From: gwtmp01@...
Date: 2006-02-10T04:54:21+09:00
Subject: Re: Method Definitions: &block vs. yield()


On Feb 6, 2006, at 6:03 PM, Joel VanderWerf wrote:
> But with yield, you can only call the block from within the scope  
> of the method. If you need to store it away somewhere and call it  
> after returning, then you have to use a Proc.

You can pass an implicit block to another method by wrapping it in
another block:

class Example

   def m1
      m2 { yield }
   end

   def m2
     yield
   end

end

e1 = Example.new

e1.m1 { p 42 }

There is no explicit reification of a block to a Proc object
in this example.  This technique can avoid the creation of
a Proc object in many common situations, but certainly not
in all cases.


Gary Wright