Parsing Indentation-based syntaxes in Haskell's Parsec
- by pavpanchekha
I'm trying to parse an indentation-based language (think Python, Haskell itself, Boo, YAML) in Haskell using Parsec. I've seen the IndentParser library, and it looks like it's the perfect match, but what I can't figure out is how to make my TokenParser into an indentation parser. Here's the code I have so far:
import qualified Text.ParserCombinators.Parsec.Token as T
import qualified Text.ParserCombinators.Parsec.IndentParser.Token as IT
lexer = T.makeTokenParser mylangDef
ident = IT.identifier lexer
This throws the error:
parser2.hs:29:28:
Couldn't match expected type `IT.TokenParser st'
against inferred type `T.GenTokenParser s u m'
In the first argument of `IT.identifier', namely `lexer'
In the expression: IT.identifier lexer
In the definition of `ident': ident = IT.identifier lexer
What am I doing wrong? How should I create an IT.TokenParser? Or is IndentParser broken and to be avoided?
