Feature Request: Rule metadata

[danielcrane]

It'd be great if rules could be provided metadata, similarly to how columns can, to be able to pass for example a description of the rule that could be programmatically accessed from elsewhere.

i.e. @dy.rule(metadata={'description': 'xxx'})

Alternatively, allowing the rule's docstring to override the Rule class docstring could also work -- i.e. via one of the following solutions: https://stackoverflow.com/a/68733424 (which would allow one to do Schema.rule_func.__doc__ to get the docstring).

[borchero]

Out of curiosity: what's your use case for the metadata argument?

[danielcrane]

Thanks for your response!

Frankly right now the only use-case I have is for adding a description to the rule.

This would be useful to allow me to for example (programmatically) walk through the Schema's rules and generate a catalogue of rules with descriptions.

I'm currently storing descriptions in a config file, which works, but it'd be more elegant to be able to store it in-line with the function itself.

The alternative I mentioned (using functools to propagate the doc from the validation function) would work fine too for my specific use-case.