Robot Chef version 2: Use lml to write a shared library

Demo

Please checkout the following examples:

$ virtualenv --no-site-packages robotchefv2
$ source robotchefv2/bin/activate
$ git clone https://github.com/python-lml/robotchef_v2
$ cd robotchef_v2
$ python setup.py install
$ cd ..
$ git clone https://github.com/python-lml/robotchef_api
$ cd robotchef_api
$ python setup.py install

And then you can type in and test the second version of Robot Chef:

$ robotchef_v2 "Portable Battery"
I can cook Portable Battery for robots
$ robotchef_v2 "Jacket Potato"
I do not know how to cook Jacket Potato

In order to add "Jacket Potato" in the know-how, you would need to install robotchef_britishcuisine in this folder:

$ git clone https://github.com/python-lml/robotchef_britishcuisine_v2
$ cd robotchef_britishcuisine_v2
$ python setup.py install
$ robotchef_v2 "Jacket Potato"
I can bake Jacket Potato

Robot Chef v2 code

Let us look at main code robotchef_v2:

.. literalinclude:: ../../examples/v2/robotchef_v2/robotchef_v2/main.py
  :diff: ../../examples/robotchef/robotchef/main.py

The code highlighted in red are removed from main.py and are placed into robotchef_api package. And robotchef_v2 becomes the consumer of the robotchef api.

And plugin.py and robot_cuisine has been moved to robotchef_api package.

Robot Chef API

Now let us look at robotchef_api. In the following directory listing, the plugin.py And robot_cuisine is exactly the same as the :ref:`plugin.py <plugin>` and :ref:`robot_cuisine <builtin_plugin>` in robotchef:

__init__.py    plugin.py       robot_cuisine

Notably, the plugin loader is put in the __init__.py:

.. literalinclude:: ../../examples/v2/robotchef_api/robotchef_api/__init__.py
  :language: python

scan_plugins_regex here loads all modules that start with "robotchef_" and as well as the module robotchef_api.robot_cuisine in the white_list.

This is how you will write the main component as a library.

Built-in plugin and Standalone plugin

You may have noticed that a copy of robotchef_britishcuisine is placed in v2 directory. Why not using the same one above v2 directory? although they are almost identical, there is a minor difference. robotchef_britishcuisine in v2 directory depends on robotchef_api but the other British cuisine package depends on robotchef. Hence, if you look at the fry.py in v2 directory, you will notice a slight difference:

.. literalinclude:: ../../examples/v2/robotchef_britishcuisine/robotchef_britishcuisine/fry.py
  :diff: ../../examples/robotchef_britishcuisine/robotchef_britishcuisine/fry.py