diff -r 98a0fbda8739 -r 5532823e8c18 rust/hg-cpython/src/lib.rs
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/rust/hg-cpython/src/lib.rs	Mon Dec 03 06:52:17 2018 +0100
@@ -0,0 +1,40 @@
+// lib.rs
+//
+// Copyright 2018 Georges Racinet <gracinet@anybox.fr>
+//
+// This software may be used and distributed according to the terms of the
+// GNU General Public License version 2 or any later version.
+
+//! Python bindings of `hg-core` objects using the `cpython` crate.
+//! Once compiled, the resulting single shared library object can be placed in
+//! the `mercurial` package directly as `rustext.so` or `rustext.dll`.
+//! It holds several modules, so that from the point of view of Python,
+//! it behaves as the `cext` package.
+//!
+//! Example:
+//! ```
+//! >>> from mercurial.rustext import ancestor
+//! >>> ancestor.__doc__
+//! 'Generic DAG ancestor algorithms - Rust implementation'
+//! ```
+
+#[macro_use]
+extern crate cpython;
+extern crate hg;
+
+mod ancestors;
+mod exceptions;
+
+py_module_initializer!(rustext, initrustext, PyInit_rustext, |py, m| {
+    m.add(
+        py,
+        "__doc__",
+        "Mercurial core concepts - Rust implementation",
+    )?;
+
+    let dotted_name: String = m.get(py, "__name__")?.extract(py)?;
+    m.add(py, "__package__", "mercurial")?;
+    m.add(py, "ancestor", ancestors::init_module(py, &dotted_name)?)?;
+    m.add(py, "GraphError", py.get_type::<exceptions::GraphError>())?;
+    Ok(())
+});