Open-source implementation of the Action Language for fUML (Alf) specification.
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Action Language for UML (Alf)
Open Source Reference Implementation

Copyright © 2011-2017 Data Access Technologies, Inc. (Model Driven Solutions)

Alf is an action language for UML developed in response to the OMG Concrete Syntax for a UML Action Language Request for Proposals. The Alf specification document can be found at (See also for the list of issues addressed by the Alf 1.1 Revision Task Force.)

This implementation is based on the Alf 1.1 specification. It compiles Alf source text to the executable Foundational UML (fUML) subset of UML. The compilation can target either of two fUML execution engine implementations:

The implementation handles the full Alf syntax at the Extended compliance level, as given in Annex C Consolidated LL Grammar of the Alf Specification.

Static semantic checking is directly based on validating the constraints defined in the abstract syntax of the Alf Specification. However, as errors were discovered in these definitions, or inconsistencies with corresponding feature descriptions were identified, these were corrected in the implementation. All such issues have either been corrected in the latest version of the specification or have been reported to the Alf Revision Task Force for correction in a future version.

The latest version of the implementation is available at


Data Access Technology, Inc. is copyright owner of the source code for this implementation. For licensing terms, see the file LICENSING.txt.


The latest packaged distribution of the implementation is available in the dist directory.

Within this directory, the file unzips into the installation directory for Alf. The installation directory includes Unix (BASH) shell scripts and DOS batch files for running Alf. By default, the Libraries subdirectory is expected to be in the same directory as the scripts. If you move it, set the environment variable ALF_LIB to its path.


The implementation source is organized into four Eclipse projects. Eclipse 4.6 or later is required.

  • org.modeldriven.alf - This is the base project, including the Alf parser, static semantic checking and generic mapping to fUML. The generic mapping is not dependent on any specific UML metamodel or fUML implementation, but it must be extended with a specific UML metamodel implementation in order to generate actual UML model output.

  • org.modeldriven.alf.fuml.impl - This project extends the base project to specialize the mapping to target the fUML Reference Implementation and to allow compiled Alf text to be executed. It does not depend on the fUML Reference Implementation project directly but, rather, uses an exported fuml.jar file.

  • org.modeldriven.alf.eclipse - This project extends the base project to specialize the mapping to target the Eclipse UML2 metamodel implementation (v5.2.0 or later). It depends on Eclipse plugins and must be built in an Eclipse environment.

  • org.modeldriven.alf.eclipse.moka - This project extends the org.modeldriven.alf.eclipse project to allow compiled Alf text to be executed using the fUML execution engine from the Moka framework for model execution in the Eclipse Papyrus modeling tool (v3.1.0 or later). It depends on Eclipse plugins and must be built in an Eclipse environment. (Note: This project was called org.modeldriven.alf.eclipse.papyrus in previous versions of the reference implementation.)

Further Information

For further information on using the implementation, see the wiki.