On May 24, 2011, at 4:46 AM, Ketil Malde wrote:
Replying with a pointer to 'catMaybes' resulted in (most likely) the author going off to finish/improve his program, and some more interesting discussion on alternative ways to do this.
What's more, the thread added many other possible implementations, and a discussion why using filter ((/=) Nothing) is a bad thing (even though it seems like a nice and simple check) because it adds an additional Eq constraint an whatever is inside the Maybe. I think THAT, ie, not only accepting and giving useful answers to simple questions, but even expanding upon them and using them as learning tools for more advanced topics, is what makes the haskell community such a fun place to be. Because while I, a medium level haskell noobie, already knew about the catMaybes function and could have built the filters or searched on Hoogle for it, I had not thought about the advantages to using isNothing instead of (== Nothing), or that there was any difference at all.