There's going to be more where this came from. Since this is our main
API, directly exposing all of the built-in functionality at this layer
is desirable.
Having thought about this more, it seems likely that complex converters
could benefit from being able to parse their arguments on the fly
without having to structure them into a rigid type. This is sort of a
get out of jail free card for custom converters as they can dump into
the user context type or whatever they want directly.
I believe we've produced a superset of the functionality that was
present before rewriting all of the code.
There are still a lot of fiddly little details that need to be thought
through in order to produce something that is righteously flexible,
but I think this is in reasonable shape to start inventing real-world
uses for it.
Adding some tests, cleaning up a little bit of the allocation handling
(make better use of the arena allocators—we are definitely sort of
leaking memory at the moment), and writing documentation are still on
the roadmap.
I am resisting the urge to try to codegolf this into fewer lines. It's
going to end up being a sprawl, but it is what it is. The main part of
this that will actually require intelligent thought is the column
wrapping and alignment. I think I will probably be implementing a
custom writer style thing to handle that.
There are a lot of annoying loose odds and ends here. Choice types
should list all the choices. But we can't necessarily assume that an
enum-typed parameter is a choice type (only if it uses the default
converter). Perhaps the conversion stuff should be turned into an
interface that can also be responsible for converting the default
value and providing additional information. For now I will probably
just hack it so that I can move on to other things.
This wasn't fully implemented, and I don't actually think there's a
real reason for it to exist. It was cargo culted over from my own
thinking about click functionality, but API differences mean it just
isn't really useful here.
the checklist of things to do is continuing to dwindle. hooray. last
big feature push is help text generation. Then improving error
reporting. Then writing some tests. Then writing documentation.
Ay carumba.
