fix: Centralize command setup code.

[DanCardin]

Adds a (currently undocumented and not explicitly exported collect function in cappa.base.

Upon seeing #30, it occurred to me that at the very least there's a decent chunk of code being duplicated between argparse and the native backend.

• It makes the code simpler, reusing more between the parsers
• because it moves logic upstream of argeparse that was previously built into the native parger, it enables using the "native" rich help text generation when using the argparse backend
• incidentally it also helps simplify the situation in question: Forcing colors? #30 which required a decent chunk of code to output help text without also performing parsing.

[coveralls]

Pull Request Test Coverage Report for Build 6603742067

• 38 of 38 (100.0%) changed or added relevant lines in 5 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 100.0%

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Totals
Change from base Build 6603736997:	0.0%
Covered Lines:	1558
Relevant Lines:	1558

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💛 - Coveralls

[pawamoy]

Great! IIUC, we can now do this?

from cappa.base import collect
from cappa.help import format_help
from cappa.output import Output

from pkg.cli import CommandMain

Output.from_theme().output(format_help(collect(CommandMain)))

[DanCardin]

Yup! Probably once i've decided its "done", collect will be exposed at the root of the package. I'm not thrilled necessarily at how it currently composes with parse and such, but tl;dr yes :P

[pawamoy]

OK, great! I've opened #35 as a follow up 🙂