Thanks, I'd thought it was something to do with incompatible types. I can now create a simpler problem:
tester2 = reserved "parameter" <|> symbol ":"
Certainly I could use reserved ":" instead of symbol, but where is my thinking with symbol here going wrong? Surely the above example isn't so odd?
Paul
-----Original Message-----
From: Luke Palmer [mailto:lrpalmer@gmail.com]
Sent: Fri 3/28/2008 12:26 AM
To: Paul Keir
Cc: haskell-cafe@haskell.org
Subject: Re: [Haskell-cafe] Parsec Expected Type
Hi Paul,
2008/3/27 Paul Keir
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-ParserComb...): 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