POPUP(2) POPUP(2)
NAME
Popup: mkbutton, changebutton, event, add - popup list box
pseudo-widget
SYNOPSIS
include "popup.m";
popup := load Popup Popup->PATH;
init: fn();
mkbutton: fn(win: ref Tk->Toplevel, name: string,
items: array of string, n: int): chan of string;
changebutton: fn(win: ref Tk->Toplevel, name: string,
items: array of string, n: int);
event: fn(win: ref Tk->Toplevel, e: string,
items: array of string): int;
add: fn(items: array of string, s: string):
(array of string, int);
DESCRIPTION
Popup implements popup list boxes as Tk pseudo-widgets.
This interface is provisional and subject to change.
Init must be called once to initialise the module.
Mkbutton creates a new button name, in Tk toplevel win. It
returns a channel on which it delivers events (see event,
below). Once created, name can be packed like any other Tk
widget. When the button is pressed with button 1, a menu
pops up offering a choice from the given items. The value n
is the index in items of the button's initial value. The
current choice is always displayed in the button. If items
is nil or an empty array, the string `-----' is displayed
instead.
Having created a popup button, the application must receive
values on the channel returned by mkbutton and pass each
value it receives to event (as parameter e). (Typically the
application will receive on the channel in an alt statement
that watches other channels too.) Event returns the result
of a selection, or -1 if no selection was made. In either
case, the text of the button name will reflect the currently
active selection (the application can fetch it using
`cget -text'). The items parameter must match that given to
mkbutton (or most recently given to changebutton).
Changebutton changes the list of items in an existing popup
button name, and sets its initial selection to the item with
index n.
Add adds string s to the array items, if it is not already
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POPUP(2) POPUP(2)
there, and in either case returns the resulting new array
and the index of s therein. It is useful for calculating a
list of items dynamically.
SOURCE
/appl/lib/popup.b
SEE ALSO
tabs(2), tk(2)
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