From: dblack@...
Date: 2007-08-15T09:57:33+09:00
Subject: Re: to_str behavior

Hi --

On Wed, 15 Aug 2007, Steven Lumos wrote:

> dblack@rubypal.com writes:
>> static VALUE
>> rb_str_equal(str1, str2)
>>     VALUE str1, str2;
>> {
>>     if (str1 == str2) return Qtrue;
>>     if (TYPE(str2) != T_STRING) {
>>         if (!rb_respond_to(str2, rb_intern("to_str"))) {
>>             return Qfalse;
>>         }
>>         return rb_equal(str2, str1);
>>     }
>>
>>     if (RSTRING(str1)->len == RSTRING(str2)->len &&
>>         rb_str_cmp(str1, str2) == 0) {
>>         return Qtrue;
>>     }
>>     return Qfalse;
>> }
>>
>> I haven't quite figured out what the point is of testing to see
>> whether str2 responds to "to_str", since even if it does, to_str isn't
>> called. But I might just have to keep following the trail....
>
> Note the order of arguments.  It means str2#== will be used instead of
> String#==.

Interesting. I'm not sure what the point of the to_str test is,
though, since to_str doesn't actually seem to get called.


David

-- 
* Books:
   RAILS ROUTING (new! http://www.awprofessional.com/title/0321509242)
   RUBY FOR RAILS (http://www.manning.com/black)
* Ruby/Rails training
     & consulting:  Ruby Power and Light, LLC (http://www.rubypal.com)