Request to add attribute hideSubOnNoRecords to the BOX-template TABLE

[RieksJ]

The BOX-template FORM has an attribute hideSubOnNoRecords, the functionality of which is that rows inside the FORM only show if there is something to show. This is easy to compute: whenever the expression for that row does not produce a TGT atom, there is nothing to show. The BOX-template TABLE does not have this attribute, because the computation that would work in all cases is quite difficult and would require lots of expressions to be computed.

However, there is a particular type of use-cases where computations are easy. That is when the TABLE template is used as a means to show a sequence of elements for a single atom. Examples include a button-bar (for the current SESSION-atom), a status bar (for the current form in which you are working), or a line that shows a persons name, and only a phone number or email address if that has been specified.

This issue requests that the attribute hideSubOnNoRecords will become available in the BOX-template TABLE, with the following semantics:

• when there is more than one TGT atom on the expression of the BOX itself (indicating that the table would have more than one row), an error is thrown;
• when the expression of a column does not have a TGT atom, the column is not displayed.