________________________________________________________________________

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.
________________________________________________________________________


`lgtdoc`
========

This is the default Logtalk documenting tool for generating API documentation
for libraries and applications. It uses the structural reflection API to
extract and output in XML format relevant documentation about a source file,
a library or directory of source files, or all loaded source files. The tool
predicates accept several options for generating the XML files, including
the output directory.

The `lgtdoc/xml` directory contains several ready-to-use Bash and PowerShell
scripts for converting the XML documenting files into final formats, including
(X)HTML, PDF, Markdown, and reStructuredText (for use with Sphinx), and plain
text files. The scripts are described in their `man` pages and made available
in the system path by default.


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

This tool requirements for converting the XML files it generates to a final
format are as follows:

1. Converting XML files to (X)HTML, reStructuredText, Markdown, or plain text
files requires a XSLT processor. The supported XSLT processors for Bash
conversion scripts are:

* xsltproc: https://gitlab.gnome.org/GNOME/libxslt/-/wikis/home
* Xalan: https://xml.apache.org/xalan-c/index.html
* Saxon: https://www.saxonica.com

On Windows, the PowerShell scripts use the .Net XSLT classes.

The reStructuredText files output is usually used as an intermediate step
to generate Sphinx HTML, PDF, ePub, and Texinfo files. The additional
requirements are:

* Sphinx: https://www.sphinx-doc.org/  
* Pygments: https://pygments.org/
* Read the Docs theme: https://github.com/readthedocs/sphinx_rtd_theme

2. Converting XML files to PDF files require a XSL-FO processor. The supported
XSL-FO processors for Bash and PowerShell conversion scripts are:

* Apache FOP processor: https://xmlgraphics.apache.org/fop/
* RenderX XEP processor: https://www.renderx.com/

For additional details, including compatible dependency versions and available
conversion scripts, see the `xml/NOTES.md` file. See the `tools/NOTES.md` file
for per operating-system installation instructions for the above dependencies.


API documentation
-----------------

This tool API documentation is available at:

[../../apis/library_index.html#lgtdoc](../../apis/library_index.html#lgtdoc)


Loading
-------

This tool can be loaded using the query:

	| ?- logtalk_load(lgtdoc(loader)).


Testing
-------

To test this tool, load the `tester.lgt` file:

	| ?- logtalk_load(lgtdoc(tester)).


Documenting source code
-----------------------

For information on documenting your source code, notably on documenting
directives, consult the documenting section of the User Manual:

[../../handbook/userman/documenting.html](../../handbook/userman/documenting.html)

Extracting documenting information from your source code using this tool
requires compiling the source files using the `source_data(on)` compiler
flag. For example:

	| ?- logtalk_load(source_file, [source_data(on)]).

Usually, this flag is set for all application source files in the corresponding
loader file. In alternative, you may also turn on the `source_data` flag
globally by typing:

	| ?- set_logtalk_flag(source_data, on).

The tool API allows generating documentation for libraries, directories, and
files, complemented with library, directory, entity, and predicate indexes.
Note that the source files to be documented **must** be loaded prior to using
this tool predicates to generate the documentation.


Generating documentation
------------------------

For a simple application, assuming a library alias is defined for it (e.g.
`my_app`), and at the top-level interpreter, we can generate the application
documentation by typing:

	| ?- {my_app(loader)}.
	...

	| ?- {lgtdoc(loader)}.
	...

	| ?- lgtdoc::library(my_app).
	...

By default, the documenting XML files are created in a `xml_docs` directory in
the current working directory. But usually all documenting files are collected
for both the application and the libraries it uses in a common directory so
that all documentation links resolved properly. The `lgtdoc` predicates can
take a list of options to customize the generated XML documenting files. See
the remarks section in the [lgtdocp](../../docs/apis/library_index.html#lgtdoc)
protocol documentation for details on the available options.

After generating the XML documenting files, these can be easily converted into
final formats using the provided scripts. For example, assuming that we want
to generate HTML documentation:

	$ cd xml_docs
	$ lgt2html -t "My app"

To generate the documentation in Sphinx format instead (as used by Logtalk
itself for its APIs):

	$ cd xml_docs
	$ lgt2rst -s -- -q -p "Application name" -a "Author name" -v "Version X.YZ.P"
	$ make html

In this case, the generated documentation will be in the `xml_docs/_build/html/`
directory. See the scripts man pages or call them using the `-h` option to learn
more about their supported options.

For more complex applications, you can use the `doclet` tool to define a *doclet*
to automate all the steps required to generate documentation. The *doclet* message
that triggers the process can also be sent automatically when the `make` tool is
used with the `documentation` target.


Documentation linter checks
---------------------------

When the `lgtdoc_missing_directives` flag is set to `warning` (its usual default
value), the `lgtdoc` tool prints warnings on missing entity `info/1` directives
and missing predicate `info/2` and `mode/2` directives.

When the `lgtdoc_missing_info_key` flag is set to `warning` (its usual default
value), the `lgtdoc` tool prints warnings on entity `info/1` directive and
predicate `info/2` directive missing de facto required keys (e.g., `comment`,
`parameters` or `parnames` for parametric entities, `arguments` or `argnames`
for predicates/non-terminals with arguments).

When the `lgtdoc_invalid_dates` flag is set to `warning` (its usual default
value), the `lgtdoc` tool prints warnings on invalid dates (including dates
in the future) in `info/1` directives.

When the `lgtdoc_non_standard_exceptions` flag is set to `warning` (its usual
default value), the `lgtdoc` tool prints warnings on non-standard exceptions.
This linter check is particularly effective in detecting typos when specifying
standard exceptions.

When the `lgtdoc_missing_punctuation` flag is set to `warning` (its usual
default value), the `lgtdoc` tool prints warnings on missing ending periods
(full stops), exclamation marks, or question marks in `info/1-2` directives
(in comments, remarks, parameter descriptions, and argument descriptions).

Set a flag value to `silent` to turn off the corresponding linter warnings.
