Overview
========

Spot is a model-checking toolkit comprising:
  - a C++17 library with data-structures and algorithms for working
    with linear-time temporal logical formulas and ω-automata with
    any acceptance condition.
  - a set of command-line tools for easy access to those algorithms,
    with convenient interfaces to third-party tools also manipulating
    similar concepts.
  - Python bindings (including Jupyter interfaces) for the library,
    making it easier to play with and discover those concepts.


Documentation
=============

Some documentation can be found in the doc/ directory.

- doc/userdoc/ is basically a local copy of the web-site at
  https://spot.lrde.epita.fr/.  It contains several explanations and
  illustrations of the core concepts and tools; it has installation
  instructions; and also provide several code examples.

- doc/spot.html/ contains documentation for the C++ library.  It is
  generated automatically from the source code using Doxygen.

- doc/tl/tl.pdf contains documentation about the various temporal
  logic operators supported by Spot.  It provides semantics, syntax,
  and gives an exhaustive list of all implemented rewritings.

"make install" will also install man pages for command-line tools.
(These man pages can also be found in the spot/bin/man/ subdirectory
of the source tree.)  Additional documentation about these tools can
also be found in doc/userdoc/.

An important part of the documentation that is missing is the
documentation of the Python bindings.  Currently all we have is a
collection of examples, which are all collected at
http://spot.lrde.epita.fr/tut.html (or doc/userdoc/tut.html in the
source tree).  This is hardly ideal, but we do not have the resources
to maintain such a manual for the Python binding by hand.  If you have
an idea about how to generate a manual for the Python bindings
automatically, please do contribute!


Keeping in touch
================

If you have questions regarding Spot, or bug to report, please send
them to <spot@lrde.epita.fr>.  This is a public mailing list which you
may subscribe to at https://www.lrde.epita.fr/mailman/listinfo/spot
but you should feel free to post without subscribing.

We also run a low-traffic and read-only list for announcements of new
releases of Spot.  You may subscribe to that list at
https://www.lrde.epita.fr/mailman/listinfo/spot-announce


History
=======

This project started in 2003 at LIP6 (www.lip6.fr).  The main author
moved to LRDE (www.lrde.epita.fr) in 2007, and all regular
contributors are now at LRDE.  The web site was moved from
spot.lip6.fr to spot.lrde.epita.fr in 2015, so do not be surprised if
you find links to the old site.


Installation
============

Requirements
------------

Spot requires a C++17-compliant compiler.  G++ 7.x or later, as well
as Clang++ 5.0 or later should work.

Spot expects a complete installation of Python (version 3.5 or later).
Especially, Python's headers files should be installed.  If you don't
have Python installed, and do NOT want to install it, you should run
configure with the --disable-python option (see below).


Optional third-party dependencies
----------------------------------

Several tools and functions output automata as "dot files", to be
rendered graphically by tools from the GraphViz package.  Installing
GraphViz is therefore highly recommended if you plan to display
automata.

If the SAT-solver glucose is found on your system, it will be used by
our test suite to test our SAT-based minimization algorithm.

Spot used to distribute a modified version of LBTT (an LTL to Büchi
test bench), mostly fixing errors reported by recent compilers.
However Spot now distributes its own reimplementation of LBTT, called
ltlcross, so the use of LBTT is completely optional.  The last
modified version of LBTT we used to distribute can now be found at
  http://www.lrde.epita.fr/dload/spot/lbtt-1.2.1a.tar.gz
If some lbtt binary is found on your system, it will be used in the
test suite in addition to ltlcross.


Building and installing
-----------------------

Spot follows the traditional `./configure && make && make check &&
make install' process.  People unfamiliar with the GNU Build System
should read the file INSTALL for generic instructions.

If you plan to use the Python binding, we recommend you use one
of the following --prefix options when calling configure:

  --prefix /usr
  --prefix /usr/local  (the default)
  --prefix ~/.local    (if you do not have root permissions)

The reason is that all these locations are usually automatically
searched by Python.  If you use a different prefix directory, you may
have to tune the PYTHONPATH environment variable.

