From: Martin Weber <Ephaeton@...>
Date: 2003-03-30T09:11:09+09:00
Subject: Re: [Ruby] Java-like toString() method?

On Sun, Mar 30, 2003 at 07:47:57AM +0900, Stephan K�mper wrote:
> Frank Thomas wrote:
> >In Java one can define a toString() method which will return a certain
> >string when printing an instance of the object containing the toString()
> >method.
> >
> >Is there anything like that in Ruby?
> >
> 
> Hi Frank,
> 
> I think to_s is what's called when you print an object.

Actually I think it's inspect, not to_s - that is depending
on what the question was *exactly*

> 1
1

> class Fixnum
> def inspect
>	"Ruby is %d times more fun than Java!" % self
> end
> def to_s
>	"Java is %d times more fun than Ruby!" % self
> end
> def lies
>	"#{self}"
> end
> end
nil

> 1000
Ruby is 1000 times more fun than Java!

> 1000.lies
"Java is 1000 times more fun than Ruby!"

You see the principle of least surpries applies here, too :)

to_s is being used when you want to interpolate an object into
a string, as above in the lies method. When you define a to_s
method though and wonder why irb keeps ignoring it, well, what
is being printed when it should put out something's return value
is its inspect method.

-Martin :)