{- |

Module : ./CommonLogic/Lexer_KIF.hs

Description : Parser of the Knowledge Interchange Format

Copyright : (c) Karl Luc, DFKI Bremen 2010, Soeren Schulze 2012

License : GPLv2 or higher

Maintainer : s.schulze@uni-bremen.de

Stability : experimental

Portability : portable

-}

module CommonLogic.Lexer_KIF where

import Common.Id as Id

import qualified Common.Lexer as Lexer

import Common.Parsec

import Text.ParserCombinators.Parsec as Parsec

import Data.Char (isSpace, isUpper, isLower, isDigit, isAscii)

import Control.Monad (liftM)

-- literally from Lexer_CLIF.hs -- abstract?

skip :: CharParser st String

skip = liftM concat $ many white

pToken :: CharParser st String -> CharParser st Token

pToken p = Lexer.pToken p << skip

oParenT :: CharParser st Token

oParenT = pToken $ string "("

cParenT :: CharParser st Token

cParenT = pToken $ string ")"

parens :: CharParser st a -> CharParser st a

parens p = oParenT >> p << cParenT

key :: String -> CharParser st Id.Token

key s = pToken $ try $ string s << notFollowedBy (satisfy kifWordChar)

word :: CharParser st String

word = satisfy kifInitialChar <:> many (satisfy kifWordChar)

quotedChar :: CharParser st Char

quotedChar =

satisfy kifChar <|> satisfy kifUnofficial

<|> (char '\\' >> char '\"')

quotedString :: CharParser st String

quotedString = do

q1 <- char '\"'

s <- many quotedChar

q2 <- char '\"'

return $ q1 : s ++ [q2]

variable :: CharParser st String

variable = char '?' <:> word

-- Row variables are called Sequences Markers in CommonLogic

rowvar :: CharParser st String

rowvar = char '@' >> liftM ("..." ++) word

sign :: CharParser st String

sign = option "" (string "-")

number :: CharParser st String

number = sign <++> many1 (satisfy kifDigit)

<++> option "" (char '.' <:> many1 (satisfy kifDigit))

<++> option "" (oneOf "eE" <:> sign <++> many1 (satisfy kifDigit))

kifUpper :: Char -> Bool

kifUpper ch = Data.Char.isUpper ch && Data.Char.isAscii ch

kifLower :: Char -> Bool

kifLower ch = Data.Char.isLower ch && Data.Char.isAscii ch

kifSpecial :: Char -> Bool

kifSpecial ch = ch `elem` "!$%&*+-,./<=>?@_~"

-- These characters are used in documentation texts in SUMO.

kifUnofficial :: Char -> Bool

kifUnofficial ch = ch `elem` ",()#':{}`;^"

kifWordChar :: Char -> Bool

kifWordChar ch = kifUpper ch || kifLower ch || kifSpecial ch || kifDigit ch

|| ch == '-' || ch == '#'

-- '#' is used in expanded IRIs

kifChar :: Char -> Bool

kifChar ch = kifUpper ch || kifLower ch || kifSpecial ch || kifDigit ch

|| isSpace ch

kifInitialChar :: Char -> Bool

kifInitialChar ch = kifUpper ch || kifLower ch

kifDigit :: Char -> Bool

kifDigit = isDigit

commentLine :: CharParser st String

commentLine = char ';' <:> many (noneOf "\n")

white :: CharParser st String

white =

many1 (satisfy isSpace)

<|>

commentLine