25 Jan
2010
25 Jan
'10
7:12 p.m.
On Mon, Jan 25, 2010 at 5:38 PM, Joe Van Dyk
This messes me up:
$ ghci GHCi, version 6.8.2: http://www.haskell.org/ghc/ :? for help double x =Loading package base ... linking ... done. Prelude> double x = x + x <interactive>:1:9: parse error on input `='
Why does that happen?
As others pointed out, you have to use "let" here; I don't know how much you've experimented with monads yet (e.g., IO), but the reason is that you're actually working in a monad in GHCi.