Scoped global config

[jorenham]

Useful for globally or temporarily overriding defaults, e.g. those used for kwargs such as dtype, trim, cache, sort, rowvar, n_extra, etc.

See polars.Config for a similar feature in polars with a clean API.

Usage

Global config:

Setting:

lmo.config.set(sort='stable')

Local config

with lmo.config(sort='stable'):
    ...

or

@lmo.config.override(sort='stable')
def spam(...):
    ...

Implementation

• The code will live in a new lmo.config namespace.
• Specify the config options using a class ConfigOptions(TypedDict, total=False): ....
• Use a _CONFIG: collections.ChainMap for global config (although maybe an alternative or subclass is needed for TypedDict support).
• Initialize the root of _CONFIG using default values.
• Implement lmo.config.override(**options: *ConfigOptions) contextmanager + decorator by having it push/pop from _CONFIG.
• Implement lmo.config.set(*ConfigOptions) by replacing the root _CONFIG, so that any potential locally overridden options aren't affected

Bonus feature: Environment variables

So that e.g. LMO_SORT="stable" can be used to specifiy sort='stable' (supersedes the root config).

Bonus feature: pyproject.toml

Something like

[tool.lmo]
sort = "stable"

It should have lower priorty than the environment variables.