QualName should have a prefix member

[Ms2ger]

There doesn't seem to be a good reason to omit that.

[kmcallister]

The main drawback is that it will make QualName 50% bigger. We usually don't care about prefixes and don't use them in comparison, although I guess we have to thread them through everywhere.

I'd actually like to intern common triples of (local name, namespace, prefix) as a single 64-bit word. The problem then is how to efficiently compare these while ignoring the prefix.

Is it possible for a name in the HTML namespace to have a non-empty prefix? I don't think there's any way to express those in the HTML syntax, but I suppose it can be done in XHTML.

[SimonSapin]

Indeed not with HTML syntax, but anything is possible in XML syntax (XHTML) or through DOM manipulation.

[SimonSapin]

That said, such rare case don’t have to be fast as long as they’re correct.

[chotchki]

@kmcallister would this be considered an easy fix?

[SimonSapin]

Indeed not with HTML syntax

Correction: the HTML parser does emit non-empty prefixes in some cases: https://html.spec.whatwg.org/multipage/#adjust-foreign-attributes

[nicoburns]

Closing as string_cache no longer has a QualName type (since the 0.3.0 in Nov 2016). Furthermore, the QualName type in markup5ever which replaced it has a prefix member.