updated API reference

py-polars/docs/source/reference/plugins.rst

@@ -3,13 +3,45 @@ Plugins
 =======
 .. currentmodule:: polars
 
-Plugins allow for extending Polars' functionality. See the
-`user guide <https://docs.pola.rs/user-guide/plugins/>`_ for more information
-and resources.
+Polars allows you to extend its functionality with either Expression plugins or IO plugins.
+See the `user guide <https://docs.pola.rs/user-guide/plugins/>`_ for more information and resources.
 
-Available plugin utility functions are:
+Expression plugins
+------------------
 
-.. automodule:: polars.plugins
-    :members:
-    :autosummary:
-    :autosummary-no-titles:
+Expression plugins are the preferred way to create user defined functions. They allow you to compile
+a Rust function and register that as an expression into the Polars library. The Polars engine will
+dynamically link your function at runtime and your expression will run almost as fast as native
+expressions. Note that this works without any interference of Python and thus no GIL contention.
+
+See the `expression plugins section of the user guide <https://docs.pola.rs/user-guide/plugins/expr_plugins/>`_
+for more information.
+
+.. autosummary::
+    :toctree: api/
+
+    plugins.register_plugin_function
+
+
+IO plugins
+------------------
+
+IO plugins allow you to register different file formats as sources to the Polars engines.
+
+See the `IO plugins section of the user guide <https://docs.pola.rs/user-guide/plugins/io_plugins/>`_
+for more information.
+
+.. note::
+
+    The ``io.plugins`` module is not imported by default in order to optimise import speed of
+    the primary ``polars`` module. Either import ``polars.io.plugins`` and *then* use that
+    namespace, or import ``register_io_source`` from the full module path, e.g.:
+
+    .. code-block:: python
+
+        from polars.io.plugins import register_io_source
+
+.. autosummary::
+    :toctree: api/
+
+    io.plugins.register_io_source