This is the distribution directory for HOL4. See http://hol-theorem-prover.org for online resources.

See the HOL homepage for more detailed installation instructions, including for Windows.

HOL4 supports multiple SML compilers:

• Poly/ML (recommended) — The primary backend for building and running HOL4.
• Moscow ML (version 2.10) — An alternative backend, ensuring HOL sources remain portable across SML implementations.
• MLton (optional) — If installed, automatically used to build tool executables (Holmake, etc.) which may run faster.

For Poly/ML, ensure that your dynamic library loading can find libpolyml.so and libpolymain.so. If these are not in /usr/lib, you may need to set LD_LIBRARY_PATH, e.g.:

export LD_LIBRARY_PATH=/usr/local/lib:$HOME/lib

In the HOL directory, run:

poly --script tools/smart-configure.sml

(or mosml < ... for Moscow ML). Then:

bin/build

If smart-configure guesses options incorrectly, create tools-poly/poly-includes.ML with corrected ML bindings (e.g., val holdir = "/path/to/hol").

Once the build completes, the key executables are:

bin/hol       The standard HOL interactive system
bin/Holmake   A batch compiler for HOL directories

Note that the system is built in place and cannot easily be moved after installation.

Some components include C/C++ code that requires a C compiler:

• src/HolSat/sat_solvers/minisat/ contains the MiniSat SAT solver sources. Run make in that directory to build.
• examples/muddy/ contains the BDD library, which requires building the shared library in examples/muddy/muddyC/.

If the build fails, try bin/build cleanAll before rebuilding. To report problems, come find us on Zulip, and/or use the GitHub issues page.

The following is a brief listing of what's available in the distribution.

 README.md      * This file
 CONTRIBUTORS   * List of contributors
 COPYRIGHT      * Copyright notice
 bin/           * Executables
 developers/    * Resources for developers
 doc/           * Release notes
 examples/      * Example formal developments, from small to large
 help/          * Sources for online help
 Manual/        * System manuals
 sigobj/        * Collection of all signatures and compiled code
 src/           * System sources
 std.prelude    * File loaded at the beginning of each HOL session
 tools/         * Support for building the system
 tools-poly/    * Poly/ML-specific support for building the system