Re: [Haskell-cafe] The (!) operation

On Thu, Mar 8, 2012 at 11:19 AM, Christopher Done wrote:

‘Ello.

Is there a generalization of this operator? It's all over the place, it's basically

   (!) :: (Monad m, Indexed collection index value) => index -> container -> m value

We have `(!!)` on lists, `(!)` on maps, vectors, json objects, … (doesn't seem there's one for bytestring)

(Though I seem to recall the monadic return value being frowned upon but I don't recall why.)

Thoughts?

Perhaps Data.Key meets your needs? http://hackage.haskell.org/packages/archive/keys/2.1.2/doc/html/Data-Key.htm... Anthony