Global/Local variable 1

[ejaggers]

I'd like to save a value in $LastValue, but don't want it to be global, or disappear when I exit the subroutine like my $LastValue. Is there such a type that will stay set but is not global?

 

[rharsh]

Probably the easiest way is to return the value you want to keep from the sub. There's not much context, so it's hard to tell.

A quick example:

my $last_value = mysub();
print "Value from sub: $last_value\n";

sub mysub {
  # do stuff
  return $value;
}

 

[ejaggers]

rharsh, what I mean is:

sub xyz {
my $x = shift;
$x = $Last_Value unless $x;
$Last_Value = $x;
...

return;
}

Is there a way to save $Last_Value in sub xyz, without making it global to all?

 

[Kirsle]

I don't believe this is possible and it was one of the things Perl 6 is going to address.

What you could do is create a unique package for your subroutine and use it as a class-level variable.

i.e.

package MyXYZ;

use Exporter;
@EXPORT = ("xyz");

our $Last_Value = 0;
sub xyz {
   # ...whatever
   $Last_Value = $z;
}

package main;
use MyXYZ;

# continue your main code here

print "last value: $Last_Value\n"; # shouldn't work
xyz ($whatever);
print "last value: $Last_Value\n"; # shouldn't work
print "again: $MyXYZ::Last_Value\n"; # if you really really want it

If you don't like mixing multiple packages in the same source file you can save it like a Perl module.

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[prex1]

What follows should be the solution to your problem:

{my$Last_Value=...;
  sub xyz {
    my $x       = shift;
    $x          = $Last_Value unless $x;
    $Last_Value = $x;
    ...
  
    return;
  }
}

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[ejaggers]

Thanks perx1, I've been using globals all over the place. This is a BIG help!!!