Edit: Although it might (?) be better in the lib/array.arc, unless of course it's already integrated into ac.scm...
Edit2: Also, I hope (vec ...) is a function, not a macro or special form, so that existing code that uses vec as a local variable for a collection, or as a function, can still work.
It can't be put in a .arc file, since it is pure scheme code. Further functions dealing with vectors should go in lib/array.arc, however. And yes, vec is a function.
