You can use &MAXCC with &LASTCC to determine error conditions. For example, error codes caused by evaluation errors are in the 800-899 range. You can modify the error routine in the example under &LASTCC to determine first whether the error was caused by an arithmetic evaluation. Insert the following IF-THEN-ELSE sequence before the check for character data in operands:

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/* Evaluation error?           */
   IF &MAXCC <800 OR &MAXCC >899 THEN + 
      GOTO …
   ELSE + 
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