Idea: support uint datatype?

[chtenb]

We support arbitrary sized ints through the int type, and fixed size unsigned ints, like uint32. Would it make sense to also support arbitrary sized uints? The use case I'm thinking of has mostly to do with data modeling and keeping the representation space small for your datatypes. It occurs often naturally that some value should never be negative, and if your function parameter accepts an int you would have to verify that it is indeed positive, which not only is cumbersome to do, but also adds exn to the effect list of the function.