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

Subject: Re: [Haskell-cafe] Maybe, maybe not.
From: Daniel Peebles
Date: Tue, 26 Jan 2010 23:25:28 -0500
There are actually only two (extensionally) possible total functions with that type, as far as I can see :)

On Tue, Jan 26, 2010 at 11:12 PM, michael rice <[email protected]> wrote:
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 <[email protected]> wrote:

From: Edward Z. Yang <[email protected]>
Subject: Re: [Haskell-cafe] Maybe, maybe not.
To: "michael rice" <[email protected]>
Cc: "haskell-cafe" <[email protected]>
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


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