For example, "property.br\u{64}wn" should resolve to "property.brown".
To support this behavior, this commit changes the Token class to hold
both the evaluated identifier name and a view into the original source
for the unevaluated name. There are some contexts in which identifiers
are not allowed to contain Unicode escape sequences; for example, export
statements of the form "export {} from foo.js" forbid escapes in the
identifier "from".
The test file is added to .prettierignore because prettier will replace
all escaped Unicode sequences with their unescaped value.
Unfortunately, this requires a slight divergence in the way the capture
group names are stored. Previously, the generated byte code would simply
store a view into the regex pattern string, so no string copying was
required.
Now, the escape sequences are decoded into a new string, and a vector
of all parsed capture group names are stored in a vector in the parser
result structure. The byte code then stores a view into the
corresponding string in that vector.
Instead of constructing a String and converting that to a PropertyName
on the fly, we can just leverage CommonPropertyNames, add a couple more
and directly pass ready-to-use PropertyNames with pre-allocated Strings.
This is a small step in the right direction although the amount of
different checks is becoming unsustainable. In the future we probably
want to have the current_scope handle all declarations.
Combining these into one list helps reduce the size of MatchState, and
as a result, reduces the amount of memory consumed during execution of
very large regex matches.
Doing this also allows us to remove a few regex byte code instructions:
ClearNamedCaptureGroup, SaveLeftNamedCaptureGroup, and NamedReference.
Named groups now behave the same as unnamed groups for these operations.
Note that SaveRightNamedCaptureGroup still exists to cache the matched
group name.
This also removes the recursion level from the MatchState, as it can
exist as a local variable in Matcher::execute instead.
The check for stack space in VM from push_execution_context has been
moved to a method on VM called did_reach_stack_space_limit. This
allows us to check the stack size in other places besides
push_execution_context.
We can now verify that we have enough space on the stack before calling
flatten_into_array to ensure that we don't cause a stack overflow error
when calling the function with a large depth.
