FindPython: Add capability to specify Python implementations

Through hint Python_FIND_IMPLEMENTATIONS it is possble to specify, as an
ordered list, which implementations must be searched for.
Currently possible values are:
* CPython
* IronPython

1 files changed, 21 insertions, 0 deletions

diff --git a/Modules/FindPython.cmake b/Modules/FindPython.cmake
index 95c4a0f..93f77a8 100644
--- a/Modules/FindPython.cmake
+++ b/Modules/FindPython.cmake
@@ -271,6 +271,27 @@ Hints
     recommended to also include the component ``Interpreter`` to get expected
     result.
 
+``Python_FIND_IMPLEMENTATIONS``
+  This variable defines, in an ordered list, the different implementations
+  which will be searched. The ``Python_FIND_IMPLEMENTATIONS`` variable can
+  hold the following values:
+
+  * ``CPython``: this is the standard implementation. Various products, like
+    ``Anaconda`` or ``ActivePython``, rely on this implementation.
+  * ``IronPython``: This implementation use the ``CSharp`` language for
+    ``.NET Framework`` on top of the `Dynamic Language Runtime` (``DLR``).
+    See `IronPython <http://ironpython.net>`_.
+
+  The default value is the list: ``CPython``, ``IronPython``.
+
+  .. note::
+
+    This hint has the lowest priority of all hints, so even if, for example,
+    you specify ``IronPython`` first and ``CPython`` in second, a python
+    product based on ``CPython`` can be selected because, for example with
+    ``Python_FIND_STRATEGY=LOCATION``, each location will be search first for
+    ``IronPython`` and second for ``CPython``.
+
 Artifacts Specification
 ^^^^^^^^^^^^^^^^^^^^^^^