From: David Alan Black <dblack@...>
Date: 2004-04-14T21:34:23+09:00
Subject: Re: New Local Variable Scope rule

Hi --

ts <decoux@moulon.inra.fr> writes:

> >>>>> "D" == David Alan Black <dblack@wobblini.net> writes:
> 
> D>   def call_foo
> D>     foo(lambda{|b| c=b})
> 
> D>     puts c                # does c persist if the lambda was called?
> D>   end
> 
>  What you have written is similar to
> 
>    def call_foo
>       a = lambda {|b| c = b}
>       foo(a)
>       puts c
>    end
> 
>  foo(a) don't change anything and if I've well understood : this is at
>  compile time that ruby will make the decision (local/block-local)

OK... but what will the decision be, for 'c'?  Why would it be any
different here than for:

  def foo
    [1].each { c = 0 }
    puts c
  end

In both cases, an assignment is being made to c, visible at compile
time, in a particular scope.  So, in your example (and mine), c is
created at compile time in the calling scope (call_foo).  Then the
lambda is called, and c is actually assigned something.  

Or is there going to be a further distinction between plain lambdas
and code blocks passed to iterators?  If so, I really think it's time
for a Block class.  (Matz: you wanted more reasons.... :-)


David

-- 
David A. Black
dblack@wobblini.net