From: Phrogz <phrogz@...>
Date: 2007-10-11T12:35:03+09:00
Subject: Re: what does print call internally?

On Oct 10, 9:25 pm, 7stud -- <dol...@excite.com> wrote:
> I don't understand the output of my first example: print returns nil, so
> print 'dog' should return nil, which means to_s returns nil, and so
> print d should be equivalent to print nil.

If to_s returns something other than a string, Ruby shakes a naughty
finger at you and ignores you, and falls back on the result of
Kernel#inspect instead.

irb(main):001:0> class Foo; def to_s; 42; end; end
=> nil
irb(main):002:0> puts Foo.new
#<Foo:0x359224>
=> nil
irb(main):003:0> class Foo; def to_s; "42"; end; end
=> nil
irb(main):004:0> puts Foo.new
42