Sublime Text syntax: Python 3.6 f-strings

Question

I am trying to modify the default Python.sublime_syntax file to handle Python’s f-string literals properly. My goal is to have expressions in interpolated strings recognised as such:

f"hello {person.name if person else 'there'}"
         -----------source.python----------
------string.quoted.double.block.python------

Within f-strings, ranges of text between a single { and another } (but terminating before format specifiers such as !r}, :<5}, etc—see PEP 498) should be recognised as expressions. As far as I know, that might look a little like this:

...
string:
 - match: "(?<=[^\{]\{)[^\{].*)(?=(!(s|r|a))?(:.*)?\})" # I'll need a better regex
   push: expressions

However, upon inspecting the build-in Python.sublime_syntax file, the string contexts especially are to unwieldy to even approach (~480 lines?) and I have no idea how to begin. Thanks heaps for any info.

Answer 1

There was an update to syntax highlighting in BUILD 3127 (Which includes: Significant improvements to Python syntax highlighting).

However, a couple users have stated that in BUILD 3176 syntax highlighting still is not set to correctly highlight Python expressions that are located within f strings. According to @Jollywatt, it is set to source.python f"string.quoted.double.block {constant.other.placeholder}" rather than f"string.quoted.double.block {source.python}"

It looks like Sublime uses this tool, PackageDev, "to ease the creation of snippets, syntax definitions, etc. for Sublime Text."