# README

## 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 without compromising the declarative programming features of Prolog.

Logtalk is implemented as a trans-compiler 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, portable libraries, portable developer tools, and a large number of programming examples to help get you started.

## Logtalk web site

The latest release of the Logtalk is always available at the URL:

> https://logtalk.org/

At this address you can also find additional documentation and information about Logtalk.

## Installation

Logtalk can be installed either from sources by running a few shell scripts or by using one of the provided installers, depending on your operating system. For manual installation, see the file `INSTALL.md` for detailed instructions.

See the user manual for a description of the source files organization and for using instructions (to read the user manual open the file `manuals/index.html` with a web browser).

If you are upgrading from a previous Logtalk version, please check the `UPGRADING.md` file for instructions on how to upgrade your programs or your custom adapter files to run under this new version.

## Customization

The file `CUSTOMIZE.md` provides detailed instructions for customizing the Logtalk installation and working environment.

## Running

The file `QUICK_START.md` provides quick instructions for those of you in a hurry to run Logtalk, provided that your favorite Prolog compiler is supported.

## Documentation

A quick and highly recommended introduction for users comfortable with Prolog and with general knowledge about object-oriented programming is available at Learn X in Y minutes website.

The reference and user manuals are provided in XHTML and PDF formats and can be found in the `manuals` directory. They are also available online on the Logtalk website.

The `RELEASE_NOTES.md` file contains descriptions of all Logtalk updates since the first public version. Check it carefully if you have been using a previous Logtalk version.

The API documentation for the core, library, tools, and contributions entities is provided in XHTML format and can be found in the `docs` directory and also available online on the Logtalk website.

Most directories include `NOTES.md` or `NOTES.txt` documentation files.

On POSIX systems, there's also a man page for most shell scripts. A list of these scripts can be generated using the `apropos logtalk` command. HTML versions of the man pages are also available at the Logtalk website.

## Registration

To register as a Logtalk user either use the registration form found at the Logtalk web site, https://logtalk.org/regform.html, or send an email message to:

> registration@logtalk.org

with the following information:

email address, full name, organization, organization type (education, commercial, government, ...), prolog compilers used (optional), platforms (mac, pc, unix,...) (optional)

## Support

Support channels include:

- Professional services
- Community discussion forums
- Community live chat room

Please consult https://logtalk.org/support.html for more information.

## Citations

If you want to cite Logtalk in your publications, please consult the file `BIBLIOGRAPHY.bib` for bibliographic references in BibTeX format.

## Contributions

Contributions are most welcome! See the `CONTRIBUTING.md` file for details.

## Legal

Logtalk is copyrighted by Paulo Moura. The Logtalk use and distribution license can be found in the `LICENSE.txt`. Logtalk is available under the Apache License 2.0. The copyright notice and license applies to all files in this release unless otherwise explicitly stated. See the `NOTICE.txt` for detailed 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 of the included examples are adaptations to Logtalk of Prolog examples found elsewhere (e.g. in manuals, tutorials, books, and public mailing list discussions). The copyright in the examples original code should be assumed to belong to the original authors.

Logtalk is a registered trademark of Paulo Moura.