When expressions are evaluated by REXX

Expressions specified on the FORM.CALC panel and used as substitution variables (&CALCn) in text areas of the form are passed to REXX for evaluation at different times, depending on where they are placed in the form.

• Calculations are processed when they are formatted:
  • References on FORM.DETAIL panels with SELECT=NO or SELECT=Cn (where n condition is false) are not evaluated.
  • If the calculation is listed on separate lines in one variation, it might be evaluated multiple times.
  • If the calculation is referenced on several selected FORM.DETAIL variations (in which the Select Panel Variation field is YES or Cn, where condition n is "true"), the calculation might be evaluated multiple times.
• Expressions specified on the FORM.CALC panel and used as a usage code on the FORM.COLUMNS panel are evaluated by REXX whenever the value is needed for formatting.
• Expressions specified on the FORM.COLUMNS Definition panel to define a new column are evaluated by REXX each time a row is fetched. Rows can be fetched more than once (for example, to support printing a report in which page-splitting is required) or to support a usage code (such as TCPCT) that requires all the data to be retrieved first.
• Expressions specified on the FORM.CONDITIONS panel and referred to on a FORM.DETAIL panel variation are evaluated by REXX at least once for every detail row formatted in a report.