Sunday, January 6, 2019

New paper "Clafer: Lightweight Modeling of Structure, Behaviour, and Variability"

by Michał Antkiewicz, Jan 6, 2019

Our new paper "Clafer: Lightweight Modeling of Structure, Behaviour, and Variability" has been published in the journal The Art, Science, and Engineering of Programming.


Embedded software is growing fast in size and complexity, leading to intimate mixture of complex architectures and complex control. Consequently, software specification requires modeling both structures and behaviour of systems. Unfortunately, existing languages do not integrate these aspects well, usually prioritizing one of them. It is common to develop a separate language for each of these facets

In this paper, we contribute Clafer: a small language that attempts to tackle this challenge. It combines rich structural modeling with state of the art behavioural formalisms. We are not aware of any other modeling language that seamlessly combines these facets common to system and software modeling.

We show how Clafer, in a single unified syntax and semantics, allows capturing feature models (variability), component models, discrete control models (automata) and variability encompassing all these aspects. The language is built on top of first order logic with quantifiers over basic entities (for modeling structures) combined with linear temporal logic (for modeling behaviour). On top of this semantic foundation we build a simple but expressive syntax, enriched with carefully selected syntactic expansions that cover hierarchical modeling, associations, automata, scenarios, and Dwyer’s property patterns.

We evaluate Clafer using a power window case study, and comparing it against other notations that substantially overlap with its scope (SysML, AADL, Temporal OCL and Live Sequence Charts), discussing benefits and perils of using a single notation for the purpose.

NOTE: Behavioral Clafer does not currently have reasoning capabilities. The compiler implements the syntax of the language and it can desugar the syntactic sugar and produce HTML rendering. For the instance generation and multi-objective optimization capabilities, it's best to use the static Clafer 0.4.5, which works best with all instance generators and web tools.

Tuesday, September 18, 2018

"Clafer: unifying class and feature modeling" available publicly on Springer's SharedIt

by Michał Antkiewicz, Sep 18, 2018

Our paper  "Clafer: unifying class and feature modeling" can now be accessed freely via Springer's SharedIt initiative using the following link:


Tuesday, May 8, 2018

Behavioral Model Set

by Michał Antkiewicz, May 08, 2018

Clafer Model Wiki contains a few example models showcasing behavioral Clafer.
  1. TrafficLight. A simple state machine model for traffic light transitions.
  2. PowerWindow. Our main case study from the behavioral Clafer paper.
  3. WebSocketProtocol.
  4. TLS Handshake.

Thursday, February 1, 2018

Clafer Compiler 0.5.0 Released

by Michał Antkiewicz, Jan 31, 2018

This release contains only the Clafer compiler 0.5.0, which now includes support for modeling behavior. The release does not include reasoning capability; for structural modeling and reasoning keep using the previous release 0.4.5.

Binary builds are available from Clafer Tools - Binary Distributions.

Clafer compiler, release pull request (0.5.0).
  • support for behavioral modeling,
  • ability to compile, desugar, and render to HTML behavioral models,
  • test suite of behavioral models,
  • experimental Alloy code generator,
  • compatibility with GHC 8.2.2.
The Clafer model wiki is currently running Clafer 0.5.0.

Friday, September 22, 2017

Best paper award for SoSyM 2017

by Michał Antkiewicz, Sep 22, 2017

Our paper "Synthesis and exploration of multi-level, multi-perspective architectures of automotive embedded systems" published in the Software and Systems Modeling journal has won one of the six best paper awards for year 2017.

Congratulations to our students Jordan Ross, Jimmy Liang, and Alexandr Murashkin!

The work presented in the paper was Jordan's master's thesis work based on previous master's thesis work by Alexandr. Jimmy made it all possible by contributing chocosolver, the scalable Clafer backend.

Monday, September 18, 2017

Clafer Tutorial at CBSOFT'17

by Michał Antkiewicz, Sep 18, 2017

Today, prof. Andrzej Wąsowski (IT University of Copenhagen) delivered a 3.5h tutorial entitled "Domain Modeling and Variability Modeling in Clafer" at CBSOFT'17, Fortaleza, Brazil.

The tutorial introduced the Clafer language and the participants used the online Clafer tools to write and analyze their models.


