[Haskell-cafe] Maybe a, The Rationale
tom.davie at gmail.com
Sat May 10 18:49:04 EDT 2008
On 11 May 2008, at 00:36, PR Stanley wrote:
> Hi folks
> data Maybe a = Nothing | Just a
> What is the underlying rationale for the Maybe data type? is it the
> safe style of programming it encourages/
> Something tells me this is going to start a lengthy discussion. :-)
Pure and simple -- it allows you to represent partial functions.
Looking up a map will only sometimes find a value, so we either return
Nothing, or Just that value.
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