From: "David A. Black" <dblack@...>
Date: 2005-02-01T04:42:04+09:00
Subject: Re: Should every method have a module method?

Hi --

On Tue, 1 Feb 2005, Trans wrote:

> I'm looking at some the Rail's support methods to see what Facets can
> gain from it. The following gives me pause (slightly simplified for
> your inspection):
>
> | module Inflector
> |   extend self
> |
> |   def pluralize(word)
> |     result = word.to_s.dup
> |     plural_rules.each do |(rule, replacement)|
> |       break if result.gsub!(rule, replacement)
> |     end
> |     return result
> |   end
> |   ...
> |
> |
> | class String
> |   module Inflections
> |     def pluralize
> |       Inflector.pluralize(self)
> |     end
> |   ...
> |
> | class String
> |   include Inflections
> | end

(Small request: can you not put | at the beginning of code lines?  It
makes them hard to cut-and-paste.  Just indenting is fine.)

> Is all this really neccessary? Are these methods really ever usful for
> anything else but Strings and derivatives thereof? --What would you
> include them in? And would you ever really be more inclined to write:
>
> Inflector.pluralize(a)
>
> over
>
> a.pluralize
>
> Perhaps some people use Ruby in completely non-OOP ways. I guess they
> would appriciate this design. If so should that be something we should
> always try to accomodate?

It's not strictly a OOP/non-OOP thing; it's a clash thing.  It's the
same old "prisoner's dilemma"-esque problem as always: if we all agree
on what core changes can be made dynamically, we can make them, but if
we don't, we can't safely make any.

This was one of the first things I worked on when I got interested in
Ruby, and the result was the almost-proof-of-concept project Ruby
Behaviors, which offered a mechanism for block-scoped changes to the
core language.  It wasn't thread-safe, though.  There are some other
similar packages that do similar things, one of which I believe is
thread-safe.  And Matz has been talking about some kind of namespace
facility in Ruby 2.0 to allow for this kind of thing too.


David

-- 
David A. Black
dblack@wobblini.net