# Building the manual with Sphinx

This page explains how to build a local copy of the Pandemonium manual using the
Sphinx docs engine. This allows you to have local HTML files and build the
documentation as a PDF, EPUB, or LaTeX file, for example.

To get started, you need to:

1. Clone the `pandemonium-docs repository ( https://github.com/Relintai/pandemonium_engine-docs/ )`.
2. Install `Sphinx ( https://www.sphinx-doc.org/ )`
3. To build the docs as HTML files, install the `readthedocs.org theme
   ( https://github.com/snide/sphinx_rtd_theme )`.
4. Install the Sphinx extensions defined in the `pandemonium-docs repository
   ( https://github.com/Relintai/pandemonium_engine-docs/ )` `requirements.txt` file.

We recommend using `pip ( https://pip.pypa.io )`, Python’s package manager to
install all these tools. It comes pre-installed with `Python
( https://www.python.org/ )`. Ensure that you install and use Python 3. Here are
the commands to clone the repository and then install all requirements.

Note:
 You may need to write `python3 -m pip` (Unix) or  `py -m pip` (Windows) instead of `pip3`.
          If both approaches fail, `check that you have pip3 installed ( https://pip.pypa.io/en/stable/installation/ )`.

```
git clone https://github.com/Relintai/pandemonium_engine-docs.git
pip3 install -r requirements.txt
```

With the programs installed, you can build the HTML documentation from the root
folder of this repository with the following command:

```
# On Linux and macOS
make html

# On Windows, you need to execute the `make.bat` file instead.
make.bat html
```

If you run into errors, you may try the following command:

```
make SPHINXBUILD=~/.local/bin/sphinx-build html
```

Building the documentation requires at least 8 GB of RAM to run without disk
swapping, which slows it down. If you have at least 16 GB of RAM, you can speed
up compilation by running:

```
# On Linux/macOS
make html SPHINXOPTS=-j2

# On Windows
set SPHINXOPTS=-j2 && make html
```

The compilation will take some time as the `classes/` folder contains hundreds
of files.

You can then browse the documentation by opening `build/html/index.html` in
your web browser.

In case you of a `MemoryError` or `EOFError`, you can remove the
`classes/` folder and run `make` again. This will drop the class references
from the final HTML documentation but will keep the rest intact.

Note:
 If you delete the `classes/` folder, do not use `git add .` when
          working on a pull request or the whole `classes/` folder will be
          removed when you commit. See `#3157
          ( https://github.com/Relintai/pandemonium_engine-docs/issues/3157 )` for more
          detail.

Alternatively, you can build the documentation by running the sphinx-build
program manually:

.. code:: sh

   sphinx-build -b html ./ _build

You can also specify a list of files to build, which can greatly speed up compilation:

.. code:: sh

```
sphinx-build -b html ./ _build classes/class_node.rst classes/class_resource.rst
```

## Building with Sphinx and virtualenv

If you want your Sphinx installation scoped to the project, you can install
sphinx-build using virtualenv. To do so, run this command from this repository's
root folder:

.. code:: sh

```
virtualenv --system-site-packages env/
. env/bin/activate
pip3 install -r requirements.txt
```

Then, run `make html` as shown above.