Re: [MacPerl] Callbacks not reliable?

[Keary Suska <aksuska@insideflyer.com>]

The problem/quirk I am noticing can be shown with the following change to
Chris's code below:

  #!perl -wl
  $_ = 1;
  foo(1);  # 1
  foo(2);  # undef
  /(1)/; print $1;  # 1
  /(2)/; print $1;  # 1
  foo(2);

  sub foo {
     /($_[0])/;
     print $1;
  }

I would think that the $1 in Main is in a different scope than the $1 in
foo. But this does not necessarily seem the case...

-K

"Do not meddle in the affairs of dragons, because you are crunchy and taste
good with ketchup."


> From: Chris Nandor <pudge@pobox.com>
> Date: Thu, 14 Sep 2000 19:07:50 -0400
> To: Ronald J Kimball <rjk@linguist.dartmouth.edu>
> Cc: Keary Suska <aksuska@insideflyer.com>, MacPerl_List <macperl@macperl.org>
> Subject: Re: [MacPerl] Callbacks not reliable?
> 
> At 18:35 -0400 2000.09.14, Ronald J Kimball wrote:
>> On Thu, Sep 14, 2000 at 03:31:49PM -0600, Keary Suska wrote:
>>> I had always thought in m// or s/// that if the pattern doesn't match that
>>> the callback variables (i.e. $1, $2, $3 ...) would be undefined. I am
>>> finding that this isn't the case at least with a substitution.
>> 
>> That is incorrect.  $<digit> and the other regex special variables contain
>> the values from the last *successful* pattern match in the current scope.
>> An unsuccesful match does not reset these variables.
> 
> But these variables are automatically local()d to the enclosing block, I
> think:
> 
> #!perl -wl
> $_ = 1;
> foo(1);  # 1
> foo(2);  # undef
> /(1)/; print $1;  # 1
> /(2)/; print $1;  # 1
> 
> sub foo {
> /($_[0])/;
> print $1;
> }
> 
> -- 
> Chris Nandor                      pudge@pobox.com    http://pudge.net/
> Open Source Development Network    pudge@osdn.com     http://osdn.com/


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