Re: [Haskell-cafe] Re: Adding an ignore function to Control.Monad

11 Jul 2009

      On Saturday 11 July 2009 3:35:27 am Jeff Wheeler wrote:
...
On Fri, Jul 10, 2009 at 10:10 PM, Don Stewart wrote:
...
...
## Control.Monad.void m a -> m ()
Don Stewart
Iavor Diatchki
For whatever it's worth, I prefer void as well, for the exact reason
Don said. Indeed, 'ignore' indicates to me that the argument won't
even be evaluated: it'll be ignored, and skipped. But it is, and only
part --- the result --- is ignored.
What about 'void' with functors?
Perhaps it should be noted that 'void' is sometimes associated with the type:

  data Void

the 'empty' type (which isn't empty in Haskell). In typical catamorphism 
style, void would be its eliminator:

  void :: forall a. Void -> a
  void _ = undefined
  -- if you're writing Agda
  -- void ()

This, doesn't see much use in Haskell, though, so perhaps it's irrelevant.

-- Dan

Re: [Haskell-cafe] Re: Adding an ignore function to Control.Monad

Dan Doel