From 5881c2e98d9457e04f6502921ab1cbe7a8e74ef5 Mon Sep 17 00:00:00 2001 From: Dario Gjorgjevski Date: Sun, 20 Dec 2020 17:12:01 +0100 Subject: [PATCH] Make python-mode fontify more assignment statements The current implementation in python-mode fontifies only basic assignment statements. It makes mistakes on or entirely misses more complex ones such as [a, b, c] = 1, 2, 3 a, *b, c = range(10) inst.a, inst.b, inst.c = 'foo', 'bar', 'baz' (a, b, *c, d) = x, *y = 5, 6, 7, 8, 9 This commit extends the fontification to work correctly with all these cases. * lisp/progmodes/python.el (python-font-lock-assignment-matcher): New function to match assignment statements. (python-rx): Add `assignment-target' and `grouped-assignment-target'. (python-font-lock-keywords-maximum-decoration): Add new matchers. --- lisp/progmodes/python.el | 96 +++++++++++++++++++++++++++++----------- 1 file changed, 69 insertions(+), 27 deletions(-) diff --git a/lisp/progmodes/python.el b/lisp/progmodes/python.el index d58b32f3c3..50bb841111 100644 --- a/lisp/progmodes/python.el +++ b/lisp/progmodes/python.el @@ -394,6 +394,12 @@ python-rx (any ?' ?\") "__main__" (any ?' ?\") (* space) ?:)) (symbol-name (seq (any letter ?_) (* (any word ?_)))) + (assignment-target (seq (? ?*) + (* symbol-name ?.) symbol-name + (? ?\[ (+ (not ?\])) ?\]))) + (grouped-assignment-target (seq (? ?*) + (* symbol-name ?.) (group symbol-name) + (? ?\[ (+ (not ?\])) ?\]))) (open-paren (or "{" "[" "(")) (close-paren (or "}" "]" ")")) (simple-operator (any ?+ ?- ?/ ?& ?^ ?~ ?| ?* ?< ?> ?= ?%)) @@ -605,6 +611,18 @@ python-font-lock-keywords-level-2 `python-font-lock-keywords-level-1', as well as keywords and builtins.") +(defun python-font-lock-assignment-matcher (regexp) + "Font lock matcher for assignments based on REGEXP. +Return nil if REGEXP matched within a `paren' context (to avoid, +e.g., default values for arguments or passing arguments by name +being treated as assignments) or is followed by an '=' sign (to +avoid '==' being treated as an assignment." + (lambda (limit) + (let ((res (re-search-forward regexp limit t))) + (unless (or (python-syntax-context 'paren) + (equal (char-after (point)) ?=)) + res)))) + (defvar python-font-lock-keywords-maximum-decoration `((python--font-lock-f-strings) ,@python-font-lock-keywords-level-2 @@ -652,33 +670,57 @@ python-font-lock-keywords-maximum-decoration ) symbol-end) . font-lock-type-face) - ;; assignments - ;; support for a = b = c = 5 - (,(lambda (limit) - (let ((re (python-rx (group symbol-name) - ;; subscript, like "[5]" - (? ?\[ (+ (not ?\])) ?\]) (* space) - ;; type hint, like ": int" or ": Mapping[int, str]" - (? ?: (* space) (+ not-simple-operator) (* space)) - assignment-operator)) - (res nil)) - (while (and (setq res (re-search-forward re limit t)) - (or (python-syntax-context 'paren) - (equal (char-after (point)) ?=)))) - res)) - (1 font-lock-variable-name-face nil nil)) - ;; support for a, b, c = (1, 2, 3) - (,(lambda (limit) - (let ((re (python-rx (group symbol-name) (* space) - (* ?, (* space) symbol-name (* space)) - ?, (* space) symbol-name (* space) - assignment-operator)) - (res nil)) - (while (and (setq res (re-search-forward re limit t)) - (goto-char (match-end 1)) - (python-syntax-context 'paren))) - res)) - (1 font-lock-variable-name-face nil nil))) + ;; multiple assignment + ;; (note that type hints are not allowed for multiple assignments) + ;; a, b, c = 1, 2, 3 + ;; a, *b, c = 1, 2, 3, 4, 5 + ;; [a, b] = (1, 2) + ;; (l[1], l[2]) = (10, 11) + ;; (a, b, c, *d) = *x, y = 5, 6, 7, 8, 9 + ;; (a,) = 'foo' + ;; (*a,) = ['foo', 'bar', 'baz'] + ;; d.x, d.y[0], *d.z = 'a', 'b', 'c', 'd', 'e' + ;; and variants thereof + ;; the cases + ;; (a) = 5 + ;; [a] = 5 + ;; [*a] = 5, 6 + ;; are handled separately below + (,(python-font-lock-assignment-matcher + (python-rx (? (or "[" "(") (* space)) + grouped-assignment-target (* space) ?, (* space) + (* assignment-target (* space) ?, (* space)) + (? assignment-target (* space)) + (? ?, (* space)) + (? (or ")" "]") (* space)) + (group assignment-operator))) + (1 font-lock-variable-name-face) + (,(python-rx grouped-assignment-target) + (progn + (goto-char (match-end 1)) ; go back after the first symbol + (match-beginning 2)) ; limit the search until the assignment + nil + (1 font-lock-variable-name-face))) + ;; single assignment with type hints, e.g. + ;; a: int = 5 + ;; b: Tuple[Optional[int], Union[Sequence[str], str]] = (None, 'foo') + ;; c: Collection = {1, 2, 3} + ;; d: Mapping[int, str] = {1: 'bar', 2: 'baz'} + (,(python-font-lock-assignment-matcher + (python-rx grouped-assignment-target (* space) + (? ?: (* space) (+ not-simple-operator) (* space)) + assignment-operator)) + (1 font-lock-variable-name-face)) + ;; special cases + ;; (a) = 5 + ;; [a] = 5 + ;; [*a] = 5, 6 + (,(python-font-lock-assignment-matcher + (python-rx (or "[" "(") (* space) + grouped-assignment-target (* space) + (or ")" "]") (* space) + assignment-operator)) + (1 font-lock-variable-name-face))) "Font lock keywords to use in python-mode for maximum decoration. This decoration level includes everything in -- 2.28.0