How To Add A REQUIRED Clause to a VALID
                      Using TL_FORM.GEN
                          Tony Lima
                       August 19, 1990

DISCLAIMER

This template is provided as-is.  The author, Tony Lima, will
not be responsible for any damage it may cause.

PURPOSE

To allow users to add the keyword REQUIRED to a VALID clause
of an @ ... GET from the screen form designer.

USAGE

To add a REQUIRED, insert the following in the "Accept data
when" area of the Edit options menu of the screen form
designer:

    'REQ'='REQ' .AND. <rest of logical condition>

Note that this must appear exactly as shown above.
Specifically, the letters REQ must be enclosed in SINGLE
QUOTES (') and the <rest of logical condition> must begin in
position 19 in the string.

RATIONALE

dBASE IV 1.1 makes a subtle but important change to the nature
of the VALID clause used with @ ... GET's.  In version 1.0, no
data was allowed in a field that did not meet the condition(s)
specified by the VALID.  This applied to data that may have
been entered before the VALID was added to the FMT file.
Thus, if a record was edited that contained this data, it
would have to be corrected before the record would be
accepted.

In version 1.1, use of a VALID with nothing else will allow
data to violate the VALID condition.  If <Enter> is pressed
with no changes made to the data, the VALID will not be
enforced.  In order to have the VALID enforced in all records,
the keyword REQUIRED must be added between the VALID and the
logical condition that is its object.

The problem is that the screen form designer was not modified
to reflect this new usage.  However, the FORM.GEN template can
be fairly easily changed to accomplish this.  That is the sole
purpose of TL_FORM.GEN:  to allow the addition of a REQUIRED
clause to a VALID without programming.

For more information, see the file header of TL_FORM.COD.