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Using and renaming same variables/hash within different subroutines,

 

Using and renaming same variables/hash within different subroutines,
Sun751

24 Jun, 2009 - 12:14 AM
Post #1

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I am writing Perl script for my project, where I am passing same variable to different sub routine with different name so that it won’t collide with same variable within another subroutine,

Though, the variable holds same value due to continuous renaming in different subroutine its getting bit confusing and looks like bit of mess , for example,
CODE

my (%resource,$portoffset);

initialize(\%resource,$portoffset);
consolidate(\%resource, $portoffset);
dispatch(\%resourcel,$portoffset);


sub initialize
{
    my ($HRI_resource,$I_portoffset) = @_;
}

sub consolidate
{
  my  ($HRC_resource, $C_portoffset)= @_;
}

sub dispatch
{
my  ($HRD_resource, $D_portoffset)= @_;
}

Any one have any suggestion regarding this? Please let me know.

Cheers
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dsherohman

RE: Using And Renaming Same Variables/hash Within Different Subroutines,

24 Jun, 2009 - 05:42 AM
Post #2

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Lexically-scoped variables (i.e., those defined using "my") don't exist outside of the block where they're defined, so you don't actually need to use different names. Running the code:
CODE
#!/usr/bin/perl

use strict;
use warnings;

first();
second();

sub first {
  my $x = 1;
  print "first: $x\n";
}

sub second {
  my $x;
  print "second: $x\n";
}

produces the output
CODE

first: 1
Use of uninitialized value in concatenation (.) or string at foo.pl line 16.
second:


As you can see, the $x in second() is uninitialized even though $x was set to 1 in first(). They are completely separate variables which do not interact with each other at all, despite having the same name, because each is confined to a different scope.

For a more thorough discussion of the topic, see MJD's Coping with Scoping and, in particular, the "Lexical Variables" section.
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