(concat js--name-re "\\(?:\\." js--name-re "\\)*")
"Regexp matching a dot-separated sequence of JavaScript names.")
+(defconst js--dotted-captured-name-re
+ (concat "\\(" js--name-re "\\)\\(?:\\." js--name-re "\\)*")
+ "Like `js--dotted-name-re', but capture the first name.")
+
(defconst js--cpp-name-re js--name-re
"Regexp matching a C preprocessor name.")
'syntax-table (string-to-syntax "\"/"))
(goto-char end)))))
+(defconst js--unary-keyword-re
+ (js--regexp-opt-symbol '("await" "delete" "typeof" "void" "yield"))
+ "Regexp matching unary operator keywords.")
+
+(defun js--unary-keyword-p (string)
+ "Check if STRING is a unary operator keyword in JavaScript."
+ (string-match-p js--unary-keyword-re string))
+
+(defun js--disambiguate-beginning-of-jsx-tag ()
+ "Parse enough to determine if a JSX tag starts here.
+Disambiguate JSX from equality operators by testing for syntax
+only valid as JSX."
+ ;; “</…” - a JSXClosingElement.
+ ;; “<>” - a JSXOpeningFragment.
+ (if (memq (char-after) '(?\/ ?\>)) t
+ (save-excursion
+ (skip-chars-forward " \t\n")
+ (and
+ (looking-at js--dotted-captured-name-re)
+ ;; Don’t match code like “if (i < await foo)”
+ (not (js--unary-keyword-p (match-string 1)))
+ (progn
+ (goto-char (match-end 0))
+ (skip-chars-forward " \t\n")
+ (or
+ ;; “>”, “/>” - tag enders.
+ ;; “{” - a JSXExpressionContainer.
+ (memq (char-after) '(?\> ?\/ ?\{))
+ ;; Check if a JSXAttribute follows.
+ (looking-at js--name-start-re)))))))
+
+(defun js--disambiguate-end-of-jsx-tag ()
+ "Parse enough to determine if a JSX tag ends here.
+Disambiguate JSX from equality operators by testing for syntax
+only valid as JSX, or extremely unlikely except as JSX."
+ (save-excursion
+ (backward-char)
+ ;; “…/>” - a self-closing JSXOpeningElement.
+ ;; “</>” - a JSXClosingFragment.
+ (if (= (char-before) ?/) t
+ (let (last-tag-or-attr-name last-non-unary-p)
+ (catch 'match
+ (while t
+ (skip-chars-backward " \t\n")
+ ;; Check if the end of a JSXAttribute value or
+ ;; JSXExpressionContainer almost certainly precedes.
+ ;; The only valid JS this misses is
+ ;; - {} > foo
+ ;; - "bar" > foo
+ ;; which is no great loss, IMHO…
+ (if (memq (char-before) '(?\} ?\" ?\' ?\`)) (throw 'match t)
+ (if (and last-tag-or-attr-name last-non-unary-p
+ ;; “<”, “</” - tag starters.
+ (memq (char-before) '(?\< ?\/)))
+ ;; Leftmost name parsed was the name of a
+ ;; JSXOpeningElement.
+ (throw 'match t))
+ ;; Technically the dotted name could span multiple
+ ;; lines, but dear God WHY?! Also, match greedily to
+ ;; ensure the entire name is valid.
+ (if (looking-back js--dotted-captured-name-re (point-at-bol) t)
+ (if (and (setq last-non-unary-p (not (js--unary-keyword-p (match-string 1))))
+ last-tag-or-attr-name)
+ ;; Valid (non-unary) name followed rightwards by
+ ;; another name (any will do, including
+ ;; keywords) is invalid JS, but valid JSX.
+ (throw 'match t)
+ ;; Remember match and skip backwards over it when
+ ;; it is the first matched name or the N+1th
+ ;; matched unary name (unary names on the left are
+ ;; still ambiguously JS or JSX, so keep parsing to
+ ;; disambiguate).
+ (setq last-tag-or-attr-name (match-string 1))
+ (goto-char (match-beginning 0)))
+ ;; Nothing else to look for; give up parsing.
+ (throw 'match nil)))))))))
+
+(defun js--disambiguate-js-from-jsx (start end)
+ "Figure out which ‘<’ and ‘>’ chars (from START to END) aren’t JSX.
+
+Later, this info prevents ‘sgml-’ functions from treating some
+‘<’ and ‘>’ chars as parts of tokens of SGML tags — a good thing,
+since they are serving their usual function as some JS equality
+operator or arrow function, instead."
+ (goto-char start)
+ (while (re-search-forward "[<>]" end t)
+ (unless (if (eq (char-before) ?<) (js--disambiguate-beginning-of-jsx-tag)
+ (js--disambiguate-end-of-jsx-tag))
+ ;; Inform sgml- functions that this >, >=, >>>, <, <=, <<<, or
+ ;; => token is punctuation (and not an open or close parenthesis
+ ;; as per usual in sgml-mode).
+ (put-text-property (1- (point)) (point) 'syntax-table '(1)))))
+
(defun js-syntax-propertize (start end)
;; JavaScript allows immediate regular expression objects, written /.../.
(goto-char start)
'syntax-table (string-to-syntax "\"/"))
(js-syntax-propertize-regexp end)))))
("\\`\\(#\\)!" (1 "< b")))
- (point) end))
+ (point) end)
+ (if js-jsx-syntax (js--disambiguate-js-from-jsx start end)))
(defconst js--prettify-symbols-alist
'(("=>" . ?⇒)
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