TM
© S. Sverdlov 1998

Oberon-2 compiler

Net (with source)
Filler (with source)
Voracity (with source)
Sea Battle

Download J( )B
J.Class Optimizer

Characteristics

Source language	Oberon-2
Target language	Java Virtual Machine (JVM) byte code (.class files)
J( )B compiler execution environment	Windows-95, Windows NT (console application)
Applications, compiled by J( )B, execution environment	Any, Java Virtual Machine supporting platform
Applets, compiled by J( )B, execution environment	Any Internet browser with Java support. Appletviewer from Java Development Kit (JDK)
Modules, compiled from Oberon-2, can be used with classes, compiled from Java. The class files of created by J( )B can be loaded by Java-tools: Borland JBuilder etc. Java Development Kit (JDK) can be loaded free from http://www.javasoft.com/products/jdk/
System requirements	Less than 1MB of memory for compilation; ~ 500K on disk
Libraries	Oakwood Guidelines compatible modules : In, Out, Files, Strings, Math, MathL, XYplane 46 definitions modules for Java API 1.02 (javalang, javaawt, javaapplet etc.)

J( )B installation

J( )B is distributed as a single self-extracting archive.

Create JOB directory.
Run self-extracting archive (in JOB directory):
C:\JOB\job_075.exe
Edit files job.bat, java.bat and av.bat. This files is written as if J( )B is located in C:\JOB, and JDK - in C:\JAVA. If you use other directories, change C:\ in this files.

Copy files job.bat, java.bat and av.bat to C:\WINDOWS directory.

Hello, World!

Let source code located in file hello.o:

MODULE Hello;

IMPORT javalang, Out;

PROCEDURE main*( VAR args : ARRAY OF javalang.PString ); 
BEGIN 
   Out.String("Hello, World!"); Out.Ln; 
END main;

END Hello.

Compilation:

C:\JOB\EXAMPLES\HELLO>job hello.o

JOB(tm) Oberon-2/JVM compiler. Strawberry version 0.75
(c) 1998 S.Sverdlov


Module      Hello
Code size   17

Press <ENTER>

Compiler created two files: Hello.class and Hello.dfn. Now, run program (Hello.class):

C:\JOB\EXAMPLES\HELLO>java Hello
Hello, World!

C:\JOB\EXAMPLES\HELLO>

Good!. For compilation and execution of our program we used files job.bat and java.bat.

Look at files Hello.dfn and Hello.class:

Hello.dfn is ASCII-file:

DEFINITION Hello;

IMPORT javalang;

PROCEDURE main( VAR args : ARRAY OF javalang.PString );

END Hello.

Class file is binary. It is disassembled:

Compiled from hello.o
public class Hello extends java.lang.Object {
    public static void main(java.lang.String []);
        /* Stack=1, Locals=1, Args_size=1 */
    public Hello();
        /* Stack=1, Locals=1, Args_size=1 */

Method void main(java.lang.String [])
   0 ldc #5 <String "Hello, World!\0">
   2 invokevirtual #8 <Method java.lang.String.toCharArray()[C>
   5 invokestatic #10 <Method Out.String([C)V>
   8 invokestatic #12 <Method Out.Ln()V>
  11 return

Method Hello()
   0 aload_0
   1 invokenonvirtual #15 <Method java.lang.Object.<init>()V>
   4 return

}

Black Square Applet

This is the first applet compiled by J( )B .

MODULE BlackSquare;

IMPORT app:=javaapplet, awt:=javaawt;

TYPE
   App* = RECORD (app.Applet) END;

PROCEDURE ( VAR a : App ) paint*( g : awt.PGraphics );
BEGIN
   g.fillRect(30,30,140,140);
END paint;

END BlackSquare.

Black Square is a famous picture of Kasimir Malevich.

Now, compilation:

C:\JOB\EXAMPLES\BSQUARE>job black.o

JOB(tm) Oberon-2/JVM compiler. Strawberry version 0.75
(c) 1998 S.Sverdlov


Module      BlackSquare
Code size   31

Press <ENTER>

For the running Black Square applet use the appletviewer program from JDK. As parameter for appletviewer it is possible to specify the source code file, if this file contains <APPLET> tag:

(* First JOB compiled applet!
   "Black Square"
   Designed (1913) by Kasimir Malevich
   Programmed (2.03.98) by S.Sverdlov

   <APPLET code="BlackSquare_App" width=200 height=200>
   </APPLET>
*)

MODULE BlackSquare;
........

Run appletviewer (av.bat batch file):

C:\JOB\EXAMPLES\BSQUARE>av black.o

After that on the screen there is such window:

S. Sverdlov
c3c@uni-vologda.ac.ru
July 1998