A Roadmap to Entity Relationships

[HexDecimal]

I've been using Sander Mertens articles to implement relationships. I've implemented these in the basic sense but they also have an article that describes a roadmap for a more complete implementation.

• [x] Components as entities - Python objects natively support what this is trying to do
• [ ] #6
• [ ] Support relationship pairs in archetype storage
• [x] Relationship components - Already added
• [ ] Wildcard queries - Half of this is implemented
• [x] The component index
• [ ] Cleanup
• [ ] Cleanup traits
• [ ] Multi-source queries
• [x] Relationship traversal
• [x] Query cache revalidation
• [x] Breadth first traversal
• [ ] Uncached queries
• [ ] Multi component observers
• [ ] Event propagation
• [ ] Empty table optimization
• [ ] Garbage collection
• [ ] Rule engine
• [x] Exclusive relationships - Already added as an alternative syntax for relationship access
• [x] #12
• [x] Query DSL - Probably not needed for a Python library

I don't know if I'll ever complete this. Some of these might be too slow when implemented in pure-Python and if I were to make a C extension then I may as well just port Flecs itself to Python.

It's clear that these features will be incredibly useful once added. At the very least I should keep all of these in mind as I work on this module.