Heptagon/BZR

Heptagon is a synchronous dataflow language whose syntax and semantics is inspired from Lustre, with a syntax allowing the expression of control structures (e.g., switch or mode automata).

Heptagon is also a research compiler, whose aim is to facilitate experimentation. The current version of the compiler includes the following features:

• Inclusion of discrete controller synthesis within the compilation: the language is equipped with a behavioral contract mechanisms, where assumptions can be described, as well as an "enforce" property part. The semantics of this latter is that the property should be enforced by controlling the behaviour of the node equipped with the contract. This property will be enforced by an automatically built controller, which will act on free controllable variables given by the programmer. This extension has been named BZR in previous works.

• Expression and compilation of array values with modular memory optimization. The language allows the expression and operations on arrays (access, modification, iterators). With the use of location annotations, the programmer can avoid unnecessary array copies.

  Heptagon is developed in the Parkas (ENS) and Ctrl-A (LIG/INRIA) research teams.

How to get it or try it

Installation with OPAM

The easiest and recommended way to install Heptagon/BZR is to use the OCaml Package Manager (OPAM).

The installation sequence using OPAM is :

1. Install OPAM (at least v2.0) : the procedure depends on your system and is described on the OPAM webpage.
2. (optional, for the graphical simulator) Install the gtk2.0 libraries (on debian systems, the package is named libgtk2.0-dev)
3. Initialize OPAM: opam init This command should install a version of OCaml at least ≥ 4.08. Follow the instructions given throughout this initialization.
4. Install Heptagon: opam install heptagon

To use the controller synthesis tool ReaX with Heptagon/BZR :

1. Install the mpfr and gmp libraries (on debian systems, packages named libmpfr-dev and libgmp-devel)
2. Add the repository for ReaX and its libraries (named here nberth-repo) :

     opam repo add nberth-repo "http://nberth.space/opam-repo"
     opam update
   

3. Install ReaX and its libraries, and the BZReaX script: opam install bzreax

The source code is also available from the Heptagon/BZR repository for manual compilation and installation. Further indications about ReaX can be found on the ReaX/ReaTk page.

Manual installation

Download

Heptagon can be freely downloaded here.

Technical requirements

The use of the Heptagon compiler by itself does not require any additional tools. However, the usual use involves a compiler for the generated code (target languages are currently C or Java).

To manually compile and install the Heptagon compiler, the following tools and libraries are needed:

• ocamlfind
• The menhir tool
• The ocamlgraph library
• camlp4
• The lablgtk library (optional, for the graphical simulator)
• The reatk library (optional, for the backend towards the ReaX controller synthesis too)

The tools below are optional or are related to some subparts of Heptagon:

• The graphical display tool sim2chro can be obtained from Verimag. It can be used together with Heptagon's graphical simulator.

Compilation and installation

Once the previously described libraries and tools are installed, the Heptagon compiler and libraries can be installed with:

    ./configure
    make
    make install