Thanks for the reply, Philip.
Dropdown boxes are cumbersome visually and ergonomically for the user
and I would rather not go there.
If I have a pair of grouped Ruby generated radio buttons, then
following are the initial possibilities or states:
false - false (in which case presumably a null is returned)
false - true (returns a 0)
true - false (returns a non-zero)
It appears that some ivory towered radio button designer never
conceived that a user might click on a radio button group, change
their mind and want to undo the click therefore returning to a false-
false state. Some languages providing for a user interface have
caught on, some haven't.
Is it perhaps possible to do this by grouping a couple of checkboxes
and set then them up so that the user can select either one or none??