________________________________________________________________________

This file is part of Logtalk <https://logtalk.org/>  
SPDX-FileCopyrightText: 1998-2025 Paulo Moura <pmoura@logtalk.org>  
SPDX-License-Identifier: Apache-2.0

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
________________________________________________________________________


README
======

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About
-----

Logtalk is a *declarative object-oriented logic programming language* that
extends and leverages the Prolog language with a feature set suitable for
programming in the large. Logtalk supports modern code encapsulation and
code reuse mechanisms while preserving the declarative programming features
of Prolog.

Logtalk is implemented as a transcompiler in highly portable code and can
use most modern and standards-compliant Prolog implementations as a backend
compiler.

As a multi-paradigm language, Logtalk includes support for both *prototypes*
and *classes*, *protocols* (*interfaces*), *categories* (components and
hot-patching), *event-driven programming*, *coinduction*, *lambda expressions*,
and *high-level multi-threading programming*. Logtalk uses standard Prolog
syntax with the addition of some operators and directives for a smooth learning
path.

Logtalk is distributed under a commercial-friendly license and includes full
documentation, tutorials, portable libraries, a comprehensive set of portable
developer tools, and numerous programming examples to help get you started.

Logtalk development adheres to the Contributor Covenant
[code of conduct](CODE_OF_CONDUCT.md). By participating,
you are expected to uphold this code. Please report
unacceptable behavior to contact@logtalk.org.


Logtalk website
---------------

The latest stable release of Logtalk is always available at:

https://logtalk.org/

At this address you can download installers for your operating-system and
find full documentation on Logtalk.


Installation
------------

Logtalk can be installed either from sources by running a couple of shell
scripts or by using an [installer](https://logtalk.org/download.html) for your
operating system. For manual installation, see the [INSTALL.md](INSTALL.md)
file for detailed instructions.

The [RELEASE_NOTES.md](RELEASE_NOTES.md) file contains descriptions of all
Logtalk updates since the first public version. Please check it if you are
upgrading from a previous Logtalk version.

If you are upgrading from the previous Logtalk 2.x generation, please check
the [UPGRADING.md](UPGRADING.md) file for instructions on how to upgrade your
programs or your custom adapter files to run under Logtalk 3.x.


Customization
-------------

The [CUSTOMIZE.md](CUSTOMIZE.md) file provides detailed instructions for
customizing the Logtalk installation and working environment.


Running
-------

The [QUICK_START.md](QUICK_START.md) file provides quick instructions for
those of you in a hurry to run Logtalk, provided that your favorite Prolog
compiler is supported and installed.


Documentation
-------------

A quick and highly recommended introduction for users comfortable with Prolog
and with general knowledge about object-oriented programming is available at
the [Learn X in Y minutes](https://learnxinyminutes.com/docs/logtalk/) website.

The HTML version of the Logtalk Handbook is included with the sources and can
be found in the [manuals](manuals/) directory. It's also available online at:

https://logtalk.org/manuals/index.html

PDF, ePub, and Texinfo versions of the Logtalk Handbook can be downloaded from:

https://logtalk.org/documentation.html

The Handbook is the entry point for the Logtalk documentation. It includes the
user manual, the reference manual, glossary, FAQ, the library overviews, plus
the developer tools documentation.

The API documentation for the core, library, tools, and contributions is
provided in HTML format and can be found in the [docs](docs/) directory and
also available online at:

https://logtalk.org/docs/index.html

Most directories include `NOTES.md` documentation files.

On POSIX systems, there's also a [man page](man/man1) for most shell scripts.
A list of these scripts can be generated using the `apropos logtalk` command.
[HTML versions](https://logtalk.org/documentation.html#man-pages) of the man
pages are also available at the Logtalk website.


Registration
------------

To register as a Logtalk user, please use the registration form at:

https://logtalk.org/regform.html

Registration is optional. But it's also a way of showing your support and
an opportunity for us to learn about the cool projects where you will be
using Logtalk.


Support
-------

Support channels include:

* [Community discussion forum](https://github.com/LogtalkDotOrg/logtalk3/discussions)
* [Community live chat room](https://app.gitter.im/#/room/#LogtalkDotOrg_logtalk3:gitter.im)
* [Support contracts](https://logtalk.org/support_contracts.html)

For more information on support options, please consult:

https://logtalk.org/support.html


Citations
---------

If you find Logtalk useful, please include a citation in your publications
(also cite the used backend Prolog compilers). The [BIBLIOGRAPHY.bib](BIBLIOGRAPHY.bib)
file includes bibliographic references in BibTeX format (including the 2003
PhD thesis on Logtalk design and implementation and the Logtalk Handbook).
See also the [CITATION.cff](CITATION.cff) file.


Contributions
-------------

Contributions are most welcome! See the [CONTRIBUTING.md](CONTRIBUTING.md) file
for details.


Legal
-----

Logtalk is copyrighted by Paulo Moura and made available under the Apache
License 2.0. See the [LICENSE.txt](LICENSE.txt) file for the license terms.
The copyright notice and license apply to all files in this release unless
otherwise explicitly stated. See the [NOTICE.txt](NOTICE.txt) for additional
copyright information.

Some files that are part of the Logtalk distribution are distributed using
a different license and/or are copyrighted by a Logtalk contributor.

Some examples are adaptations to Logtalk of Prolog examples found elsewhere
(e.g., in manuals, tutorials, books, and public discussion forums). See those
examples documentation for information on the sources of the original code.

Logtalk is a registered trademark of Paulo Moura.
