[Haskell-cafe] Parsec Expected Type
Luke Palmer
lrpalmer at gmail.com
Thu Mar 27 20:26:26 EDT 2008
Hi Paul,
2008/3/27 Paul Keir <pkeir at dcs.gla.ac.uk>:
> Hi,
>
> Does anyone know why this reduced Parsec production stops compilation, and
> how I can fix it?
>
> tester = reserved "parameter"
> <|> do { reserved "dimension"; symbol ":" }
Look at the types of "reserved" and "symbol" (from
http://www.haskell.org/ghc/docs/latest/html/libraries/parsec/Text-ParserCombinators-Parsec-Token.html):
symbol :: String -> CharParser st String
reserved :: String -> CharParser st ()
The type of a do block is the same as the type of its last statement.
But (reserved "parameter") and (symbol ";") do not have the same type.
Luke
More information about the Haskell-Cafe
mailing list