10 May
2008
10 May
'08
10:56 p.m.
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