Specificity not supported about premailer

[peterbe]

Does lxml support :last-child selectors?

Also, since the parse reads from the top to bottom. Can't you just change the order of your two selectors?

[gavinwahl]

It does support that selector; reversing the order does give the expected behavior. So you can 'just' sort your selectors by specificity, but I don't think you can say you really have CSS without the cascade.

[elidickinson]

@peterbe I haven't dug in very deeply, but is there any reason premailer is trying to calculate specificity itself in _parse_style_rules rather than using the functionality provided by cssselect: https://pythonhosted.org/cssselect/#cssselect.Selector.specificity ?

[peterbe]

@elidickinson I don't know but I suspect that history will explain that. There used to be just lxml but later someone broke that out of lxml and we then have to install both lxml and cssselect. It came into existence late and that's probably simply the explanation.

Do you think you'd be able to write a little patch to switch to using cssselect instead of the ad-hoc custom code? I'd be willing to help and help write some tests.

[elidickinson]

@peterbe Makes sense, I think I actually knew that and forgot. Yeah, I'll take a swing at it. Writing the tests is probably exactly where I'd need the help. Might take me a bit before I can get to it, though.

[peterbe]

@elidickinson Please do not hesitate to ping me. Writing the tests is going to be easy. But if you're not super familiar with it the project it can be hard to know how to start the tests or where to put the new tests (hint; it's mainly copy-n-paste from some existing test).