Switch to lazy module imports

[pbontrager]

Use lazy imports for modules so that you only import the the classes you actually use. For each submodule like actors, controller, data, etc you define the public apis at the top and then define a getattr method to import them only when requested. This will make imports faster and avoid, avoid circular dependencies, and make optional dependencies easier to manage. At the app level, users would be expected to import

from forge.actor import Policy or from forge.data import collate_packed.

[joecummings]

Please give me until tomorrow to look at this

[ebsmothers]

This is an abomination lol. While I definitely appreciate the motivation, I worry that this is introducing a maintenance nightmare down the line

[ebsmothers]

Suggested change

	raise AttributeError("fmodule {__name__} has no attribute {name}")
	raise AttributeError(f"module {__name__} has no attribute {name}")

[pbontrager]

While I definitely appreciate the motivation, I worry that this is introducing a maintenance nightmare down the line

How is this harder to maintain than what we had before? It's just more verbose, not more complex. I can implement the getattr method to grab the imports from a dictionary so future updates are only one line, but you said it looked too complex.

[ebsmothers]

Oh if we're choosing between the two options I would prefer the other one. With this approach every new API added needs a corresponding else block in an __init__ file.. seems like a very obvious footgun for contributors.

While I definitely appreciate the motivation, I worry that this is introducing a maintenance nightmare down the line

How is this harder to maintain than what we had before? It's just more verbose, not more complex. I can implement the getattr method to grab the imports from a dictionary so future updates are only one line, but you said it looked too complex.

[joecummings]

See #83