stk/STklos/%README

                             STklos version 4.0



What is STklos

STklos is an extension of STk which provides <20> la CLOS objets to STk. This
implementation is based on the
implementation of version 1.3 of the Tiny CLOS  package defined by Gregor
Kickzales (available by ftp at parcftp.xerox.com:/pub/mop/*).

Compiling STklos

STklos is compiled during the interpreter construction. 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 ../Src/test-stk to run the interpreter

So, you just have to type

     $ cd STklos; ../Src/test-stk

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 the Tk toolkit

A set of classes have been defined to use Tk with object flavor. All the Tk
widgets have been  wrapped in STklos. classes.The following example creates
a three buttons panel (button 1 & 2 being on top of button 3).

     (require "Tk-classes")
     (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) (lambda ()
                           (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> 401bfdbc] is an instance of class <button>
     Slots are:
          id = #[Tk-command .v184.v214]
          eid = #[Tk-command .v184.v214]
          parent = #[<frame> 401b5304]
          bitmap = ""
          width = 0
          height = 0
          anchor = "center"
          font = "-Adobe-Helvetica-Bold-R-Normal--*-120-*-*-*-*-*-*"
          foreground = "Black"
          image = ""
          justify = "center"
          pad-x = 9
          pad-y = 3
          text = "Button 2"
          text-variable = ""
          underline = -1
          wrap-length = 0
          background = "#d9d9d9"
          border-width = 2
          cursor = ""
          highlight-background = "#d9d9d9"
          highlight-color = "Black"
          highlight-thickness = 0
          relief = "raised"
          take-focus = ""
          active-background = "#ececec"
          active-foreground = "Black"
          command = ""
          disabled-foreground = "#a3a3a3"
          state = "normal"

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

     (destroy b2)

Examples

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


Have fun.