Cagdas Ozgenc
Greetings,
Is identity function the only meaningful function one can write without constraining the type variable using a typeclass? If not, could you please give a counter-example?
Certainly you can write lots of ``meaningful function''s without type classes: not, (&&), (||), as well as many more complicated functions at more complicated types. You can also write useful polymorphic functions without type classes, as long as you specify at least one type. For example, you can write polymorphic functions over/yielding lists, such as repeat, cycle, map and its many relatives, foldr and its many relatives, take and its relatives, takeWhile and its relatives, etc. Similar functions often exist for other types. I'm somewhat curious, though: why do you ask this question? How do you expand your question that makes the answer seem to be ``no''?
Thanks
Jon Cast