Safari and negative look-behinds

[hildjj]

Safari doesn't support negative look-behind assertions of the form (?<!y)x. That's pretty awful.

It makes this line fail to parse:

const strEscapeSequencesRegExp = /[\x00-\x1f\x27\x5c\x7f-\x9f]|[\ud800-\udbff](?![\udc00-\udfff])|(?<![\ud800-\udbff])[\udc00-\udfff]/;

which makes the global variable util not available.

See peggyjs/peggy#371

[hildjj]

This will be fixed in Safari 16.4. I wonder if Peggy can work around it until then.

[hildjj]

I decided to just go ahead and fix this, even though the fix was u-g-l-y.