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.
