From: Eric Hodel <drbrain@...7.net>
Date: 2007-10-11T16:17:45+09:00
Subject: Re: what does print call internally?

On Oct 10, 2007, at 19:58 , 7stud -- wrote:
> Eric Hodel wrote:
>> On Oct 10, 2007, at 15:31 , Martin DeMello wrote:
>>
>>> => foo
>> it calls #to_s.
>
> class Dog
>   def to_s
>     print "dog"
>   end
> end
>
> d = Dog.new
>
> print d
> puts
>
> puts d
>
> --output:--
> dog#<Dog:0x25634>
> dog#<Dog:0x25634>

In IO#write, if #to_s returns nil, rb_any_to_s() gets called, which  
returns "#<#{self.class}:0x#{object_id.to_s 16}>", which gets printed  
instead of your broken #to_s.

--
Poor workers blame their tools. Good workers build better tools. The
best workers get their tools to do the work for them. -- Syndicate Wars