Returns a Proc object that takes arguments and yields them.
This method is implemented so that a Yielder object can be directly passed to another method as a block argument.
enum = Enumerator.new { |y| Dir.glob("*.rb") { |file| File.open(file) { |f| f.each_line(&y) } } }
static VALUE yielder_to_proc(VALUE obj) { VALUE method = rb_obj_method(obj, sym_yield); return rb_funcall(method, idTo_proc, 0); }