Add basic documentation site

.github/workflows/build_docs.yml

@@ -0,0 +1,42 @@
+name: Build Docs
+
+on:
+  push:
+    branches:
+      - main
+  workflow_dispatch:  # Make sure this job can be triggered manually
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      pages: write
+      id-token: write
+    steps:
+      - uses: actions/checkout@v5
+      - uses: actions/configure-pages@v3
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.13'
+      - name: Install dependencies
+        run: |
+          cd quaddtype/
+          python -m pip install --upgrade pip
+          python -m pip install "numpy @ git+https://github.com/numpy/numpy.git" pytest meson meson-python
+      - name: Build quaddtype package
+        run: |
+          cd quaddtype/
+          python -m pip install . -v --no-build-isolation
+      - name: Build Sphinx documentation
+        run: |
+          cd quaddtype/
+          python -m pip install ."[docs]"
+          make -C docs html
+      - name: Upload artifact
+        uses: actions/upload-pages-artifact@v3
+        with:
+          path: './quaddtype/docs/_build/html'
+      - name: Deploy to GitHub Pages
+        id: deployment
+        uses: actions/deploy-pages@v4

.gitignore

@@ -143,3 +143,6 @@ compile_commands.json
 /quaddtype/subprojects/sleef/
 /quaddtype/subprojects/pythoncapi-compat/
 .wraplock
+
+# docs
+/quaddtype/docs/_build/

quaddtype/README.md

@@ -25,7 +25,7 @@ np.array([1,2,3], dtype=QuadPrecDType("longdouble"))
 
 ## Installation from source
 
-#### Prerequisites
+### Prerequisites
 
 - **gcc/clang**
 - **CMake** (≥3.15)
@@ -170,4 +170,37 @@ This is a development feature to help detect threading issues. To build `numpy-q
   export CXXFLAGS="-fsanitize=thread -g -O0"
   export LDFLAGS="-fsanitize=thread"
   python -m pip install . -vv --no-build-isolation -Csetup-args=-Db_sanitize=thread
-  ```
+  ```
+
+## Building the documentation
+
+The documentation for the `numpy-quaddtype` package is built using Sphinx. To build the documentation, follow these steps:
+
+1. Install the required dependencies:
+
+   ```bash
+   pip install ."[docs]"
+   ```
+
+2. Navigate to the `docs` directory and build the documentation:
+
+   ```bash
+   cd docs/
+   make html
+   ```
+
+3. The generated HTML documentation can be found in the `_build/html` directory within the `docs` folder. Open the `index.html` file in a web browser to view the documentation, or use a local server to serve the files:
+
+   ```bash
+   python3 -m http.server --directory _build/html
+   ```
+
+### Serving the documentation
+
+The documentation is automatically built and served using GitHub Pages. Every time changes are pushed to the `main` branch, the documentation is rebuilt and deployed to the `gh-pages` branch of the repository. You can access the documentation at:
+
+```
+https://numpy.github.io/numpy-user-dtypes/
+```
+
+Check the `.github/workflows/build_docs.yml` file for details.

quaddtype/docs/Makefile

@@ -0,0 +1,20 @@
+# Minimal makefile for Sphinx documentation
+#
+
+# You can set these variables from the command line, and also
+# from the environment for the first two.
+SPHINXOPTS    ?=
+SPHINXBUILD   ?= sphinx-build
+SOURCEDIR     = .
+BUILDDIR      = _build
+
+# Put it first so that "make" without argument is like "make help".
+help:
+	@$(SPHINXBUILD) -M help "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)
+
+.PHONY: help Makefile
+
+# Catch-all target: route all unknown targets to Sphinx using the new
+# "make mode" option.  $(O) is meant as a shortcut for $(SPHINXOPTS).
+%: Makefile
+	@$(SPHINXBUILD) -M $@ "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)

quaddtype/docs/api_docs.rst

@@ -0,0 +1,7 @@
+NumPy QuadDType API Documentation
+=================================
+
+.. automodule:: numpy_quaddtype
+    :members:
+    :undoc-members:
+    :show-inheritance:

quaddtype/docs/conf.py

@@ -0,0 +1,29 @@
+# Configuration file for the Sphinx documentation builder.
+#
+# For the full list of built-in configuration values, see the documentation:
+# https://www.sphinx-doc.org/en/master/usage/configuration.html
+
+# -- Project information -----------------------------------------------------
+# https://www.sphinx-doc.org/en/master/usage/configuration.html#project-information
+
+project = 'NumPy QuadDType'
+copyright = '2025, NumPy Community'
+author = 'NumPy Community'
+
+# -- General configuration ---------------------------------------------------
+# https://www.sphinx-doc.org/en/master/usage/configuration.html#general-configuration
+
+extensions = [
+    'sphinx.ext.autodoc',
+    'sphinx.ext.napoleon',
+    'myst_parser',
+]
+
+templates_path = ['_templates']
+exclude_patterns = ['_build', 'Thumbs.db', '.DS_Store']
+
+# -- Options for HTML output -------------------------------------------------
+# https://www.sphinx-doc.org/en/master/usage/configuration.html#options-for-html-output
+
+html_theme = 'pydata_sphinx_theme'
+

quaddtype/docs/index.md

@@ -0,0 +1,8 @@
+```{include} ../README.md
+```
+
+```{toctree}
+:hidden:
+
+api_docs.rst
+```

quaddtype/docs/make.bat

@@ -0,0 +1,35 @@
+@ECHO OFF
+
+pushd %~dp0
+
+REM Command file for Sphinx documentation
+
+if "%SPHINXBUILD%" == "" (
+	set SPHINXBUILD=sphinx-build
+)
+set SOURCEDIR=.
+set BUILDDIR=_build
+
+%SPHINXBUILD% >NUL 2>NUL
+if errorlevel 9009 (
+	echo.
+	echo.The 'sphinx-build' command was not found. Make sure you have Sphinx
+	echo.installed, then set the SPHINXBUILD environment variable to point
+	echo.to the full path of the 'sphinx-build' executable. Alternatively you
+	echo.may add the Sphinx directory to PATH.
+	echo.
+	echo.If you don't have Sphinx installed, grab it from
+	echo.https://www.sphinx-doc.org/
+	exit /b 1
+)
+
+if "%1" == "" goto help
+
+%SPHINXBUILD% -M %1 %SOURCEDIR% %BUILDDIR% %SPHINXOPTS% %O%
+goto end
+
+:help
+%SPHINXBUILD% -M help %SOURCEDIR% %BUILDDIR% %SPHINXOPTS% %O%
+
+:end
+popd

quaddtype/pyproject.toml

@@ -37,6 +37,12 @@ test = [
     "pytest-run-parallel"
 ]
 
+docs = [
+    "sphinx",
+    "pydata-sphinx-theme",
+    "myst-parser",
+]
+
 [project.urls]
 Repository = "https://github.com/numpy/numpy-user-dtypes"
 Documentation = "https://github.com/numpy/numpy-user-dtypes/tree/main/quaddtype"