CODEWITHSUNDEEP
haskell
Marian-Daniel Craciunescu
Marian-Daniel Craciunescu

Reputation: 164

Text.ParserCombinators

I want to make a parser combinator for regular expressions in Haskell. So I defined my own data type and made a match function for this type. I recently discovered about Text.ParserCombinators. If I use parseTest function the result type is IO. So how do I use Text.ParserCombinators to return the type of my created data? Below is my code.

data Reg = Eps
        |Sym Char --caracter
        |Alt Reg Reg --a sau b a|b
        |Seq Reg Reg -- secventa ab  sau chiar paranteza
        |Rep (Int, Maybe Int) Reg   --Star repet on or more time
        |Dif Reg    --not
deriving (Show)
--match function
accept :: Reg -> String ->Bool

accept ( parse term "abcd") "abcd"
ERROR - Type error in application
*** Expression     : accept (parse term "abcd") "abcd"
*** Term           : parse term "abcd"
*** Type           : [Char] -> Either ParseError Reg
*** Does not match : Reg
--term is the Parser function where the grammars is defined
term :: Parser Reg
term = buildExpressionParser ops atom where

Upvotes: 0

Views: 189

Answers (1)

sclv
sclv

Reputation: 38901

As sdcvvc notes in the comments, parse isn't applied to enough arguments.

Upvotes: 1

Related Questions