#!/usr/bin/perl

# http://perlmonks.org/?node_id=1172192

use strict;
use warnings;

while(<DATA>)
  {
  print;
  s/(nr\d+)(?{"calc($1);"}) | (\d+)(?{4 * $2}) /$^R/gx;
  print;
  }

__DATA__
hello nr34,nr56,78, 98 , hi, 76