Re: [Fxruby-users] connect oddity?

[Joel V. <vj...@us...>]

Fredrik Jagenheim wrote:
> Hi,
> 
> I tried using connect like this:
> 
> 8<
> 
> j = 0
> 3.times { |i|
>   FXButton.new(self, "Button#{j}").connect(SEL_COMMAND) { 
>     puts "#{j} pressed"
>   }
>   j += 1
> }
> 
> 
>>8
> 
> 
> This doesn't work as intended, but if I use the 'i' variable, it does.
> I figured it had to do with global/local scope, but I don't grok it
> fully.

As you guessed, it's not particularly an effect of #connect. It has to
do with the way ruby associates bindings with code blocks. Your code
generates three closures (closure=code+binding) of the block

   {
     puts "#{j} pressed"
   }

and all three of them refer to the same j variable. The string isn't
interpolated until you execute the code. By the time the code executes
(when you press a button), the value of j is 3. So a "3" gets
interpolated in all three strings.

I didn't run the code (so I may be completely wrong ;) ), but I've been
bitten by this before.

Using just "i" instead of "j" is one way around, as you noticed. Another
way is to assign the value of j to a new local variable ("k", say)
inside the #times block, and use that in the string interpolation.

HTH.