Syntactic fontification uses a syntax table (see Syntax Tables) to
find and highlight syntactically relevant text. If enabled, it runs
prior to search-based fontification. The variable
font-lock-syntactic-face-function, documented below, determines
which syntactic constructs to highlight. There are several variables
that affect syntactic fontification; you should set them by means of
font-lock-defaults (see Font Lock Basics).
Whenever Font Lock mode performs syntactic fontification on a stretch
of text, it first calls the function specified by
syntax-propertize-function. Major modes can use this to apply
syntax-table text properties to override the buffer’s syntax
table in special cases. See Syntax Properties.
If the value of this variable is non-nil, Font Lock does not do
syntactic fontification, only search-based fontification based on
font-lock-keywords. It is normally set by Font Lock mode based
on the keywords-only element in font-lock-defaults. If
the value is nil, Font Lock will call jit-lock-register
(see Other Font Lock Variables) to set up for automatic
refontification of buffer text following a modified line to reflect
the new syntactic context due to the change.
To use only syntactic fontification, this variable should
be non-nil, while font-lock-keywords should be set to
nil (see Font Lock Basics).
This variable holds the syntax table to use for fontification of
comments and strings. It is normally set by Font Lock mode based on the
syntax-alist element in font-lock-defaults. If this value
is nil, syntactic fontification uses the buffer’s syntax table
(the value returned by the function syntax-table; see Syntax Table Functions).
If this variable is non-nil, it should be a function to determine
which face to use for a given syntactic element (a string or a comment).
The function is called with one argument, the parse state at point
returned by parse-partial-sexp, and should return a face. The
default value returns font-lock-comment-face for comments and
font-lock-string-face for strings (see Faces for Font Lock).
This variable is normally set through the “other” elements in
font-lock-defaults:
(setq-local font-lock-defaults
`(,python-font-lock-keywords
nil nil nil nil
(font-lock-syntactic-face-function
. python-font-lock-syntactic-face-function)))