Re: What’s the best way to check if a feature/class has been loaded?

On Wed, Mar 21, 2012 at 9:51 PM, Nikolai Weibull <[e-mail]> wrote:

There=E2=80=99s a timing issue with using const_defined? followed by const_=
get
> instead of calling const_get directly and catching NameError.


What do you mean?

The problem with const_get is that it follows the ancestors, of course, and
you have no way around that in 1.8.


I guess
>
> def feature?(path)
>   path.split('::').reduce(Object){ |o, e|
>      c =3D begin o.const_get(e); rescue NameError; return nil end
>     return nil if c =3D=3D (o !=3D Object and begin Object.const_get(e);
> rescue NameError; nil end)
>     c
>   }
> end


Nikolai, I don't really understand what you need. You are askind for
defined? X::Y that goes step by step and your original code does raise an
error for X::Y integer.

Then this second version cannot say that X::Y is defined in

    module X
      Y =3D nil
   end

And you refuse to reuse much more simple and proven existing solutions.

You want something with so special semantics that definitely is NOT
built-in. That answers you original question.

Good luck!