[dllthomas]

Hoogle lets you do exactly that, with fuzzy matching:

https://www.haskell.org/hoogle/?hoogle=a+-%3E+[b]

It's as useful as you might hope!

[anthk]

I am not a Haskeller, but you can use "!h searchterm" on Duck Duck Go.

[ddellacosta]

OMG thank you, this was the thing that got me to finally permanently set my toolbar search in FF to Duck Duck Go...