Implement parsing of rgb(..) and hsl(..) in both the modern level 4
syntax without commas, and the legacy syntax with commas.
The parser accepts non-integer numbers but rounds to integer values
for now.
Previously, `var()` inside functions like `rgb()` wasn't resolved.
This will set the background color for badges in the New category on
https://ports.serenityos.net. :^)
When parsing <ndash-dimension> <signless-integer>, we tried to parse
a new token from the stream instead of using the value we had already
extracted. This caused pages that used the syntax to crash.
...and change how the two parsing steps fit together.
The two steps were previously quite muddled. Both worked with the
TokenStream directly, and both were responsible for rewinding that
stream if there was an error. This is both confusing and also made it
impossible to replace the rewinding with StateTransactions.
This commit more clearly divides the work between the two functions: One
parses ComponentValues and produces a string, and the other parses that
string to produce the UnicodeRange. It also replaces manual rewinding
in the former with StateTransactions.
This should be a bit easier to follow.
parse_media_query() no longer rewinds if the media query is invalid,
because it then interprets all the tokens as a "not all" query.
This is modeled after the one in ISO8601Parser. It rolls back the
TokenStream state automatically at the end of scope unless told to
commit the changes. This should be less error-prone than remembering to
manually call `rewind_to_position()` at the correct time.
For convenience, a StateTransaction can have "child" transactions. When
a transaction is committed, it automatically commits its parents too.
This is useful in situations where you have several nested and don't
want to have to remember to manually `commit()` them all.
`a` and `b` had to be declared at the top of the function before since
they were used by the `make_return_value()` lambda. But now that
doesn't exist, we can move them to where they are used - or eliminate
them entirely.
parse_a_n_plus_b_pattern()'s job is to parse as much of the TokenStream
as it can as a An+B, and then stop. The caller can then deal with any
trailing tokens as it wishes.
...using a ParseErrorOr type alias.
This lets us replace a bunch of manual error-checking with TRY. :^)
I also replaced the ParsingResult::Done value with returning an
Optional. I wasn't happy with treating "Done" as an error when I first
wrote this, and this makes a clear distinction between the two.
The spec grammar for `text-decoration-line` is:
`none | [ underline || overline || line-through || blink ]`
Which means that it's either `none`, or any combination of the other
values. This patch makes that parse for `text-decoration-line` and
`text-decoration`, stores the results as a Vector, and adjusts
`paint_text_decoration()` to run as a loop over all the values that are
provided.
As noted, storing a Vector of values is a bit wasteful, as they could be
stored as flags in a single `u8`. But I was getting too confused trying
to do that in a nice way.
As before, this requires deviating from the spec slightly to create the
StyleRule fully-formed instead of creating it empty and then modifying
its internals.
This means deviating slightly from the spec in order to construct a
fully-initialized Declaration instead of creating an empty one and then
poking at its internals.
DeclarationOrAtRule should probably use a Variant, but for now, making
its Declaration member optional is quick and easy.
This means deviating a little from the spec, so that we create a
complete Block in one go instead of creating an empty one and then
poking at its internals.
