tab_stack.md
In rswipl: Embed 'SWI'-'Prolog'

class tab_stack {#class-tab_stack}

A tab_stack object controls a set of tab objects, sheets holding controllers. Tab-stacks are normally used to make dialog windows with large numbers of options manageble.

The code below is a partial implementation of a dialog to specify a PC:

new(D, dialog('PC Specifiation sheet')),
send(D, gap, size(0,0)),
send(D, pen, 0),
send(D, append,
     tab_stack(new(CPU, tab(cpu)),
               new(Disk, tab(disk)),
               new(Monitor, tab(monitor)),
               ...)),
send(CPU, append,
     new(CPUT, menu(cpu, choice))),
send_list(CPUT, append, [386, 486, pentium]),
...

send(D, open).

tab_stack->append: tab Append a tab object to the right of the member tabs. If it is the first tab, it will become the one ->on_top. Tabs may be added both before and after displaying a tab_stack. See ->layout_dialog for fixing the layout after adding to a displayed tab_stack.
tab_stack->erase: graphical Erases a tab object or graphical from the tab-stack. Ensures another tab is raised if this is the <-on_top tab and recompute the layout of the tabs. See also device->erase.
tab_stack->initialise: member=tab ... Create a tab-stack holding the argument members. The arguments are handed to ->append, left to right.
tab_stack->layout_dialog: [size] This method is normally called by the generic dialog layout mechanism to fix the layout of its members. It will invoke tab->layout_dialog: size to force all member tab objects to adjust themselves to the requested size.

If size is @default, the system will invoke tab->layout_dialog to all its members and then compute the union of the member tab objects to determine the required size. Next it will call this method again with the computed size.
tab_stack->on_top: member:tab Put indicated tab on top of the others. Normally this is called from the tab->event method after the user clicks on the label. of a hidden tab object.

Note that the argument may be the name of the tab rather than the tab itself.