JuliaLang/julia — comment on commit d3f4f18fed1e0c867c28f914125da03adbfdb21b
File: j/string.j line 698
By JeffBezanson:

well we just want to allow any collection that might contain characters. we don't really need to dispatch on whether this argument is a Set, so there's no reason to introduce a dependency on the Set type.