From: Victor Shepelev <vshepelev@...>
Date: 2006-04-28T11:22:00+09:00
Subject: Re: nil? takes much time

> > In one my class I've had very simple method:
> >
> > ...
> > def stored?
> >   !@db.nil?
> > end
> > ...
> >
> > And I've suddenly noticed (due to profile) that nil? Takes a
> > significant
> > amount of time here.
> >
> > Redefining the above method like
> >
> > def stored?
> >    @db
> > end
> >
> > (in if's it works good) speedups the entire program.
> >
> > I'm a bit surprized :)
> >
> 
> If you think about it, it's not all that surprising. false and nil
> are both immediate values, this means its very quick to check if
> something is not false or nil and therefore true. .nil? sends a
> message. Sending a message involves

[skip]

From one side, you are right (and I've must understand all above in myself).
What is really unpleasant - is to see how can "infrastructure" code slow
down the program. The effect "nil? is slower then direct if" is waitable.
What is UNwaitable - that nil? is *noticable* slower (in profile report it
was fifth line from top). I hope thing would go better in next ruby's
version.

Offtopic: BTW, can somebody comment on following questions:
1. How much 1.9 faster than 1.8.4, and how much it stable?
2. When can we wait for Rite?

Thanks.

Victor.