+
−{-# LANGUAGE FlexibleContexts, NoMonomorphismRestriction #-}
+
−module PascalBasics where
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−
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−import Text.Parsec.Combinator
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−import Text.Parsec.Char
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−import Text.Parsec.Prim
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−import Text.Parsec.Token
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−import Text.Parsec.Language
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−import Data.Char
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−import Control.Monad
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−import Data.Functor.Identity
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−
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−char' :: Char -> Parsec String u ()
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−char' = void . char
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−
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−string' :: String -> Parsec String u ()
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−string' = void . string
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−
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−builtin :: [String]
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−builtin = ["succ", "pred", "low", "high", "ord", "inc", "dec", "exit", "break", "continue", "length", "copy"]
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−
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−pascalLanguageDef :: GenLanguageDef String u Identity
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−pascalLanguageDef
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−    = emptyDef
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−    { commentStart   = "(*"
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−    , commentEnd     = "*)"
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−    , commentLine    = "//"
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−    , nestedComments = False
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−    , identStart     = letter <|> oneOf "_"
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−    , identLetter    = alphaNum <|> oneOf "_"
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−    , opLetter       = letter
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−    , reservedNames  = [
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−            "begin", "end", "program", "unit", "interface"
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−            , "implementation", "and", "or", "xor", "shl"
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−            , "shr", "while", "do", "repeat", "until", "case", "of"
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−            , "type", "var", "const", "out", "array", "packed"
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−            , "procedure", "function", "with", "for", "to"
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−            , "downto", "div", "mod", "record", "set", "nil"
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−            , "cdecl", "external", "if", "then", "else"
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−            ] -- ++ builtin
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−    , caseSensitive  = False
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−    }
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−
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−preprocessorSwitch :: Stream String Identity Char => Parsec String u String
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−preprocessorSwitch = do
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−    try $ string' "{$"
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−    s <- manyTill (noneOf "\n") $ char '}'
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−    return s
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−
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−caseInsensitiveString :: Stream String Identity Char => String -> Parsec String u String
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−caseInsensitiveString s = do
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−    mapM_ (\a -> satisfy (\b -> toUpper a == toUpper b)) s <?> s
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−    return s
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−
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−pas :: GenTokenParser String u Identity
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−pas = patch $ makeTokenParser pascalLanguageDef
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−    where
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−    patch tp = tp {stringLiteral = stringL}
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−
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−comment :: Stream String Identity Char => Parsec String u String
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−comment = choice [
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−        char '{' >> notFollowedBy (char '$') >> manyTill anyChar (try $ char '}')
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−        , (try $ string "(*") >> manyTill anyChar (try $ string "*)")
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−        , (try $ string "//") >> manyTill anyChar (try newline)
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−        ]
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−
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−comments :: Parsec String u ()
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−comments = do
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−    spaces
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−    skipMany $ do
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−        void $ preprocessorSwitch <|> comment
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−        spaces
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−
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−stringL :: Parsec String u String
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−stringL = do
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−    char' '\''
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−    s <- (many $ noneOf "'")
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−    char' '\''
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−    ss <- many $ do
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−        char' '\''
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−        s' <- (many $ noneOf "'")
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−        char' '\''
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−        return $ '\'' : s'
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−    comments
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−    return $ concat (s:ss)