#!/bin/perl -w
use strict;

use Memoize;
memoize('rvg');                           # now all calls to rvg are memoized

my @rnd_names= qw( foo bar baz);

$/="";
while(<DATA>) {
s/(?<!\\)(\$\w+(?![\[{\w]))/rvg($1)/ge;  # need to add $1 for memoize to know which calls to memoize
print;
}


sub rvg
  { return shift @rnd_names; }
  
__DATA__
$v1= $v2;
$v2++;
$v3{$v1}= $v2;