From: harryo@... (Harry Ohlsen)
Date: 2001-04-23T20:40:04+09:00
Subject: [ruby-talk:14073] Re: RCR: getClassFromString method

>You could simply use an eval:
>
>  module ObjectSpace
>    def ObjectSpace.class(name)
>      eval(name)
>    end
>  end

Thanks for that.  I think that's much nicer than mine.

>You might want to add some error checking:
>
>
>  module ObjectSpace
>    def ObjectSpace.class(name)
>      return nil if not (validClassname?(name) and eval(name).kind_of? Class)
>
>      eval(name)
>    end
>
>    def ObjectSpace.validClassname?(name)
>       name =~ /^[A-Z][a-zA-Z0-9]*$/
>    end
>  end

I'm not sure why you do the check on the validity of the class name. I
assume it's because otherwise the eval would throw an exception?

>If you are concerned about performance you could remove the doubled
>eval, but then again if you are concerned about performance you should
>implement it native anyway.

In my case, I'm not all that worried about the performance, but I
would guess other people might be.

I'm using this to allow me to write "new Fred(...)" rather than
"Fred.new(...)", and that's only because I keep making the mistake of
using the former rather than the correct syntax, because I've been
writing C++ and Java for far longer than I have Ruby.

The other reason I wanted to do it was because I just wondered if I
could.  I should have known it was possible, because, after all, this
is Ruby !!