[Haskell-cafe] Maybe a, The Rationale
prstanley at ntlworld.com
Sat May 10 18:56:48 EDT 2008
>> Paul: 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. :-)
> Bob: Pure and simple -- it allows you to represent partial
>Looking up a map will only sometimes find a value, so we either return
>Nothing, or Just that value.
Paul: Would yu like to demonstrate this in an example?
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