From: viisi@... (Andi Riedl)
Date: 2001-06-21T08:20:48+09:00
Subject: [ruby-talk:16669] how to call super from singleton method?

hi!

from a singleton method i want to call the
hidden class method. directly using the
ruby executable this works perfectly:

#v+

x = {}

def x.inspect
  p "myInspect"
  super
end

p x.inspect

#v-

output is:

"myInspect"
"{}"

....but when i try to perform this using the C API:

#v+

#include <stdio.h>
#include <ruby.h>

VALUE myInspect (VALUE self)
{
  printf ("myInspect\n");
  return rb_call_super(0,0);
}

int main()
{
  VALUE x,y;
  
  ruby_init();

  x = rb_hash_new();
  rb_define_singleton_method(x,"inspect",(VALUE (*)()) myInspect,0);

  /* call now: */
  y = rb_funcall(x,rb_intern("inspect"),0);
  printf ("%s\n",STR2CSTR(y));
  
  return 0;
}

#v-

it fails:

myInspect
ruby:0:in inspect': superclass method inspect' must be enabled by
rb_enable_super() (NameError)
		  from ruby:0
		  
with 1.6.3 & 1.7.0 (2001-05-24)


so i tried to replace the 'call now' section:

#v+
  /* call now: */
  rb_gv_set("$x",x);
  rb_eval_string("p $x");  
#v-

....which results in the same error.

** but **:

#v+
  /* call now: */
  rb_gv_set("$x",x);
  rb_eval_string("f=$x.method(:inspect); p f.call"); 
#v-

surprisingly works well! 
output is:

myInspect
"{}"

(besides using a global variable is not applicable at all)


so, how can this be done properly?

ciao, andi