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From: mayer@hplabsz.HPL.HP.COM (Niels Mayer)
Newsgroups: comp.windows.x
Subject: Re: Toolkit decisions (was: XView v. other toolkits, advice
Message-ID: <4882@hplabsz.HPL.HP.COM>
Date: 27 Feb 90 21:47:46 GMT
References: <9002261946.AA00365@snowking.Eng.Sun.COM>
Reply-To: mayer@hplabs.hp.com (Niels Mayer)
Organization: Hewlett-Packard Labs, Software Technology Lab, Palo Alto, CA.
Lines: 104
Summary:
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In article <9002261946.AA00365@snowking.Eng.Sun.COM> tomj@eng.sun.COM (Tom Jacobs) writes:
>Mike, the concept of a toolkit being object-oriented is not strictly
>limited to Smalltalk-style environments.  XView is an object-oriented
>system with static subclassing.  This simply means that the heirarchy
>of classes need to be defined at compile time (the same is true of the X
>Intrinsics).

This is probably drifting off the original topic (what was it anyways?)...
Since we're talking about using OOP with Xt and/or Xview, I thougt I'd
throw this in:

WINTERP uses XLISP's OOP extension to allow the instantiable Motif widgets
to be subclassed "dynamically". XLISP's OOP extension is somewhat
smalltalk-like.  WINTERP uses the C-implemented Motif widgets but makes
them look like XLISP objects, which can be subclassed. You can also add
and/or override "methods" on widget classes (for example, adding a
:FIND-FILE method to the XM_TEXT_WIDGET_CLASS)...

Here's a trivially simple example of using a subclassed widget in WINTERP
in order to simplify the use of a "radio box" selection mechanism:

; -*-Lisp-*-
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;
; File:         radiobox2.lsp
; RCS:          $Header: radiobox2.lsp,v 1.1 89/11/25 04:00:36 mayer Exp $
; Description:  A better (?) way of creating a radio box, using subclassing of
;               togglebutton. Note that this version doesn't waste as much
;               memory as radiobox1.lsp because it defines a single
;               entry-callback on the rowcolumn widget instead of forcing each
;               toggle-button to have separate copies of very similar
;               callback-closures. Just load this file to see the example.
; Author:       Niels Mayer, HPLabs
; Created:      Sat Nov 25 01:24:00 1989
; Modified:     Sat Nov 25 01:26:42 1989 (Niels Mayer) mayer@hplnpm
; Language:     Lisp
; Package:      N/A
; Status:       X11r4 contrib tape release
;
; (c) Copyright 1989, Hewlett-Packard Company.
;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

(setq toplevel_w
      (send TOP_LEVEL_SHELL_WIDGET_CLASS :new 
	    :XMN_GEOMETRY "500x500+1+1"
	    :XMN_TITLE "Radio-Box-Test #2"
	    :XMN_ICON_NAME "Radio-Box-Test #2"
	    ))

(setq rowcol_w
      (send XM_ROW_COLUMN_WIDGET_CLASS :new :managed :radio_box "rc" toplevel_w
	    ))

(send toplevel_w :realize)

(send rowcol_w :set_callback :xmn_entry_callback
       '(CALLBACK_ENTRY_WIDGET
	 CALLBACK_ENTRY_SET)
       '(
	 (if CALLBACK_ENTRY_SET
	     (send CALLBACK_ENTRY_WIDGET :print-which-button)
	   )
	 ))

;; make a subclass of XM_TOGGLE_BUTTON_GADGET_CLASS
(setq My_Toggle_Button			
      (send Class :new
	    '(button_name)		;a new ivar for this subclass
	    '()				;no class variables for subclass
	    XM_TOGGLE_BUTTON_GADGET_CLASS)) 

;; override XM_TOGGLE_BUTTON_GADGET_CLASS's instance initializer
(send My_Toggle_Button :answer :isnew '(name &rest args)
      '(
	(setq button_name name)
	(apply 'send-super `(:isnew ,@args
				    :xmn_label_string ,name))
	))

;; add a method that prints which button
(send My_Toggle_Button :answer :print-which-button '()
      '(
	(format T "option ~A selected\n" button_name)
	))

;; put up 20 toggle buttons inside the radio-box/row-column manager
(do* 
 (;; local vars
  (i 0 (1+ i))
  )
 (;; test and return
  (eql i 20)
  )
 ;; body
 (send My_Toggle_Button :new (format nil "Button ~A" i) :managed rowcol_w)
 )

-------------------------------------------------------------------------------
	    Niels Mayer -- hplabs!mayer -- mayer@hplabs.hp.com
		  Human-Computer Interaction Department
		       Hewlett-Packard Laboratories
			      Palo Alto, CA.
				   *