Re: [Haskell-cafe] Maybe, maybe not.

27 Jan 2010

      Didn't recognize the sameness. Aside from there being many ways to do the same thing, partial application makes the mixup even merrier.

Thanks,

Michael

--- On Tue, 1/26/10, Edward Z. Yang <ezyang@MIT.EDU> wrote:

From: Edward Z. Yang <ezyang@MIT.EDU>
Subject: Re: [Haskell-cafe] Maybe, maybe not.
To: "michael rice" <nowgate@yahoo.com>
Cc: "haskell-cafe" <haskell-cafe@haskell.org>
Date: Tuesday, January 26, 2010, 10:52 PM

Excerpts from michael rice's message of Tue Jan 26 21:34:42 -0500 2010:
...
fromMaybe d x = case x of {Nothing -> d;Just v  -> v}
fromMaybe z = maybe z id
They're equivalent.  Here the definition of maybe:

    maybe :: b -> (a -> b) -> Maybe a -> b
    maybe n _ Nothing  = n
    maybe _ f (Just x) = f x

Cheers,
Edward