From: Michael Neumann <neumann@...>
Date: 2001-09-05T20:44:17+09:00
Subject: [ruby-talk:20920] Re: RCR: non-bang equivalent to []=

Florian G. Pflug wrote:
> > But this will not be compatible. Array#delete, #fill and all the others 
> > must be changed to the bang version. Any change to existing method names
> > will break code. A  solution would be to introduce #delete! etc..
> > that are just an alias to #delete. But this would break IMO PoLP. 
> 
> I think, you either
> 	1) See the bang as a help, especially in situations where is is not clear.
> 		that array#delete_at modifies the receiver is quite clear I think.
> 	2) See it as a part of the languages syntax. Then is should be enforced by
> 		the interpreter.
> 
> I prefer the opinion 1).

me, too.

> However, the change _would_ be possible.
> 
> One would have to define two include files, ruby_old and ruby_new.
> 
> First, ruby_old would be an empty file, and ruby_new would change the array
> class (and perhaps other classes) accordingly.
> 
> After the change is done in ruby itself, ruby_new would be empty, and
> ruby_old would restore the previous behaviour.
> 
> Of course, when phase two is reached, code breaks. But by then, everyone has
> hd the change to either fix his code, or add a "require 'ruby_old'" at the
> beginning of each file.

This would IMHO not work in all situations.
Imagine you use an old library using "ruby_old" implicitly. But in your program you use
the "ruby_new". What happens if you pass an Array from your program to the old library,
and this calls Array#delete or something else? Would it break? Yes it would, because 
there's only one Array class, unless your new program uses a class named e.g. NewArray.
 

Regards,

  Michael


-- 
Michael Neumann
merlin.zwo InfoDesign GmbH
http://www.merlin-zwo.de