Question

When I need look for what package contains a symbol I use Google or Hoogle. 99% cases I found a reference to Hackage (it’s good).

There’s way to lookup locally?

Example:

$ ghci
Prelude> :i MonadState
Not in scope: data constructor `MonadState'

then I search “hackage MonadState” and found

http://hackage.haskell.org/.../Control-Monad-State-Class.html

Then:

Prelude> :m Control.Monad.State
Prelude> etc...

How you do?

Thank you very much!

Answer 1

To search locally installed packages for symbols, use hoogle:

$ cabal install hoogle
...

# generate a database of symbols
$ hoogle data
...

$ hoogle search MonadState
Control.Monad.State.Class class Monad m => MonadState s m | m -> s
Control.Monad.State.Lazy class Monad m => MonadState s m | m -> s
Control.Monad.State.Strict class Monad m => MonadState s m | m -> s