A DSL for VODML

This directory contains a proposal (still a work in progress) for a domain specific language serialization for the VODML called VODSL. The aims of the serialization are

• have something easier than XML to edit
• more constrained and specific than UML
• focused editors via eclipse Xtext with simultaneous graphical visualization via FXDiagram

Some background information and demonstration of how to use the editor can be found in this presentation.
and there is a screencast showing installation and simple use of the editor.

In addition to be able to use some of the features of the graphical visualization via FXDiagram it is worth looking at the introductory video on that site.

Prebuilt Plugins

The VODSL editor feature is available pre-built in an update site at http://astrogrid.jb.man.ac.uk/eclipse/vodsl/ if all you want to do is use the editor rather than develop it. In this case there is also a git submodule which contains some example models expressed in VODSL.

Using the stand-alone parser

It is possible to use the parser machinery in a stand-alone fashion (i.e. without having to work in eclipse) by using the jar file that is produced in the vodsl.standalone sub-directory.

The stand-alone parser is built using maven. All that is necessary after installing maven is to run (after building the editor plugin in the top level directory)

mvn install

in the vodsl.standalone/ directory and a jar file will be produced in target/ which can then be run with

java -jar vodslparser-0.4.0-SNAPSHOT.jar model.vodsl

which will produce a file model.vo-dml.xml of the equivalent VO-DML.

Developing VODSL

There are tutorials and reference documents to guide development on the Xtext site

The content of the various subdirectories is as follows;

1. net.ivoa.vodml - an eclipse project for the XText grammar for the DSL
2. net.ivoa.vodml.sdk - eclipse feature defintion the VODSL editor
3. net.ivoa.vodml.tests - tests for the VODSL
4. net.ivoa.vodml.ui - eclipse custom editor for the VODSL
5. vodsl.standalone - a stand-alone validating parser that will convert VODSL files to VO-DML
6. eclipse.target - a directory that defines the target eclipse installation
7. eclipse.repository - the installable VODSL editor feature update site will be created in this directory.

The essential steps to modifying this code and creating a plugin build

1. edit the grammar to add new features if desired
2. generate Xtext artifacts by right clicking on the grammar and selecting "generate Xtext Artifacts" from the "Run As" menu.
3. changing other behaviour of the plug-in in either the grammar or editor ui sub-projects.

All of the projects have now been converted to use maven tycho and so that all of the editors can be build by running the following in the top level directory.

mvn install

which will produce an installable feature update site in eclipse.repository/target/repository

Hints

• It is best to use the pre-configured "Eclipse modelling bundle" as your eclipse installation.
• to test in place with the minimally configured eclipse platform it is necessary to add "Eclipse UI IDE Application" to the list of automatically added plugin dependencies. and "Views Log"

Known issues with the Eclipse editor

• fully qualified names should have the model name followed by ':' and the rest of the packages delimited by '.' - This works for a full name, but the scoping sometimes allows a shorter name to be used - sometimes (when an auto-suggested model element is inserted) just the first part of the name (even when this is not a model name) is mistakenly delimited by ':'. In fact this does not matter internally as no distinction is made between the parts of the fully qualified name when it is split into its component parts. It does however make the VODSL slightly confusing to read in some cases.
• some of the VO-DML validation rules are not yet implemented
  • the "unique composition" rule, where an object type cannot be the target of two compositions.