Method: BasicObject#method_missing

Defined in:

vm_eval.c

#method_missing(symbol[, *args]) ⇒ Object (private)

Invoked by Ruby when obj is sent a message it cannot handle. symbol is the symbol for the method called, and args are any arguments that were passed to it. By default, the interpreter raises an error when this method is called. However, it is possible to override the method to provide more dynamic behavior. If it is decided that a particular method should not be handled, then super should be called, so that ancestors can pick up the missing method. The example below creates a class Roman, which responds to methods with names consisting of roman numerals, returning the corresponding integer values.

class Roman
  def roman_to_int(str)
    # ...
  end

  def method_missing(symbol, *args)
    str = symbol.id2name
    begin
      roman_to_int(str)
    rescue
      super(symbol, *args)
    end
  end
end

r = Roman.new
r.iv      #=> 4
r.xxiii   #=> 23
r.mm      #=> 2000
r.foo     #=> NoMethodError

# File 'vm_eval.c', line 877

static VALUE
rb_method_missing(int argc, const VALUE *argv, VALUE obj)
{
    rb_execution_context_t *ec = GET_EC();
    raise_method_missing(ec, argc, argv, obj, ec->method_missing_reason);
    UNREACHABLE_RETURN(Qnil);
}