st: dialog program: make LISTBOX initially hidden or use repopulate?

[Jonah Sol Gabry <jsg2201@columbia.edu>]

Hi all,

I'm trying to find the best solution to the following dialog
programming problem:

I have two list boxes and I would like the entries in LISTBOX 2 to
change depending on which entry in LISTBOX 1 is selected. Two
different possible methods occurred to me but I'm not quite sure how
to accomplish either of them or if they are even possible. For
simplicity, suppose LISTBOX 1 offers only two possible selections, a
and b (although there will be many more in reality).

Method 1: use onselchangelist() to specify how LISTBOX 2 should be
repopulated depending on whether a or b is selected in LISTBOX 1. But
I'm having trouble figuring out how to use the repopulate member
function in this way.

Method 2: get rid of LISTBOX 2 and instead have LISTBOX 2a and LISTBOX
2b. The idea would be that both of them would be hidden by default and
then shown depending on whether entry a or entry b in LISTBOX 1 is
selected. Below is some simplified code along the lines of what I
imagine this would look like (except I don't know how to specify that
LISTBOX lb_list2a and LISTBOX lb_list2b should be hidden by default).

Thank you in advance for any advice. It's greatly appreciated!


CODE:

*here are the list boxes:
LISTBOX lb_list1 . . . . ,  ///
 contents(list1_contents) ///
 onselchangelist(list2show)

LISTBOX lb_list2a . . . . ,  ///
 contents(list2a_contents)

LISTBOX lb_list2b . . . . ,  ///
 contents(list2b_contents)

*here's a list containing the iactions corresponding to onselchange(list2show)
LIST list2show
 BEGIN
main.lb_list2a.show
main.lb_list2b.show
END

*here are the lists with the contents for the list boxes
LIST list1_contents
BEGIN
a
b
END

LIST list2a_contents
BEGIN
item1
  item2
item3
item4
END

LIST list2b_contents
BEGIN
item1
  item4
END

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