> accessible $ do
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v <- var <?> "field access (e.g. List.map)"
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end <- getPosition
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return (Location.at start end (f v))
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case e of Var (c:cs) | isUpper c -> rest (\v -> Var (c:cs ++ '.':v))
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| otherwise -> rest (Access ce)
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_ -> rest (Access ce)
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spaces :: IParser String
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spaces = concat <$> many1 (multiComment <|> string " ") <?> "spaces"
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forcedWS :: IParser String
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forcedWS = choice [ try $ (++) <$> spaces <*> (concat <$> many nl_space)
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, try $ concat <$> many1 nl_space ]
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where nl_space = try ((++) <$> (concat <$> many1 newline) <*> spaces)
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-- Just eats whitespace until the next meaningful character.
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dumbWhitespace :: IParser String
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dumbWhitespace = concat <$> many (spaces <|> newline)
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whitespace :: IParser String
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whitespace = option "" forcedWS <?> "whitespace"
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freshLine :: IParser [[String]]
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freshLine = try (many1 newline >> many space_nl) <|> try (many1 space_nl) <?> ""
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where space_nl = try $ spaces >> many1 newline
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newline :: IParser String
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newline = simpleNewline <|> lineComment <?> "newline"
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simpleNewline :: IParser String
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simpleNewline = try (string "\r\n") <|> string "\n"
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lineComment :: IParser String
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lineComment = do
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try (string "--")
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comment <- manyTill anyChar $ simpleNewline <|> (eof >> return "\n")
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return ("--" ++ comment)
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multiComment :: IParser String
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multiComment = do { try (string "{-"); closeComment }
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closeComment :: IParser String
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closeComment = do
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comment <- manyTill anyChar . choice $
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[ try (string "-}") <?> "close comment"
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, do { try $ string "{-"; closeComment; closeComment }
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]
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return ("{-" ++ comment ++ "-}") |