Using the JMPL Compiler

Compiler Version: 2.0

Andrew Bachmann

May 23, 2001

Introduction to the JMPL Compiler

The JMPL Compiler is used to convert JMPL into a format suitable for loading into the Livingstone Engine. For more information about JMPL, read the Introduction to JMPL. The compiler works in three steps. The first step is to load the files that contain the source objects that are to be instantiated. The second step is to fully instantiate a class. The compiler instantiates the specified top-level class, and its subcomponents, and their subcomponents, etc. As part of this instantiation, the compiler performs a logical transform on the constraints, reducing them to CNF form. The third step is writing the files out in XMPL format. XMPL is the XML-based Model-based Programming Language.

Using the JMPL Compiler through Stanley

When using Stanley, the JMPL Compiler is automatically invoked. Error messages from the compiler will be shown in a window.

Using the JMPL Compiler with JDK 1.2

The JMPL Compiler is available independent of Stanley in a Java Archive File. (JAR) The JMPL Compiler is available through the cvs repository for Code IC at NASA Ames Research Center. If you don't have access, please email someone on the project to request the compiler. An executable jar is available in the cvs subdirectory "skunkworks/java/jars" with the name "SkunkWorksFull-bin.jar". This jar includes all third-party libraries. A jar with sources is available with the name "SkunkWorksFull-src.jar".

The JmplCompiler can be found at:

gov.nasa.arc.skunkworks.io.jmpl.JmplCompiler

Run the compiler like this:

Supply a component type, component name, and at least one file name:

java gov.nasa.arc.skunkworks.io.jmpl.JmplCompiler <component type>

<component name> <filename1> <filename2> ...

Example:

java gov.nasa.arc.skunkworks.io.jmpl.JmplCompiler sensor sensor1

"c:\\directory\\filename.jmpl"

Both the component type and component name are mandatory. At least one

filename must be specified. The output of the compiler will be stored

in a file called <component name>.xmpl, which should be saved in the

current directory. (YMMV?)

By the way, since I am on windows, the example shows a windows pathname.

On unix, the slashes are the opposite direction, and, of course, there

is no such thing as "c:".

Compiler Messages

The compiler currently gives some basic feedback on what file it is currently loading, and how it is progressing in the compilation. The most helpful feedback is in the error messages.

Error Messages

The compiler or the parser may run into an error. If the parser runs into an error, you should see the error below the prompt showing the file loading. It will likely give a line number, and some basic explanation of what the error is. Usually this error will be of the form: "expecting xxx, found yyy". If the compiler runs into an error, you will hopefully see something a little more helpful. The compiler tries to convey as much context as possible. This section will be expanded in the future to show some sample error messages and explanations.

User Feedback

Especially since we are in the preliminary stages of the JMPL compiler, and the new Skunk Works debugging tools, user feedback is very important to us. Here are some categories of feedback that we are looking for in particular.

Bug Reports

This is a preliminary release. Although most everything you want works, certain things may not work exactly right. If you think something isn't working right, please check your code, then please send the following to Andrew Bachmann. (mailto:abachmann@mail.arc.nasa.gov)

1. your code - please attempt to reduce the size of the code to as small as will exhibit the problem

2. what it does - what happened when you tried to compile/use your code?

3. what you think it should do - what did you expect to happen?

Usage Comments

If you spent a half an hour figuring out how to do something, let us know. Especially if you have an idea on how it could work better or be more transparent. If you got back some error message and couldn't understand it, and eventually figured it out, send us an email about the message, and what you finally figured out.

Feature Requests

If you think that something is missing, don't hesitate to put it in as a feature request. Especially if you really need a particular feature. If it is something of particular urgence, please emphasize that fact, so we can prioritize it over things of less concern.

Usage Questions

If you are not sure about how to do something, ask us a question. Your question could become a new helpful section in this or another piece of documentation.