From: Charles Mills <cmills@...>
Date: 2005-09-24T05:21:40+09:00
Subject: Re: to_str in string.c # rb_str_to_str()

Timothy Byrd wrote:
> I have a Bignum object and I tried calling StringValueCStr() to get it
> in string form.  This raises:
>
> (eval): cannot convert Bignum into String (TypeError)
>
> I believe this is ultimately because this routine in string.c is being
> called:
>
> VALUE
> rb_str_to_str(str)
>     VALUE str;
> {
>     return rb_convert_type(str, T_STRING, "String", "to_str");
> }
>
> Why is to_str used here?  Should it be to_s, since only a few classes
> seem to have to_str?
>
> -- Timothy

No, it should be to_str.  All objects implement to_s since all classes
are decendents of Object which implements to_s.  to_str is reserved for
objects that behave like a string.  So if you implemented your own
special string class (take your pick
http://www.and.org/vstr/comparison.html) then you should implement
to_str (and to_str should convert an instance of your string class into
a Ruby String object).

Use rb_String(num) or rb_big2str(num, 10).

-Charlie