#!/usr/bin/perl

        for (;;) {
          print "Gen = ", Gen_val(), "\n";
          my @code = source_of_function('Gen_val');
          for (@code) {
            last if s{(\d+)(?=;\s+\# EDIT ME)}
                     {(($1 * 1103515245 + 12345) / 65536) % 32768}e;
          }
          eval join '', @code;
        }

        sub Gen_val {
          1;     # EDIT ME
        }