From: khaines@...
Date: 2006-07-29T07:33:08+09:00
Subject: Re: Puts bypasses access restrictions on to_s?

On Sat, 29 Jul 2006, Leslie Viljoen wrote:

> See here:
>
> irb(main):005:0> class RiseAndShine
> irb(main):006:1> private
> irb(main):007:1> def to_s
> irb(main):008:2>   "rising and shining"
> irb(main):009:2> end
> irb(main):010:1> end
> => nil
> irb(main):011:0> rs = RiseAndShine.new
> => rising and shining
> irb(main):012:0> rs.to_s
> NoMethodError: private method `to_s' called for rising and 
> shining:RiseAndShine
>       from (irb):12
> irb(main):013:0> puts rs
> rising and shining

irb(main):008:0> rs.__send__(:to_s)
=> "rising and shining"

Ruby lets private be circumvented.

To see how puts really works, though, take a look at the source code. 
It's pretty easy to read.  Look in io.c for rb_io_puts().  Start from 
there.


Kirk Haines