add information about the version cli

Author: gidden

source/arche/cli.rst

@@ -0,0 +1,53 @@
+.. _cli:
+
+Archetype Command Line Interface
+=======================================
+
+Many of the archetype-specific |Cyclus| CLI commands are automatically generated
+if the Cyclus preprocessor is used. For example, member variables added with
+``#pragma cyclus var`` are added to the generated input XML schema, e.g., 
+
+  .. code-block:: bash
+
+      $ cyclus --agent-schema :agents:Source
+      <interleave>
+	  <element name="commod">
+	      <data type="token"/>
+	  </element>
+	  <optional>
+	      <element name="recipe_name">
+		  <data type="token"/>
+	      </element>
+	  </optional>
+	  <element name="capacity">
+	      <data type="double"/>
+	  </element>
+      </interleave>
+
+However, other CLI interactions exist if they are implemented on the archetype.
+
+Archetype Versioning
+--------------------
+
+The ``cyclus::Agent`` class exposes a ``version()`` member function which is
+queried by the |Cyclus| CLI. For example, 
+
+  .. code-block:: bash
+
+      $ cyclus --agent-version :agents:Source
+      1.3.1-7-g9a2c9c9
+
+This is generated from some ``git`` version control information. You can make
+your own version tag information for some archetype like
+
+
+  .. code-block:: c++
+
+      virtual std::string version() { return "My Version"; }
+
+and then access the version with
+
+  .. code-block:: bash
+
+      $ cyclus --agent-version my_package:my_library:MyArchetype
+      My Version

source/arche/index.rst

@@ -83,6 +83,7 @@ Interfacing with the |Cyclus| Kernel
     custom_tables
     errors
     logger
+    cli
 
 A Word About Style
 ++++++++++++++++++