Method: Module#alias_method

Defined in:

vm_method.c

#alias_method(new_name, old_name) ⇒ Object

Makes new_name a new copy of the method old_name. This can be used to retain access to methods that are overridden.

module Mod
  alias_method :orig_exit, :exit #=> :orig_exit
  def exit(code=0)
    puts "Exiting with code #{code}"
    orig_exit(code)
  end
end
include Mod
exit(99)

produces:

Exiting with code 99

# File 'vm_method.c', line 2377

static VALUE
rb_mod_alias_method(VALUE mod, VALUE newname, VALUE oldname)
{
    ID oldid = rb_check_id(&oldname);
    if (!oldid) {
        rb_print_undef_str(mod, oldname);
    }
    VALUE id = rb_to_id(newname);
    rb_alias(mod, id, oldid);
    return ID2SYM(id);
}