I usually prefer to keep the scope levels in mind. Because perl doesnt have a defined main block and some of the subtler uses of scope (anonymous blocks for instance) and BEGIN{} END{} blocks I try to keep things organised so its intuitive. For instance

#!perl
# GLOBAL DEFINITIONS
# TYPEGLOBMANIPULATIONS
# BEGIN{}
# FUNCTIONS
# ANON_BLOCKS
# END{}
# main() equivelent.
__DATA__
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Because this kind of thing can get confusing:

my $var;
sub foo {$var++; #ie code}
my @list;
use Some::Class;
sub bar{}
my %hash;
sub sna{}
sub fu{}
my $scalar;
# code
# ....
__DATA__
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Now you might say "what if a lexical variable is used only by one particular funct ie static lexical" well then I usually do something like this

{ #Anonymous block for the following static lexicals:
  my $static_scalar;
  my @static_array;
  sub push_stack { push @static_array,@_}
  sub pop_stack  { pop @stack}
} #End anonymous block
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So the first would probably end up like this:

use Some::Class;
sub sna{}
sub fu{}
{
   my $var;
   sub foo {$var++; #ie code}
}
{
  my @list;
  sub bar{}
}
my $scalar;
my %hash;
# code
# ....
__DATA__
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Much easier to figure out whats gone 12 months later i assure you. Yves