In addition to its usual options, ./configure will accept some
flags specific to Spot:

  --disable-python
    Turn off the compilation of Python bindings.  These bindings
    offers a convenient interface when used in an IPython notebook,
    and are also used to build the CGI script that translates LTL
    formulas on-line.  You may safely disable these, especially if you
    do not have a working Python 3.2+ installation or if you are
    attempting some cross-compilation.

  --enable-max-accsets=N
    Compile Spot so that it supports up to N acceptance sets.  The
    default is 32, so that the membership of each transition to
    any of the 32 acceptance sets can be represented by an
    "unsigned int" (interpreted as a bit-vector).  Using a larger
    N (it still has to be a multiple of 32) will consume more
    unsigned ints per transitions, costing both time and space.

  --enable-doxygen
    Generate the Doxygen documentation for the code as part of the
    build.  This requires Doxygen to be installed.  Even if
    --enable-doxygen has not been given, you can force the
    documentation to be built by running "make doc" inside the doc/
    directory.

  --enable-devel
    Enable debugging symbols, turn off aggressive optimizations, and
    turn on assertions.  This option is effective by default in
    development versions (version numbers ending with a letter).
    It is equivalent to
      --enable-debug
      --enable-warnings
      --enable-assert
      --enable-optimizations=-O
  --disable-devel
    Disable development options.  This is the case by default in
    releases (version numbers NOT ending with a letter).
    It is equivalent to
      --disable-debug
      --disable-warnings
      --disable-assert
      --enable-optimizations

   --enable-glibgxx-debug
     Enable the debugging version libstdc++
     https://gcc.gnu.org/onlinedocs/libstdc++/manual/debug_mode_semantics.html
     Note that the debugging version of libstdc++ is incompatible with
     the regular version.  So if Spot is compiled with this option, all
     client code should be compiled with -D_GLIBCXX_DEBUG as well.  This
     options should normally only be useful to run Spot's test-suite.

   --enable-c++20
     Build everything in C++20 mode.  We use that in our build farm to
     ensure that Spot can be used in C++20 projects as well.

Here are the meaning of the fine-tuning options, in case
--enable/disable-devel is not enough.

  --disable-assert
  --enable-assert
    Control assertion checking.

  --disable-warnings
  --enable-warnings
    Whether warnings should be output.  Note that during development
    we consider warnings to be errors.

  --disable-debug
  --enable-debug
    Whether to compile extra debugging code.

  --enable-optimizations
  --enable-optimizations=FLAGS
  --disable-optimizations
    Whether the compilation should be optimized.  When FLAGS are
    given, use these as optimization flags.  Otherwise, pick working
    flags from a built-in list.


Troubleshooting installations
-----------------------------

Spot installs five types of files, in different locations.  It the
following, $prefix refers to the directory that was selected using
the --prefix option of configure (the default is /usr/local/).

1) command-line tools go into $prefix/bin/
2) shared or static libraries (depending on configure options)
   are installed into $prefix/lib/
3) Python bindings (if not disabled with --disable-python) typically
   go into a directory like $prefix/lib/pythonX.Y/site-packages/
   where X.Y is the version of Python found during configure.
4) man pages go into $prefix/man
5) header files go into $prefix/include

Depending on how you plan to use Spot, you may have to adjust some
variables such that all these files can be found by the other programs
that look for them.

To test if command-line tools are correctly installed, try running

  % ltl2tgba --version

If your shell reports that ltl2tgba is not found, add $prefix/bin
to you $PATH environment variable.

If the dynamic linker reports that some library (usually libspot.so or
libbddx.so) is not found, you probably have to instruct it to look into
some new directory.  If you installed Spot as root into a classical
system prefix such as /usr or /usr/local/ it may be the case that you
simply have to refresh the cache.  In GNU/Linux this is done by
running "ldconfig -v".  If you installed Spot into a non-standard
directory, you may have to add $prefix/lib some some environment
variable: that variable is called LD_LIBRARY_PATH in GNU/Linux, and
its DYLD_LIBRARY_PATH in Darwin.

