[ruby-core:35579] Re: Stupid Question 999.9!!

On 3/29/2011 2:58 AM, Charles Thornton wrote:
> OK, Stupid Question 999.9
>
> What is the reason for this IF Block?
>
> It is an example from FXRuby! It seems
> to have no purpose other than being an
> unconditional IF Statement.
>
> if __FILE__ == $0
>    FXApp.new do |app|
>      HelloWindow.new(app)
>      app.create
>      app.run
>    end
> end

It's not unconditional. It executes if $0 is equal to the file. $0, if 
you check, is equal to the script initiated via a ruby process, ie. ruby 
myscript.rb => $0 == "myscript.rb".

In other words, it executes when the script is executed directly and not 
when part of a require/load.

It's the same as the Python convention of:

     if __name__ == '__main__':
       # ... script is being run directly ...

- Loren