Note that an empty string is equivalent to a 'false' value, while a populated one is 'true' (unless it evaluates to a numeric zero). You can also get rid of your !'s by reversing your AND/OR tests and negating the original terms: 
sub chkfmt {
   if ((!$DISCPCNT || !$DISCDAYSDUE || !$NETDAYSDUE || $NETDUEDATE || 
+$TERMSDISCAMT) ||
       (!$DISCDUEDATE || !$TERMSDISCAMT || $DISCPCNT || $DISCDAYSDUE |
+| $NETDUEDATE || $NETDAYSDUE) ||
       (!$DISCPCNT || !$DISCDUEDATE || $DISCDAYSDUE || $NETDUEDATE || 
+$NETDAYSDUE || $TERMSDISCAMT))
   {
      print TSERROUT "...";
   }
}

[download]
Note that with all of these negation reversals in my head, I might have messed up your original logic. Take a look at that and see if you can follow it, making corrections as appropriate. Even if I got everything right in the translation, the code above still may not match what you're wanting if your original code was broken to begin with. Hope this helps.

In reply to Re: Set Combination by Fastolfe
in thread Set Combination by Anonymous Monk

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