To test the Python bindings, try running

  % python3
  >>> import spot
  >>> print(spot.version())

If you installed Spot with a prefix that is not one of those suggested
in the "Building and installing" section, it is likely that the above
import statement will fail to locate the spot package.  You can show
the list of directories that are searched by Python using:

  % python3
  >>> import sys
  >>> print(sys.path)

And you can modify that list of searched directories using the
PYTHONPATH environment variable.

To test if man pages can be found, simply try:

  % man spot

If man reports a message like "No manual entry for spot", add
$prefix/man to the MANPATH environment variable.

Finally header files are needed if you write some C++ that uses Spot.
In that case you may need to pass some -I option to the compiler to
add some "include" directory.  At link time, you may also need to add
some -L option if the libraries are not in some location that is
already searched by the linker.  The file doc/userdoc/compile.html (or
its on-line version at https://spot.lrde.epita.fr/compile.html)
discusses this topic a bit more.


Layout of the source tree
=========================

Core directories
----------------

spot/             Sources for libspot.
   graph/         Graph representations.
   ltsmin/        Interface with DiVinE2 and SpinS.  (Not part of libspot.)
   kripke/        Kripke Structure interface.
   tl/            Temporal Logic formulas and algorithms.
   misc/          Miscellaneous support files.
   mc/            All algorithms useful for model checking
   parseaut/      Parser for automata in multiple formats.
   parsetl/       Parser for LTL/PSL formulas.
   priv/          Private algorithms, used internally but not exported.
   ta/            TA objects and cousins (TGTA).
   taalgos/       Algorithms on TA/TGTA.
   twa/           TωA objects and cousins (Transition-based ω-Automata).
   twacube/       TωA objects based on cube (not-bdd).
   twacube_algos/ TωAcube algorithms
   twaalgos/      Algorithms on TωA.
      gtec/       Couvreur's Emptiness-Check (old version).
   gen/           Sources for libspotgen.
bin/              Command-line tools built on top of libspot.
   man/           Man pages for the above tools.
tests/            Test suite.
   core/          Tests for libspot and the binaries.
   ltsmin/	  Tests for the DiVinE2/SpinS interface.
   python/        Tests for Python bindings.
   sanity/        Tests for the coherence of the source base.
doc/              Documentation for Spot.
   org/           Source of userdoc/ as org-mode files.
   tl/            Documentation of the Temporal Logic operators.
   userdoc/       HTML documentation about command-line tools, and examples.
   spot.html/     HTML doc for C++ API (not distributed, use --enable-doxygen).
bench/            Benchmarks for ...
   dtgbasat/      ... SAT-based minimization of DTGBA,
   emptchk/       ... emptiness-check algorithms,
   ltl2tgba/      ... LTL-to-Büchi translation algorithms,
   ltlcounter/    ... translation of a class of LTL formulas,
   ltlclasses/    ... translation of more classes of LTL formulas,
   spin13/        ... compositional suspension and other improvements,
   stutter/       ... stutter-invariance checking algorithms,
   wdba/          ... WDBA minimization (for obligation properties).
python/           Python bindings for Spot and BuDDy

Third party software
--------------------

buddy/            A customized version of BuDDy 2.3 (a BDD library).
ltdl/             Libtool's portable dlopen() wrapper library.
lib/              Gnulib's portability modules.
utf8/             Nemanja Trifunovic's utf-8 routines.
elisp/		  Related emacs modes, used for building the documentation.
picosat/          A distribution of PicoSAT 965 (a satsolver library).
spot/bricks/      A collection of useful C++ code provided by DiVinE

Build-system stuff
------------------

m4/      M4 macros used by configure.ac.
tools/   Helper scripts used during the build.
debian/  Configuration file to build Debian packages.

-------------------------------------------------------------------------------
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