This is cleaner than I thought it would be.

amazed how clean this is

... which can be a SolidDefinition or GraphDefinition

[2] What is the right thing to call these methods that can return a SolidDefinition or a GraphDefinition ? I don't think ISolidDefinition is as fitting in graph world as it was in composite solid world.

I don't expect this diff in particular to solve it, but it would be good to have a plan since I think its a pretty confusing intermediate state to be in so I want to make sure we move through it swiftly

@alangenfeld good call on moving do_composition 👍🏻

regarding ^ previous comment

throwing out some ideas for what to do with ISolidDefinition:

• AbstractSolidDefinition, get_abstract_solid()
• GraphNodeDefinition, get_node()
• NodeDefinition, get_node()

I'm not sure if we should rename that right now. In my mind a Graph *is* a solid. You can treat it as one, essentially. So it makes actually makes sense from a certain point of view. In that frame of mind the Playground it actually a thing that loads solid and you can execute them. Introducing another name might obfuscate things

I'm not sure if we should rename that right now

Yea I am not advocating for a rename in this diff necessarily, but I do want to try to reach some shared understanding of ontology. To me, this diff leaves the code base in a less readable / intuitive state, which is fine temporarily but not for very long.

The heart of the issue is that we have 3 things and currently only 2 names:

• SolidDefinition - a unit of user defined computation
• GraphDefinition - a graph of solids
• ??? - the abstract unit representing either

In my mind a Graph *is* a solid. You can treat it as one, essentially. So it makes actually makes sense from a certain point of view. In that frame of mind the Playground it actually a thing that loads solid and you can execute them. Introducing another name might obfuscate things

I think with this framing - you then need to have a name for the leaf / compute solid for when you need to be able to distinguish it. For example, how would you explain the execution plan creation process in this framing? I think with a reasonable name for the @solid solid ie ComputeSolid and then renaming methods that only deal in those ie get_compute_solids you get to an OK spot, but i do worry its still a bit confusing.

To me, thinking about trying to explain this to some one new - I really keep wanting a distinct third noun to distinguish from the others instead of relying on an adjective - which is why I suggested Node above.