Here's an example: In my paper "First Class Patterns" http://citeseer.ist.psu.edu/tullsen00first.html, by defining the pattern combinators using MonadPlus, you get standard pattern matching with the Maybe instance of MonadPlus and you get backtracking pattern matching with the [] (list) instance of MonadPlus. - Mark On Feb 12, 2005, at 10:08 AM, Benjamin Pierce wrote:
I have seen lots of examples that show how it's useful to make some type constructor into an instance of Monad.
Where can I find examples showing why it's good to take the trouble to show that something is also a MonadPlus? (I know there are many examples of things that *are* MonadPluses; what I want to know is why this is interesting. :-)
Thanks,
- Benjamin
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