From: matz@... (Yukihiro Matsumoto)
Date: 2003-02-02T23:40:26+09:00
Subject: Re: Local variables & blocks

Hi,

In message "Re: Local variables & blocks"
    on 03/02/02, Brian Candler <B.Candler@pobox.com> writes:

|On Sun, Feb 02, 2003 at 01:50:05PM +0100, ts wrote:
|>  What do you do with Thread and Proc which *need* block local variables ?
|
|Hmm. ISTM that if this is a problem, it will affect Matz's [63100] as well.

No.  Unlike yours, mine still has sort of block local variabls.

|I just re-read the Pickaxe section on threads, and yes I agree - and I also
|think it's a mess. When you assign to 'x' within a block, it has two
|entirely different behaviours, depending on whether 'x' was in existence
|previously or not.

I agree with you.  I was insane when I designed this rule.  That's why
I propose the change.  But I don't think we can just drop block local
variables like yours, since we have Proc (some kind of anonymous
function), we need some kind of local variables of their own.

|Now, as for Procs, I haven't used them much but I suppose the same sort of
|thing applies:
|
|  i = 1
|  ...
|  a = Proc.new { |x| i = x+x; i }    # 'i' is some intermediate variable

Unfortunately, this doesn't work for closures.  In a plain words,
global variables (from the viewpoint of a Proc) can not always replace
local variables.

							matz.