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popup-confirmer Function


Creates a dialog with predefined implementations of OK and Cancel buttons and a programmer-specified pane in a layout with the buttons.




popup-confirmer pane message &rest interface-args &key title title-font value-function exit-function apply-function apply-check apply-button ok-function ok-check ok-button no-button no-function all-button all-function cancel-button help-button help-function buttons print-function callbacks callback-type button-position buttons-uniform-size-p foreground background font modal screen focus owner timeout x y position-relative-to button-container button-font continuation callback-error-handler => result, successp

A CAPI pane or interface.
A string or nil.
Initialization arguments for interface.
A string specifying the title of the dialog window.
The font used in the title.
Controls the value returned, and whether a value can be returned.
Called on exiting the dialog.
apply-function, apply-check, apply-button
Define the callback, check function and title an Apply button.
ok-function, ok-check, ok-button
Define the callback, check function and title of an OK button.
no-button, no-function
Define the title and callback of a No button.
all-button, all-function
Define the title and callback of an All button.
Defines the title of a Cancel button.
help-button, help-function
Define the title and callback of a Help button.
Defines extra buttons.
Displays ok-button, no-button, cancel-button, apply-button and all-button as button titles.
Defines callbacks for buttons.
Specifies the callback-type of buttons.
One of :bottom, :top, :left, :right.
Controls relative button sizes.
foreground, background
Specify colors.
A font or a font description.
modal, screen, focus, owner, timeout, x, y, position-relative-to
These are passed to display-dialog.
A layout controlling where the buttons of the dialog appear.
A font or a font description.
A function or nil.
A function designator or nil.
The result of value-function, or pane, or nil.
nil if the dialog was cancelled, t otherwise.

The function popup-confirmer is the quickest way to create new dialogs. It creates a dialog with predefined implementations of buttons such as OK and Cancel and a programmer-specified pane in a layout with the buttons.

Generally the Return key selects the dialog's OK button and the Escape key selects the Cancel button, if there is one.

The argument value-function should provide a callback which is passed pane and should return the value to return from popup-confirmer. If value-function is not supplied, then pane itself will be returned as result. If value-function wants to indicate that the dialog cannot return a value currently, then it should return a second value that is non-nil.

ok-check is passed the result returned by value-function and should return true if it is acceptable for that value to be returned. These two functions are used by popup-confirmer to decide when the OK button should be enabled, thus stopping the dialog from returning with invalid data. The OK button's state can be updated by a call to redisplay-interface on the top-level, so the dialog should call it when the button may enable or disable.

ok-button, no-button and cancel-button are the text strings for the OK, No and Cancel buttons respectively, or nil meaning do not include that button. The OK button returns successfully from the dialog (with the result of value-function), the No button means continue but return nil, and the Cancel button aborts the dialog. Note that there are clear expectations on the part of users as to the functions of these buttons — check the style guidelines of the platform you are developing for.

apply-button, if passed, specifies the title of an extra button which appears near to the OK button. apply-check and apply-function define its functionality.

all-button, if passed, specifies the title of an extra button which is always enabled and which appears near to the button added by apply-button (if that exists) or the OK button. all-function defines its functionality.

help-button, if passed, specifies the title of a help button which appears to the right of the Cancel button. help-function defines its functionality.

print-function is called on the various button arguments to generate a string to display for each button title.

button-position specifies where to put the buttons. The default is :bottom.

buttons-uniform-size-p specifies whether the buttons are all the same size, regardless of the text on them. The default is t, but nil can be passed to make each button only as wide as its text.

foreground and background specify colors to use for the parts of the dialog other than pane, including the buttons.

font specifies the font to use for message.

button-font specifies the font to use in the buttons.

button-container indicates where the buttons of the dialog appear. It must be a layout which is a descendant of pane. The description of this layout is automatically set to the button-panel containing the buttons.

exit-function, ok-function and no-function are the callbacks that are called when exiting, pressing OK and pressing No respectively. exit-function defaults to exit-confirmer, ok-function defaults to exit-function and no-function defaults to a function exiting the dialog with nil.

buttons, callbacks and callback-type are provided as a means of extending the available buttons. The buttons provided by buttons will be placed after the buttons generated by popup-confirmer, with the functions in callbacks being associated with them. Finally callback-type will be provided as the callback type for the buttons.

If any of callbacks need to access pane, you could use confirmer-pane together with a callback-type that passes the interface.

If continuation is non-nil, then it must be a function with a lambda list that accepts two arguments. continuation is called with the values that would normally be returned by popup-confirmer. On Cocoa, passing continuation causes the dialog to be made as a window-modal sheet and popup-confirmer returns immediately, leaving the dialog on the screen. The with-dialog-results macro provides a convenient way to create a continuation function.

callback-error-handler, if non-nil, should be a function designator for a function of one argument which is a condition, like the handler-function in cl:handler-bind. The handler is established (by cl:handler-bind with type cl:error) around each callback call inside the scope of popup-confirmer or display-dialog. In recursive calls, only the handler of the innermost call to popup-confirmer or display-dialog is established.

callback-error-handler can use current-popup to find the popup (first argument to the innermost call of display-dialog or popup-confirmer).

