Class

Summary

A collection collects together a set of items, and provides functionality for accessing and displaying them.

Superclasses

capi-object
callbacks

Subclasses

choice

Initargs

:items

The items in the collection.

:print-function

A function that prints an item.

:test-function

A comparison function between two items.

:items-count-function

A function which returns the length of items.

:items-get-function

A function that returns the n th item.

:items-map-function

A function that maps a function over the items.

:help-key

An object used for lookup of help.

Accessors

collection-items
collection-print-function
collection-test-function

Readers

collection-items-count-function
collection-items-get-function
collection-items-map-function
help-key

Description

The main use of collection is as a part of the class choice, which provides selection capabilities on top of the collection handling, and which is used by list panels, button panels and menus amongst others.

The items in the collection can either be arbitrary Common Lisp objects which can be printed with the print-function , or they can be instances of the CAPI class item in which case they are displayed with the text slot of the item. The main difference is that non-CAPI items use the callbacks specified for the collection, whilst the CAPI item s will use their callbacks in preference if these are specified.

By default, items must be a sequence, but this can be changed by specifying items-get-function , items-count-function , and items-map-function .

items-get-function should take as arguments the items and an index, and should return the indexed item. The default is svref .

items-count-function should take the items as an argument and should return the number of them.

items-map-function should take as arguments the items, a function function and a flag collect-results-p , and should call function on each of the items in return. If collect-results-p is non- nil , then it should also return the results of these calls in a list.

You can change the items using (setf collection-items) . Note that there is an optimization append-items that is sometimes useful when adding items.

help-key is intepreted as described in element.

Examples

The following code uses push-button-panel , a subclass of collection .

(capi:contain (make-instance 'capi:push-button-panel

                             :items '(one two three)))

(capi:contain (make-instance

               'capi:push-button-panel

               :items '(one two three)

               :print-function 'string-capitalize))

The following example provides a collection with all values from 1 to 6 by providing an items-get-function and an items-count-function .

(capi:contain (make-instance

               'capi:push-button-panel

               :items 6

               :items-get-function 

                 #'(lambda (items index) (1+ index))

               :items-count-function

                 #'(lambda (items) items)))

Here is an example demonstrating the use of CAPI items in a collections list of items to get more specific callbacks.

(defun specific-callback (data interface)

  (capi:display-message "Specific callback for ~S" 

                        data))

(defun generic-callback (data interface)

  (capi:display-message "Ordinary callback for ~S"

                        data))

(capi:contain (make-instance

               'capi:list-panel

               :items (list (make-instance

                             'capi:item

                             :text "Special"

                             :data 1000

                             :selection-callback 

                             'specific-callback)

                            2 3 4)

               :selection-callback 'generic-callback)

              :visible-min-width 200

              :visible-min-height 200)

See also

append-items
count-collection-items
get-collection-item
item
map-collection-items
search-for-item