1 {-# LANGUAGE FlexibleContexts #-}

     2 module PascalBasics where

     3 

     4 import Text.Parsec.Combinator

     5 import Text.Parsec.Char

     6 import Text.Parsec.Prim

     7 import Text.Parsec.Token

     8 import Text.Parsec.Language

     9 import Data.Char

    10 

    11 builtin = ["succ", "pred", "low", "high", "ord", "inc", "dec", "exit", "break", "continue", "length"]

    12 

    13 pascalLanguageDef

    14     = emptyDef

    15     { commentStart   = "(*"

    16     , commentEnd     = "*)"

    17     , commentLine    = "//"

    18     , nestedComments = False

    19     , identStart     = letter <|> oneOf "_"

    20     , identLetter    = alphaNum <|> oneOf "_"

    21     , reservedNames  = [

    22             "begin", "end", "program", "unit", "interface"

    23             , "implementation", "and", "or", "xor", "shl"

    24             , "shr", "while", "do", "repeat", "until", "case", "of"

    25             , "type", "var", "const", "out", "array", "packed"

    26             , "procedure", "function", "with", "for", "to"

    27             , "downto", "div", "mod", "record", "set", "nil"

    28             , "cdecl", "external", "if", "then", "else"

    29             ] -- ++ builtin

    30     , reservedOpNames= []

    31     , caseSensitive  = False

    32     }

    33 

    34 preprocessorSwitch :: Stream s m Char => ParsecT s u m String

    35 preprocessorSwitch = do

    36     try $ string "{$"

    37     s <- manyTill (noneOf "\n") $ char '}'

    38     return s

    39 

    40 caseInsensitiveString s = do

    41     mapM_ (\a -> satisfy (\b -> toUpper a == toUpper b)) s <?> s

    42     return s

    43 

    44 pas = patch $ makeTokenParser pascalLanguageDef

    45     where

    46     patch tp = tp {stringLiteral = stringL}

    47 

    48 comment = choice [

    49         char '{' >> notFollowedBy (char '$') >> manyTill anyChar (try $ char '}')

    50         , (try $ string "(*") >> manyTill anyChar (try $ string "*)")

    51         , (try $ string "//") >> manyTill anyChar (try newline)

    52         ]

    53 

    54 comments = do

    55     spaces

    56     skipMany $ do

    57         preprocessorSwitch <|> comment

    58         spaces

    59 

    60 stringL = do

    61     (char '\'')

    62     s <- (many $ noneOf "'")

    63     (char '\'')

    64     ss <- many $ do

    65         (char '\'')

    66         s' <- (many $ noneOf "'")

    67         (char '\'')

    68         return $ '\'' : s'

    69     comments

    70     return $ concat (s:ss)