John Kitchin writes:
>> (setq python-font-lock-keywords
>> (append python-font-lock-keywords
>> '(;; this is the full string.
>> ;; group 1 is the quote type and a closing quote is matched
>> ;; group 2 is the string part
>> (
>> ;; "f\\(['\"]\\{1,3\\}\\)\\([^\\1]+?\\)\\1"
>> "f\\(['\"]\\{1,3\\}\\)\\(.+?\\)\\1"
>> ;; these are the {keywords}
>> ("{[^}]*?}"
>> ;; Pre-match form
>> (progn (goto-char (match-beginning 0)) (match-end 0))
>> ;; Post-match form
>> (goto-char (match-end 0))
>> ;; face for this match
>> (0 font-lock-variable-name-face t))))))
> Does anyone see anything wrong with that snippet? All it should do is
> improve font-lock on Python f-strings, and it used to work fine, but now it
> doesn't. It isn't real critical for me, so I don't mind commenting it out,
> but I neither understand why it stopped working!
I haven't tested to confirm, but I'd guess that is due to the
restructuring of python-font-lock-keywords in 36b64e087e (Add
'font-lock-maximum-decoration' levels for Python, 2018-07-19), which was
included in Emacs 27.
In case it's helpful, here's the compatibility kludge I used in
snakemake-mode:
https://git.kyleam.com/snakemake-mode/commit/snakemake-mode.el?id=5d5bb0109f6a84c0c191559ab71670fae4650e6a
