(pure intellectual masturbation ;)

$\="\n";$,="\t";
{
  package SAS;
  our ($ini,$last);
  sub _1 {$ini-$last}
  sub _2{$last-$ini}
  sub _3 {$ini-$last}
}
 
 
$SAS::ini=4;
$SAS::last=2;
 
print &SAS::_1, &SAS::_2 , &SAS::_3;
[download]

 
package SAS2;
our ($ini,$last);
sub _1 {$ini-$last}
sub _2{$last-$ini}
sub _3 {$ini-$last}
 
package main;
 
 
$ini=10;
$last=5;
  
print SAS2::_1(), SAS2::_2(), SAS2::_3();
[download]

If you really need a hash like structure you may wanna try investigate the %SAS:: hash to grep all functions starting with an underscore.

print map {$_->()} grep {/::_/} values %SAS::;
[download]

of course this map-grep operation could be a method of your object ...

UPDATE: expanded code examples