From: Logan Capaldo <logancapaldo@...>
Date: 2006-06-12T04:26:17+09:00
Subject: Re: ... building my own end-fix statements.


On Jun 9, 2006, at 4:44 PM, Jeff Wood wrote:

> I believe it's possible to define my own end-fix qualifiers like "if"
> and "unless" ...
>
> Can anybody provide code examples for defining such a construct in  
> Ruby?
>
> For instance :
>
> x.doSomething() when x.ready?
>
> which would call x.ready? repeatedly until it returned a true then
> would call x.doSomething()
>
> ... I know I could do
>
> while( not x.ready? )
> sleep 0.5
> wend
>
> x.doSomething()
>
> but I'd rather not.
>
> even a
>
> when( x.ready? ) { |result| x.doSomething() } would be fine I guess
> ... but wouldn't work because x.ready? would be precalculated before
> when gets to it... so it wouldn't ever change... I basically need to
> be able to pass two blocks if I were to do this ...
>
> when( isReadyProc, bodyProc ) ... or something like that.
>
> Any ideas ???
>
> --jw.
>

I called it "after" since when is a keyword:

% cat after.rb
class After
   def initialize(&block)
     @test = block
   end

   def do
     until @test.call
       sleep 0.5
     end

     yield
   end
end

module Kernel
   private
   def after(&block)
     After.new(&block)
   end
end

class X
   def initialize
     @x = 0
   end

   def ready?
     if @x == 10
       true
     else
       @x += 1
       false
     end
   end
end

x = X.new
after { x.ready? }.do {
   puts "x is finally ready!"
}





% ruby after.rb
x is finally ready!