add default_python replacement to sphinx
and get docs version from the package so it doesn't get out of date
@@ -80,9 +80,19 @@ author = 'Project Jupyter'
# built documents.
#
# The short X.Y version.
-version = '0.1'
+import repo2docker
+version = repo2docker.__version__
# The full version, including alpha/beta/rc tags.
-release = '0.1'
+release = version
+
+from repo2docker.buildpacks.conda import CondaBuildPack
+
+default_python = CondaBuildPack.major_pythons['3']
+
+rst_prolog = """
+.. |default_python| replace:: **Python {default_python}**
+.. |default_python_version| replace:: {default_python}
+""".format(default_python=default_python)
# The language for content autogenerated by Sphinx. Refer to documentation
# for a list of supported languages.
