From: Jens Nissen <frodo.hobbit@...>
Date: 2001-12-20T00:11:42+09:00
Subject: [ruby-talk:28940] Question on String Handling in Ruby 1.6.6.

I'm using ruby 1.6.6 (2001-12-13) [i586-mswin32]. (1.6.5 does not have the
problem!)
Watch the following script in an environment, which has a trace_func set.

#begin demo
a = "Hello"
puts "Bug!" if a != nil
#end demo

What I see, is that an exception is raised, but handled internally. That's
very
annoying for Users using a debugger. Looking at the source code, I'd like to
raise some questions
(in addition to the exception :-))

(1) object.c::rb_check_convert_type
- What is arg2 good for?
- What is the first checking of val good for - the function is only called,
  if TYPE(val) != type (see rb_str_equal)

The code looks somewhat incomplete so I'm rather suspicious of this code.
(It wasn't part of 1.6.5)

(2) Is the following code a bug in string.c::rb_str_equal?

//quote ...
if (TYPE(str2) != T_STRING) {
 str2 = rb_check_convert_type(str2, T_STRING, "String", "to_str");
 if (NIL_P(str2)) return Qfalse;
}
//end quote

This code tries to call the method to_str on objects which are not strings.
But to_str is defined only for Strings (and Exceptions).

Would it be correct to call "to_s" instead, which is defined for most
Objects and
thus makes more sense?

Jens