From: dblack@...
Date: 2006-07-30T01:58:29+09:00
Subject: Re: to_i vs. to_int

Hi --

On Sun, 30 Jul 2006, gabriele renzi wrote:

> Ico ha scritto:
>> Hello,
>> 
>> I have a class which instances can be represented as integers. What is
>> the difference between the to_i and to_int methods, and when is which
>> form needed ?
>
> short names (to_x) are for common programmer use.
> Long names (to_xyz) are there so that ruby can do some implicit conversions 
> between things that can basically be threated as xyz.
>
> So in your case it could be meaningful to define one and alias the other to 
> it.

What's a use case for to_int?  I was thinking of this classic to_str
example:

   class S
     def to_str
       "some text"
     end
   end

   puts "Here is " + S.new   # Here is some text

But the to_int equivalent doesn't work:

   class S
     def to_int
       2
     end
   end

   puts 2 + S.new    # TypeError: S can't be coerced into Fixnum

Same thing with:

   puts Integer(2) + S.new

I'm stuck trying to find a case where to_int does what to_str does --
but maybe it doesn't.


David

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