[Haskell-cafe] Maybe a, The Rationale

PR Stanley 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 
> functions.
>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?

                 Cheers, Paul 

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