From: Joel VanderWerf <vjoel@...>
Date: 2006-03-04T09:41:16+09:00
Subject: Re: require just in a context?

E. Saynatkari wrote:
> cap wrote:
>> Can I make some libraray just work in a context ?
>>
>> I add a new ruby file into my app using "require 'mathn'" but i don't
>> want every ruby file to use the 'mathn', how can I do it?
> 
> Well, anytime you call #require, the effect will be global.
> You can delay the call until a certain point in your program
> (possibly useful if there is a possibility that it would not
> be loaded at all) since #require is just a method. For example,
> 
>   def foobar(x, y)
>     require 'mathn'
>     # ...
>   end
> 
> Would be fine (but would still have an effect just like if
> you did it at the top of the file).
> 
> As an alternative, you could wrap the loaded file into a
> module either using #load which can use an anonymous module
> (see the docs) or a library such as Script (see RAA) which
> uses a named module. This approach might not work with mathn
> or anything else that modifies existing classes.

Nope. If you Kernel#load or Module#module_eval a file which requires
mathn, the effect will still be global.

$ ruby -e 'load "foo.rb"; p 1/2'
1/2
$ ruby -e 'm=Module.new; m.module_eval(File.read("foo.rb")); p 1/2'
1/2
$ ruby -v
ruby 1.8.4 (2005-12-24) [i686-linux]

I think what you want is something called behaviors. See the list
archives...

-- 
      vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407