Support FLAT mode in config file

[RmZeta2718]

Is your feature request related to a problem? Please describe.
As far as I know, when using composition dataclasses, I can only specify the full destination structure in the config file. Flat arguments are only available in the command line.

Describe the solution you'd like

It would be great if config file supports flat arguments for composition dataclasses:

So the example (examples/config_files/composition_defaults.yaml) can be modified to:

a: "default value for `a` from the Parser's `config_path` (composition_defaults.yaml)"
b: "default value for `b` from the Parser's `config_path` (composition_defaults.yaml)"
c: "default value for `c` from the Parser's `config_path` (composition_defaults.yaml)"

Additional context
env:

• python 3.11
• simple-parsing 0.1.6

[lebrice]

Hey @RmZeta2718 , thanks for posting, sorry for the late reply.

This is interesting, but sounds a bit too specific to config files and serialization. I don't see a way to realistically add this at the moment. Feel free to give this a shot though if you're up for it!