Hets is a parsing, static analysis and proof management tool incorporating various provers and different specification languages, thus providing a tool for heterogeneous specifications. Logic translations are first-class citizens.
The structuring constructs of the heterogeneous specification language are those of the language CASL, plus some constructs to select languages (logics) and language translations. The heterogeneous specification language of Hets is called HetCASL. However, Hets can also read other structuring constructs, like those of Haskell, Maude or OWL. All these are mapped to so-called development graphs and processed with a proof calculus for heterogeneous development graphs that allows to decompose global proof obligations into local ones (during this, Hets also needs to compute colimits of theories over the involved logics).
Hets is based on a graph of logics and logic translations. The overall architecture is depicted below. Adding new logics and logic translations to Hets can be done with moderate effort by adding some Haskell code to the Hets source. With the Latin project, this becomes much easier: logics (and in the near future also logic translations) can be declaratively specified in LF.
You can try out Hets using the Web-based interface
A compressed (1.2G, uncompressed 4.2G) virtual box image can be downloaded from here. username/password is ubuntu/reverse.
sudo apt-get install software-properties-common sudo apt-add-repository ppa:hets/hets sudo apt-get update sudo apt-get install hets-desktop
For Hets development additionally type in
sudo apt-add-repository -s "deb http://ppa.launchpad.net/hets/hets/ubuntu trusty main" sudo apt-get update sudo apt-get build-dep hets
Replace 'trusty' with the Ubuntu version that you use.
The Hets sources should be obtained from the git repository (see the end of this page).
These Disk images for the Hets application have only limited functionality. (GTK based menus are missing.)
(these are usually not needed but may replace the binaries from above)
Just download the binary and put it somewhere in the $PATH.
Download the CASL libraries and set $HETS_LIB to the folder containing these.
Hets is called with
hets -g filename
For entering the command line mode, just call
For a short description of the options, call
See RESTful Interface
A good starting point is the Hets user guide and the Hets user guide for Common Logic users. Furthermore two vidoes showing a heterogeneous proof are available:
For a formal introduction to hets see the introductory paper The Heterogeneous Tool Set by Till Mossakowski, Christian Maeder, Klaus Lüttich and Stefan Wölfl. For more in-depth information about Hets see the thesis Heterogeneous specification and the heterogeneous tool set by Till Mossakowski.
For questions related to hets there is a mailing list.
To support writing CASL specifications we have an emacs mode
With the option "-o pp.tex" hets can produce nice LaTeX output from your specifictions that can be embedded in your publications using the hetcasl.sty style file.
A good starting point is the code documentation for Hets - the Heterogeneous Tool Set.
Since Hets is rather large and complex we recommend following the interactive session in Debugging and Testing Hets to get familiar with the central datastructures of Hets.
The formal background and the general structure of Hets is described in chapter 7 of Heterogeneous specification and the heterogeneous tool set.
Hets is written in Haskell, and is compiled using GHC using a couple of language extensions. Among the Haskell books and tutorials we recommend Real World Haskell.
The language definition covers the Haskell98 standard which we are supposed to stick to in most cases. Make sure that you are familiar with at least the most common library functions of the Prelude.
For searching or looking up any library functions you may also try Hoogle.
Also look into programming guidelines and things to avoid in Haskell.
Dependencies can be installed as specified in Hets Development
Before committing haskell source files you may check compliance to the programming guidelines:
cabal install scan.
haddockto fail. After
make(for re-compiling changed sources)
make docwill call
cabal install hlint.
Also have a look at the current Release Notes, Debugging and Testing Hets,Code Review and Branching.
If you want to participate in the Hets development feel free to tell us via our mailing list for Hets developers. This mailing list can also be read via http://news.gmane.org/gmane.comp.lang.hets.devel.
If you wish to make larger changes we generally recommend forking this repository. You can however request access to this repository if you plan on contributing regularly.
The Hets source code is licensed under the GPLv2 or higher