Hello.
The Parsec library (in package text from hslibs)
distributed with GHC 4.08.1 and from CVS does not
work as expected. When I try the attached
program, ghc gives me error messages:
=================================
test.hs:6:
Couldn't match `TokenParser' against `[Char]'
Expected type: TokenParser
Inferred type: [Char]
In the first argument of `symbol', namely `"let"'
In a do statement: symbol "let"
test.hs:12:
Ambiguous type variable(s) `a' in the constraint `Show a'
arising from use of `print' at test.hs:12
In the right-hand side of an equation for `main':
print (parse pLet "" "let a = 232")
Compilation had errors
=================================
This same program works if I use the Parsec library
downloaded from the author page <http://www.cs.uu.nl/~daan>
(after correcting a small bug relative to using some
names from the Char module without importing them).
I hope the library gets updated in the GHC CVS repository
and the next GHC release corrects this problem.
Regards,
Romildo
--
Prof. José Romildo Malaquias <[EMAIL PROTECTED]>
Departamento de Computação
Universidade Federal de Ouro Preto
Brasil
module Main where
import Parsec
import ParsecToken
pLet = do symbol "let"
id <- identifier
symbol "="
x <- integer
return (id,x)
main = print (parse pLet "" "let a = 232")
