callbacks

callbacks Class

Summary

The class callbacks is used as a mixin by classes that provide callbacks.

Package

capi

Superclasses

capi-object

Subclasses

collection
item
menu-object

Initargs

`:callback-type`	The type of arguments for the callbacks.
`:selection-callback`
	The callback for selecting an item.
`:extend-callback`	The callback for extending the selection.
`:retract-callback`	The callback for deselecting an item.
`:action-callback`	The callback for an action.
`:alternative-action-callback`
	The callback for an alternative action in choice and its subclasses.

Accessors

callbacks-callback-type
callbacks-selection-callback
callbacks-extend-callback
callbacks-retract-callback
callbacks-action-callback

Description

Each callback function can be one of the following:

`function`	Call the function.
`list`	Apply the head of the list to the tail.
`:redisplay-interface`
	Call redisplay-interface on the top-level interface.
`:redisplay-menu-bar`
	Call redisplay-menu-bar on the top-level interface.

The slot value callback-type determines which arguments get passed to each of the callbacks. It can be any of the following values, and passes the corresponding data to the callback function:

`:collection-data`	`(collection data)`
`:data`	`(item-data)`
`:data-element`	`(item-data element)`
`:data-interface`	`(item-data interface)`
`:element`	`(element)`
`:element-data`	`(element item-data)`
`:element-item`	`(element item)`
`:interface-data`	`(interface item-data)`
`:item`	`(item)`
`:item-element`	`(item element)`
`:item-interface`	`(item interface)`
`:interface-item`	`(interface item)`
`:interface`	`(interface)`
`:full`	`(item-data item interface)`
`:focus`	The pane with the current input focus.
`:none`	`()`
`nil`	`()`

callback-type can also be a list containing any of :focus, :data, :element, :interface, :collection, :item.

The item-data variable is the item's data if the item is of type item, otherwise it is the item itself, as for item. The item variable means the item itself. The interface is the element-interface of the element. collection is the element's collection, if there is one. The element variable means the element containing the callback itself.

In a choice, the alternative-action-callback is invoked by a gesture which is the action-callback gesture modified by the Shift key on Microsoft Windows and GTK+, and modified by the Command key on Cocoa.

alternative-action-callback is applicable only to choice and its subclasses.

Apart from being invoked with a different gesture, the alternative-action-callback has exactly the same semantics as action-callback.

Examples

(example-edit-file "capi/choice/alternative-action-callback")