This is a weird behaviour specific to `font` - it can reset some
properties that it never actually sets. As such, it didn't seem worth
adding this concept to the code generator, but just manually stuffing
the ShorthandStyleValue with them during parsing.
This file has been a pain to edit for a while, even with the previous
splits. So, I've divided it up into 3 parts:
- Parser.cpp has the "base" code. It's the algorithms and entry-points
defined in the Syntax spec.
- ValueParsing.cpp contains code for parsing single values, such as a
length, or a color, or a calculation.
- PropertyParsing.cpp contains code for parsing an entire property's
value. A few of these sit in a grey area between being a property's
value and a value in their own right, but the rule I've used is "is
this useful outside of a single property and its shorthands?"
This only moves code, with as few modifications as possible to make that
work. I did add explicit instantiations for the template implementations
as part of this, which revealed a few that are actually only compatible
with a single type, so I'll clear those up in a subsequent commit.
