Multiple validators? about attrs

[mjmare]

Oh, and if one wants an attrib to be required, that has to be implemented with a validator?

[hynek]

attrs comes with two validators: https://attrs.readthedocs.org/en/stable/api.html#validators . Calling them a “bunch” may be a bit of a stretch but I didn’t want to reword once they grow. :)

I had some code in place for anding and oring validators but it felt a bit academic so I took it out for now again until I come up with a compelling use case.

Attributes are always required unless you supply a default value.

[mjmare]

and/or validators seem pretty useful to me in order to make validators more granular. But other validator will likely be needed more, like ranges, or select from list or...

[econchick]

@mjmare (not a maintainer, just an avid user of attrs) - you can write & supply your own validators and not rely on @hynek to write more default ones.

For instance, I've written a lot of validators for ramlfications - an example: the version of the RootNode validates with this function.

Not sure if that helps at all 😄 but attrs' validation is definitely one of the main reasons I chose this library when writing my library.

[hynek]

…and you can totally put them on PyPI either if you think they’re generally useful. :) I’m trying to learn from the mistakes I did with characteristic and keep the scope small on purpose while giving users ways to extend attrs to their liking.