From: mental@...
Date: 2006-01-25T08:50:08+09:00
Subject: Re: LazyLoad

Quoting Erik Veenstra <google@erikveen.dds.nl>:

> Yeah, true. Bad example. The original code (the branches) uses
> a common method "load" which sets both properties. If one of
> them is used, the other gets set as well. No problem there.

Actually there is a problem the moment such an instance variable is
assigned to another variable or passed as a parameter.  The
LazyLoad instance escapes the block's control.

 class Example
   def initialize
     @prop = LazyLoad.new { @prop = [1, 2, 3] }
   end
   def show3
     helper( @prop )
   end
   def helper( arr )
     p arr.pop
     p arr.pop
     p arr.pop
   end
 end

 ex = Example.new
 ex.show3

What would you expect this program to output?  What actually
happens?

-mental