ref: 02ac617541ca1a7bf82b1615fb5a58235469b5d3
dir: /man/2/popup/
.TH POPUP 2 .SH NAME Popup: mkbutton, changebutton, event, add \- popup list box pseudo-widget .SH SYNOPSIS .EX 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); .EE .SH DESCRIPTION .B Popup implements popup list boxes as Tk pseudo-widgets. This module has since been superseded by .IR choicebutton (2) in Tk itself, but remains for the moment for compatibility. .PP .B Init must be called once to initialise the module. .PP .B Mkbutton creates a new button .IR name , in Tk toplevel .IR win . It returns a channel on which it delivers events (see .BR event , below). Once created, .I 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 .IR items . The value .I n is the index in .I items of the button's initial value. The current choice is always displayed in the button. If .I items is nil or an empty array, the string .RB ` ----- ' is displayed instead. .PP Having created a popup button, the application must receive values on the channel returned by .B mkbutton and pass each value it receives to .BR event (as parameter .IR e ). (Typically the application will receive on the channel in an .B alt statement that watches other channels too.) .B Event returns the result of a selection, or -1 if no selection was made. In either case, the text of the button .I name will reflect the currently active selection (the application can fetch it using .RB ` cget\ -text '). The .I items parameter must match that given to .B mkbutton (or most recently given to .BR changebutton ). .PP .B Changebutton changes the list of .I items in an existing popup button .IR name , and sets its initial selection to the item with index .IR n . .PP .B Add adds string .I s to the array .IR items , if it is not already there, and in either case returns the resulting new array and the index of .I s therein. It is useful for calculating a list of items dynamically. .SH SOURCE .B /appl/lib/popup.b .SH SEE ALSO .IR tabs (2), .IR tk (2)