Message system unclear and buggy

[jwaa]

Currently MATRX uses a bit of a mix of two message systems. The old one where messaging was handled in a very closed-off way. Users had to provide the content (a simple dict), and pass it to MATRX who wraps it in a Message instance and does all the rest. The new system allows more customization, most importantly the creation of your own message classes that inherit from Message. This changed the "just provide content" mandate to "provide a Message instance". However, this switch was not complete.

There are quite some unclarities in the code, inline comments and documentation. Also, something just work strangely with potential unintended side effects.

This resulted in the following list, which will be updated as we discover more things;

• This line still implies that messages are just content, not actual Message instances (as the check a few lines above it does imply.
• All received messages are deleted in agents (see this line)
• Unclear now how to actually make and send a message from an AgentBrain
• Unclear how to properly receive and read a received message in an AgentBrain
• Messages to groups of agents and teams was never sufficiently tested.
• Agents can only access the content of a received message (see Received messages only contain the content #230)
• Messages an agent send to all agents are also received by that agent but never cleared (see received messages remain in queue #240)
• Agents cannot access their past send messages (for instance this prevents the logging of send messages, see Logging send messages does not work nicely with step() #254)

[thaije]

Also see the related issue #201