Expose internals of AttributePredicate

[isovector]

I'd like to write a selector that can match on any class that contains a particular word. The exposed interface to scalpel isn't sufficient to accomplish this, but it's clear that the internals are capable.

[fimad]

I think you could achieve that with either match which lets you create arbitrary attribute predicates or (@=~) which allows you to specify a regex for matching attribute values.

https://hackage.haskell.org/package/scalpel-core-0.6.2/docs/Text-HTML-Scalpel-Core.html#g:4