From: Stephen White <steve@...>
Date: 2000-12-23T00:23:44+09:00
Subject: [ruby-talk:7952] Re: defined? problem?

On Fri, 22 Dec 2000, David Alan Black wrote:

>    irb(main):003:0> if m then m = 123 end
>    NameError: undefined local variable or method `m' for #<Object:0x4017fc90>
>    (irb):3:in `irb_binding'
>    irb(main):004:0> if m then m = 123 end
>    nil

That's a good one!

> This feels like a rather dramatic (for Ruby) compile-time vs. runtime
> contrast.

What we're seeing here is the effect of Ruby's complex grammar affecting
how quickly instructions can be resolved. By the time it's worked out the
word "then" isn't a procedure with arguments, it's already gotten up to
and resolved "m = 123". This means that Ruby's interpreter allows out of
order resolution of code, possibly as a speed optimisation.

Without looking at the code, that'd be my guess. :)

-- 
  steve@deaf.org