src/Parse/ParserLib.hs · elk

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elk/src/Parse/ParserLib.hs

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1module ParserLib where

3import Ast

4import Combinators

5import Data.Char (isUpper)

6import Tokens

8var_noSpace = do { t <- item; case t of { ID v -> return v; _ -> zero } }

9var = whitespace >> var_noSpace

10cap_var = do

11 whitespace; t <- item

12 case t of { ID (v:vs) -> if isUpper v then return (v:vs) else zero }

14chr = do { whitespace; t <- item; case t of { CHAR c -> return c; _ -> zero } }

16t_noSpace token = sat (==token)

17t_withSpace token = forcedWS >> sat (==token)

18t token = whitespace >> sat (==token)

20forcedWS = do { sat (==SPACES); star nl_space } +|+ plus nl_space

21 where nl_space = plus (sat (==NEWLINE)) >> sat (==SPACES)

22whitespace = optional forcedWS

24accessible exp = do

25 e <- exp

26 access <- optional $ op_parser_nospace (==".")

27 case access of

28 Just "." -> accessible (var >>= return . Access e)

29 Nothing -> return e

31op_parser_nospace pred =

32 do { t <- item

33 ; case t of { OP op -> if pred op then return op else zero; _ -> zero } }

34op_parser pred = whitespace >> op_parser_nospace pred

35anyOp = op_parser (const True)

36assign = op_parser (=="=")