Named function types
====================

For example:

    type Sorter[ref T] = func(ref T a, ref T B) -> enum SortResult
    func sort(func Sorter sortfunc)

If function references are *required* to be named, then we could
create a jump table for each function type (at load time) and
use integers/indices to store function references.

Similarly, enums could also be required to be named.