stk/STklos/%README

			STklos version 2.1
			------------------


What is STklos?
---------------

STklos is an extension of STk which provides a` la CLOS objets to STk. 
This implementation takes its inspiration from the version 1.3 of the
Tiny-clos package defined by Gregor Kickzales 
(available at parcftp.xerox.com:/pub/mop/*).

Compiling STklos
----------------
STklos is compiled during the interpreter construction. Normally, You don't
have to do something in this directory. 

Simple test of STklos
---------------------

STklos needs some files to run properly. Until you have installed it in its
definitive place, you have to:
	1. set your default directory to STklos
	2. use the the shell script test-stklos to run the interpreter 

So, you just have to type 

	$ cd STklos; test-stklos

To test, that everything is OK, you can try:
	(let ()
	  (define-class A () ((a :initform 10) b))
	  (define inst (make A))
	  (slot-set! inst 'b 20)
	  (+ (slot-ref inst 'a) (slot-ref inst 'b)))

which should yield 30 if everything is correct.

Using STklos with TK
--------------------

A set of classes have been defined to use Tk with object flavor. All the Tk
commands have been re-written using STklos. 

Following example creates a three buttons panel (button 1 & 2 being on top of
button 3).

   (require "Frame")
   (require "Button")
   (define f  (make <Frame>))
   (define b1 (make <Button> :text "Button 1" :parent f))
   (define b2 (make <Button> :text "Button 2" :parent f))
   (define b3 (make <Button> :text "Button 3"))
   (pack b1 b2 :side "left")
   (pack f b3 :fill "both" :expand #t)

Note usage of Scheme names in the two preceding pack calls instead of dotted
Tcl/Tk names.

Tk options can be seen as slot in the STklos world. So getting the font of 
button 3 can be done with 

   (font b3)

and changing its value can be done with 

   (set! (font b3) "fixed")

and associating a callback to button 1 can be done with the following expression

   (set! (command b1) '(format #t "You have typed on \"Button1\"\n"))

The desribe function permits to see all the slots value of a given object. For
instance, 

   (describe b2)

would give something like:

     #[<button> 122e44] is an instance of class <button>
     Slots are: 
	  id = #[Tk-command .v1.v3]
	  eid = #[Tk-command .v1.v3]
	  parent = #[<frame> f09d8]
	  bitmap = ""
	  width = 0
	  height = 0
	  anchor = "center"
	  font = "-Adobe-Helvetica-Bold-R-Normal--*-120-*"
	  foreground = "Black"
	  pad-x = 1
	  pad-y = 1
	  text = "Button 2"
	  text-variable = ""
	  background = "#cccccc"
	  border-width = 2
	  cursor = ""
	  relief = "raised"
	  active-background = "#999999"
	  active-foreground = "Black"
	  command = ""
	  disabled-foreground = "#b0b0b0"
	  state = "normal"


Destruction of a button can be obtained with the destroy-widget generic function
as in

    (destroy b2)

Examples
--------

Some examples are available in the Examples directory. What those
examples do is not interesting but rather how they are written.  Note:
There are not enough examples. Send me programs if you have intersting
pieces of code to make this directory growing.
Thanks



Have fun