If callback-error-handler wants to do a non-local exit, it should either call abort-callback to abort the callback but leave the dialog, or exit-dialog (or abort-dialog) to exit (or abort) the dialog.

title, title-font, foreground,background, font and the initargs specified by interface-args will be passed to the call to make-instance for the interface that will be displayed using display-dialog. Thus geometry information, colors, and so on can be passed in here as well. foreground, background and font default to the corresponding values in pane.

modal, screen, focus, owner, timeout, x, y and position-relative-to will be passed to the call to display-dialog.

  1. On Microsoft Windows and Motif, the effect of callback-error-handler can be achieved by using cl:handler-bind around the call to display-dialog or popup-confirmer (the handler will also handle errors during raising the dialog, but these are not expected to happen). On Cocoa, using such an error handler does not necessarily work, because the callback may happen in another process. callback-error-handler ensures that the callback is in the scope of the handler on all platforms. From the same reason the handler should not rely on the dynamic environment (including catchers and restarts), and needs to use current-popup to find its "context" and use abort-callback, exit-dialog or abort-dialog for non-local exit.
  2. If the callback itself calls popup-confirmer or display-dialog, the error handler callback-error-handler will stay until the callback returns. Unless the recursive call handles the error, the handler of the outer call may be called to handle it, and needs to be written to deal with this possibility correctly. If the handler inside a recursive call needs to access the popup that was used in the same call that the handler was used, it should close over it, because current-popup returns the innermost one.
  3. A handler that is established by the callback (by cl:handler-bind or cl:handler-case) is inside the scope of callback-error-handler, and therefore will be called first.

Here are two simple examples which implement the basic functionality of two CAPI prompters: the first implements a simple prompt-for-string, while the second implements prompt-for-confirmation.

  (make-instance 'capi:text-input-pane
  "Enter some text:"
  :value-function 'capi:text-input-pane-text)
(capi:popup-confirmer nil 
  "Yes or no?"
  :callback-type :none
  :ok-button "Yes"
  :no-button "No"
  :cancel-button nil
  :value-function #'(lambda (dummy) t))

This example demonstrates the use of :redisplay-interface to make the OK button enable and disable on each keystroke.

(defun pane-integer (pane)
  (ignore-errors (values
  (make-instance 'capi:text-input-pane
                 :callback 'capi:exit-confirmer
                 :change-callback :redisplay-interface)
  "Enter an integer"
  :value-function 'pane-integer
  :ok-check 'integerp)

An example illustrating the use of :button-container:

(let* ((bt (make-instance 'capi:simple-layout 
                          :title "Button Container" 
                          :title-position :left))
       (tip1 (make-instance 'capi:text-input-pane 
                            :title "Top"))
       (tip2 (make-instance 'capi:text-input-pane 
                            :title "Bottom"))
       (layout (make-instance 'capi:column-layout 
                              (list tip1 
  (capi:popup-confirmer layout nil 
                        "Dialog using button-container" 
                        :button-container bt))

An example with all the defined buttons in use:

(defun all-buttons-dialog (&optional (num 20))
  (let ((pane 
         (make-instance 'capi:list-panel 
                        (loop for ii from 1 
                              to num 
                              (format nil "~r" ii))
                        '(character 20))))
     "All Buttons"
     :callback-type :none
     :button-position :right
     :cancel-button "Cancel Button"
     :ok-button "OK Button"
     :ok-function #'(lambda (x)
                      (declare (ignorable x))
                       (capi:choice-selected-item pane)))
     :no-button "No Button"
     #'(lambda ()
          (cons :no 
                (capi:choice-selected-item pane))))
     :apply-button "Apply Button"
     #'(lambda ()
          "Applying to ~a" 
          (capi:choice-selected-item pane)))
     :help-button "Help Button"
     #'(lambda ()
          "~a is ~:[an odd~;an even~] number"
          (capi:choice-selected-item pane)
          (oddp (capi:choice-selection pane))))
     :all-button "All Button"
          (capi:collection-items pane))))))

A dialog with arbitrary buttons:

 (make-instance 'capi:text-input-pane)
 "Dialog with arbitrary buttons"
 :buttons '(:abc :xyz)
 (list #'(lambda (data) 
            "Button ~A was pressed" data))
       #'(lambda (data)
            "Button with ~A was pressed, exiting with ~S" data data)
           (capi:exit-dialog data)))
 :callback-type :data)

This example illustrates the use of callback-error-handler:

(defun my-error-handler (condition)
  (let ((pane (capi:current-popup)))
     "Error inside dialog: ~a : ~a"
     (capi:capi-object-name pane)
      (lambda ()
        (let ((md (make-instance 
                   :text "Error inside Callback-Error-Handler"
                   :name "Chicken"
                   :callback-type :data
                   :data "Twisted ankle."
                   :callback 'error)))
           md nil
           :callback-error-handler 'my-error-handler))))
     (foo (make-instance
           "Popup confirmer with Callback-Error-Handler"
           :callback-type :none
           :callback foo-callback))
     (bar (make-instance
           :text "Error without a handler"
           :callback-type :data
           :data "Broken leg."
           :callback 'error)))
  (capi:contain (list foo bar)))
See also

10 Dialogs: Prompting for Input

CAPI User Guide and Reference Manual (Macintosh version) - 01 Dec 2021 19:31:27