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Member "jacl1.4.1/demos/pyramidpkg/README" (8 May 1999, 2404 Bytes) of archive /linux/misc/jacl1.4.1.tar.gz:

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README RCS: @(#) $Id: README,v 1.2 1999/05/08 23:27:10 dejong Exp $


  This demo shows how to embed a Tcl console in a Java applet.

Why Bother?

  By adding a Tcl console to the applet, we can dynamically
  change the functionality of applet's widgets.

Running The Demo

  The demo requires the appletviewer application. Therefore,
  the demo will not run under Tcl Blend. To run the demo you
  will need to do these 4 things.

  1) Run "make demos" in the build directory.

  2) Set your CLASSPATH to include the JDK's classes.zip file,
     the tcljava.jar file, the jacl.jar file, and .

  3) cd to demos/pyramidpkg (the directory containing this README)

  4) Then type "appletviewer pyramid.html" to begin the demo.

  The Java applet is comprised of three components: 
a) a drawing of a partially built pyramid.
b) buttons which allow the user to build and remove blocks from the
       drawing, and
c) a console which runs a Tcl interpreter.  The Tcl interpreter is
       extended with two new commands "build" and "remove" which allow
       the user to manipulate the pyramid in the same way as with the

  How do we change functionality of the applet's widgets dynamically?
  In the console, we can redefine the Tcl interpreter's "build" and
  "remove" commands.  If you look at the BuildButtonListener class in
  "Pyramid.java", you will see that the button is hardcoded to invoke
  the Pyramid's buildBlock() method.  We cannot change the behavior of
  this method from within Tcl.  However, if you look at the
  RemoveButtonListener class in "Pyramid.java", you will see that this
  button causes the "remove" command to be evaluated in the Tcl
  interpreter, thereby rendering its behavior dynamically changeable.
  Try typing the Tcl code in "changeDefs.tcl" into the applet console,
  and see the interesting results.  Although you are running an applet,
  the appletviewer tool allows you to source the file, so you can save
  yourself some typing (neither cutting nor pasting works in the
  console) by typing "source changeDefs.tcl".

Source Files

* Pyramid.java
* AppletConsole.java
* ConsoleKeyListener.java
* ConsoleMouseListener.java
* changeDefs.tcl