From: Daniel Berger <djberg96@...>
Date: 2007-02-14T07:30:16+09:00
Subject: Converting class_for to a C extension

Hi all,

I found this snippet posted to handle doing const_get for nested
classes/modules:

def class_for(class_name)
   names = class_name.split("::")
   result = Object
   names.each { |n|
      result = result.const_get(n)
   }
   result
rescue NameError
   nil
end

I'm trying to convert this to a C extension, but I'm having some
trouble:

static VALUE class_for(VALUE klass_name){
   VALUE v_names, v_result;
   ID id_split = rb_intern("split");
   int i;

   v_names  = rb_funcall(klass_name, id_split, 1, rb_str_new2("::"));
   v_result = rb_cObject;

   for(i = 0; i < RARRAY(v_names)->len; i++)
      v_result = rb_const_get(RBASIC(v_result)->klass, RARRAY(v_names)-
>ptr[i]);

   return v_result;
}

With this code I get "uninitialized constant Class::(null)
(NameError)".

It appears to be a problem with the first argument to rb_const_get().
I'm not sure what that value should be, but I also tried
TYPE(v_result) - which caused a segfault - and just v_result - which
resulted in a similar "uninitialized constant (null) (NameError)"
error.

What am I doing wrong here?

Thanks,

Dan

PS - Yes, I realize I'm not doing error handling in the C extension -
I'm not worried about that for now.