From: Wes Gamble <weyus@...>
Date: 2006-05-18T02:20:17+09:00
Subject: Re: Dynamically modifying modules to avoid namespace collisi

Greg,

How does this

str.to_s.split("::").inject(Object) { |ns,name| ns.const_get(name) }

work?

Wes

Gregory Seidman wrote:
> On Wed, May 17, 2006 at 09:34:34AM +0900, Logan Capaldo wrote:
> [...]
> } One does not require modules, one requires files. One file may have
> } many modules in it, or none. Regardless one can still 'require' that
> } file.
> }
> } One way to hack something so it gets stuck in a module is:
> }
> } module Protect
> }   eval(File.read("path/to/file.rb"))
> } end
> }
> } Then you access all the classes defined in file.rb like:
> }
> } Protect::Node.new # etc.
> 
> This is a great idiom, but it needs to be able to function as a (nearly)
> drop-in replacement for require. This means that I need to be able to 
> find
> the file in the search path that require would normally use. Consider 
> the
> following:
> 
> def find_require_file(filename)
>   # NEED IMPLEMENTATION HERE
> end
> 
> def namespace_get(str)
>   str.to_s.split("::").inject(Object) { |ns,name| ns.const_get(name) }
> end
> 
> def require_within(module_name, filename)
>   file = find_require_file(file)
>   mod = module_name
>   case module_name
>     when Module,Class
>       #noop
>     else
>       mod = namespace_get(mod)
>   end
>   mod.instance_eval { eval File.read(file) }
> end
> 
> This is untested, and I don't know how to implement that 
> find_require_file,
> but the idea is that the following should work:
> 
> module Foo
>   module Bar
>   end
> end
> 
> require_within Foo::Bar, "date"
> 
> x = Foo::Bar::Date.today
> 
> Anyone want to implement find_require_file and test the idea?
> 
> --Greg


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