15 Jul
2007
15 Jul
'07
6:16 p.m.
Ian Lynagh wrote:
It's in Control.Monad.Instances:
Prelude> :m + Control.Monad.Instances Prelude Control.Monad.Instances> fmap not (Right True) Right False
I don't know if there's a way of deducing that from the haddock documentation.
There doesn't seem to be. I didn't discover that module until I finally
sat down and spent 15 minutes trying to answer the question "why is
importing, or omitting, some completely unrelated mtl module influencing
my program's ability to compile?"
Wonderful as haddock is, there's no substitute for having the GHC
sources and half of hackage unpacked on your hard disk, to make possible
a few rounds of "grep -r".