________________________________________________________________________

This file is part of Logtalk <https://logtalk.org/>  
Copyright 1998-2021 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 applications and Logtalk itself. 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 scripts for converting
the XML documenting files into final formats including (X)HTML, PDF, Markdown,
and reStructuredText (for use with Sphinx), or plain text files. The scripts are
described in their `man` pages and made available in the system path by default.
See also the `lgtdoc/xml/NOTES.md` for details, including **required third-party
software**.


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

This tool API documentation is available at:

[../../docs/library_index.html#lgtdoc](../../docs/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:

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

Extracting documenting information from your source code using with 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 application directory. But usually all documenting files are collected
for both the application and the libraries it uses ar collected 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](https://logtalk.org/docs/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.
