From: "David A. Black" <dblack@...>
Date: 2005-09-06T07:56:34+09:00
Subject: Re: Change Binding of a Proc

Hi --

On Tue, 6 Sep 2005, Trans wrote:

>
> Trans wrote:
>> Now that seemed like a really smart solution --but when I try it I get
>> some really STRANGE behavior. In my code @start is assign to one of the
>> procs, so then:
>>
>>   s = @start
>>   p s
>>   p s.call
>>   p machine.instance_eval{ s }
>>   p machine.instance_eval{ s.call }
>>   p machine.instance_eval{ s.call.call.call }
>>
>> returns
>>
>>   #<Proc:0xb7cf868c@state_parser.rb:140>
>>   #<Proc:0xb7cf868c@state_parser.rb:140>
>>   #<Proc:0xb7cf868c@state_parser.rb:140>
>>   #<Proc:0xb7cf868c@state_parser.rb:140>
>>   #<Proc:0xb7cf868c@state_parser.rb:140>
>
> er...
>
> irb(main):001:0> start = 10
> => 10
> irb(main):002:0> start = lambda { start }
> => #<Proc:0xb7b2f700@(irb):2>
> irb(main):003:0> start.call
> => #<Proc:0xb7b2f700@(irb):2>

That's because your lambda is a closure.  It respects the binding of
start, which you've (re)bound to the lambda itself.


David

-- 
David A. Black
dblack@wobblini.net