Object Oriented GUI Programming

To program a GUI using an OO aproach, you need the stklos-gtklos package. This package implemenet a model close to the one described iin the JFP and ISOTAS papers.

To install the package, just issue the following command:

$ stklos-pkg --install stklos-gtklos
The package stklos-gtklos searches the system GUI toolkit libraries in some standard places (mainly /usr/lib and /usr/local/lib). If your libraries are installed in another directory, you can set the shell variable STKLOS_GTK_DIR to that directory name. This variable is used both for installing the ScmPkg and for running your program.

Before using this package, you can test that everything works with the following command:

$ stklos-pkg --test stklos-gtklos

Various demo programs are available when running the stklos-gtklos package test.


Hereafter is an example of interface built with stklos-gtklos:

The code used to produce this screenshot is:

;;;; entry.stk

(require "stklos-gtklos")
(import stklos-gtklos stklos-gtk-base)

(define (main args)
  (let* ((window (make <window> :title "STklos Entry and Events" :border-width 15))
         (box    (make <vbox> :parent window :padding 5 :expand #t))

         (line1  (make <hbox> :parent box))
         (line2  (make <hbox> :parent box))
         (quit   (make <button> :parent box :text "Quit" :command (λ (_) (exit 0))))

         (lab1   (make <label> :parent line1 :text "Only digits: " :width 150))
         (entry1 (make <entry> :parent line1))

         (lab2   (make <label> :parent line2 :text "Convert to upper: " :width 150))
         (entry2 (make <entry> :parent line2)))

    ;; digits entry
    (event-connect entry1 "key-press-event"
                   (lambda (e) (not (char-numeric? (event-char e)))))
    ;; upper entry
    (event-connect entry2 "key-release-event"
                   (lambda (e)
                     (let* ((pos (cursor-position entry2))
                            (val (value entry2))
                            (up  (string-upper val)))
                       (unless (equal? val up)
                         (set! (value entry2) up)
                         (set! (cursor-position entry2) pos)))))


Download gtklos-entry.stk

Here window is the application container. It contains a vertically arranged box called box. This box contains three children:

Each entry has its own event handler:

You can run this program with the followwing command (provided you have installed the stklos-gtklos package:

$ stklos -f gtklos-entry.stk

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