Variability Modeling is a key activity in implementing Software Product Lines and highly configurable systems. Clafer is a small language for domain modeling with excellent support for variability modeling.  In this tutorial, we will introduce the basics of variability modeling and the basics of the  Clafer language.  Most of the tutorial will be interactive. The participants will use online Clafer tools to create basic models and analyze them, including consistency checking of models, and finding optimal configurations. Time permitting, we will discuss extensions of Clafer beyond structural domain modeling.

Tuesday, March 21, 2017

Behavioral Clafer

by Michał Antkiewicz, Mar 21, 2017

Behavioral Clafer was finally merged into develop, which means it will be part of the next release: 0.5.0.

That is a huge step for Clafer because it adds capability of modeling how the structures evolve over time. In that context, all possible instances of a static Clafer model can be considered as all possible snapshots (statespace) of a dynamic model. Also, the constraints in a static model can be considered as global invariants in a dynamic model.

The Clafer Model Wiki and the Clafer Tools (Visualizer, Configurator, and IDE) have been updated to use the 0.5.0 version; however, there is currently no reasoning support for the behavioral constructs. The models can only be compiled, desugared, and rendered to HTML.

We added two example models to showcase the behavioural modeling style:
  • Simplified Web Socket Protocol - a simple model showcasing state modeling, trace specification, and the intended traces.
  • Power Window - a complex model showcasing modeling structure and behaviour with variability: feature modeling, component modeling, statemachine modeling, variability in behaviour using alphabet variability, inheritance, and strategy pattern, and (safety) properties.

Monday, March 13, 2017

Clafer, ClaferIG, ClaferWiki 0.4.5 Released

by Michał Antkiewicz, Mar 13, 2017

This is mainly a maintenance release.

Clafer compiler, release pull request (0.4.5).
  • compatibility with GHC 8.0.2,
  • fixed an issue with references to singleton clafers in Choco generator.
Alloy-based instance generator, release pull request (0.4.5).
  • compatibility with GHC 8.0.2,
  • compatibility with clafer-0.4.5.
Claferwiki, release pull request (0.4.5).
  • compatibility with GHC 8.0.2,
  • compatibility with clafer-0.4.5 and the latest gitit-
ClaferToolsST, release commit (0.4.5).
  • updated Package Control installation instructions for the latest SublimeText3.

All other tools work with 0.4.5.

Monday, September 19, 2016

Clafer Tools 0.4.4 Released

by Michał Antkiewicz, Sep 19, 2016

This is a simultaneous release of all Clafer Tools.

Binary builds are available from Clafer Tools - Binary Distributions.

Clafer compiler, release pull request (0.4.4).
  • compatibility with GHC 8.0.1,
  • added support for nested abstract clafers to Choco generator,
  • fixed building with latest Alex and Happy,
  • fixed an issue with setting references with a union, #49,
  • add the synthetic "root", #57,
  • added partial support for `parent` of top-level abstract clafers (the model now compiles but the generators must be fixed), #84.
Alloy-based instance generator, release pull request (0.4.4).
  • compatibility with GHC 8.0.1.
Choco-based instance generator and multi-objective optimizer, release pull request (0.4.4).
  • a massive update of 249 commits and 460 files changed!
  • ported to the latest Choco version 4.0,
  • added support for reference refinement, 
  • improved support for nested abstract clafers: issues #23, #29, #30, #31.
  • many performance improvements,
  • implemented constructive disjunction optimization.
      Claferwiki, release pull request (0.4.4).
      • compatibility with GHC 8.0.1,
      • compatibility with clafer-0.4.4 and the latest gitit-
      ClaferToolsUICommonPlatform, release pull request (0.4.4).
      • fixed FQ matrix (fixed sorting, fixed references)
      • fixed Clafer API
      ClaferMOOVisualizer, release pull request (0.4.4).
      • minor fixes
      ClaferConfigurator, release diff (0.4.4).

      ClaferIDE, release diff (0.4.4).

      ClaferToolsST, release diff (0.4.4).
      • updated version numbers and links.
      ClaferMPS, release pull request (0.4.4).
      • added ability to extend the reference model with arbitrary clafers and constraints
      • added ability to add constraints to quality attributes
      • fixed quality table