@table @code
@item font-lock-warning-face
@vindex font-lock-warning-face
-for a construct that is peculiar, or that greatly changes the meaning of
+for a construct that is peculiar (e.g., an unescaped confusable quote
+in an Emacs Lisp symbol like @samp{‘foo}), or that greatly changes the meaning of
other text, like @samp{;;;###autoload} in Emacs Lisp and @samp{#error}
in C.
characters. However, you must add a backslash before any of the
characters @samp{()[]\;"}, and you should add a backslash before any
of the characters @samp{|'`#.,} to avoid confusing the Emacs commands
-for editing Lisp code. You can also add a backslash before whitespace
+for editing Lisp code. You should also add a backslash before Unicode
+characters which resemble the previously mentioned @acronym{ASCII}
+ones, to avoid confusing people reading your code. Emacs will
+highlight some non-escaped commonly confused characters such as
+@samp{‘} to encourage this. You can also add a backslash before whitespace
characters such as space, tab, newline and formfeed. However, it is
cleaner to use one of the easily readable escape sequences, such as
@samp{\t} or @samp{\s}, instead of an actual whitespace character such
<32252@debbugs.gnu.org>. Because '%o' and '%x' can now format signed
integers, they now support the '+' and space flags.
++++
+** In Emacs Lisp mode, symbols with confusable quotes are highlighted.
+For example, the first character in '‘foo' would be highlighted in
+'font-lock-warning-face'.
+
+++
** Omitting variables after '&optional' and '&rest' is now allowed.
For example '(defun foo (&optional))' is no longer an error. This is
(boundp var)
(memq var byte-compile-bound-variables)
(memq var byte-compile-free-references))
- (byte-compile-warn "reference to free variable `%S'" var)
+ (let* ((varname (prin1-to-string var))
+ (suggestions (help-uni-confusable-suggestions varname)))
+ (byte-compile-warn "reference to free variable `%s'%s" varname
+ (if suggestions (concat "\n " suggestions) "")))
(push var byte-compile-free-references))
(byte-compile-dynamic-variable-op 'byte-varref var))))
(boundp var)
(memq var byte-compile-bound-variables)
(memq var byte-compile-free-assignments))
- (byte-compile-warn "assignment to free variable `%s'" var)
+ (let* ((varname (prin1-to-string var))
+ (suggestions (help-uni-confusable-suggestions varname)))
+ (byte-compile-warn "assignment to free variable `%s'%s" varname
+ (if suggestions (concat "\n " suggestions) "")))
(push var byte-compile-free-assignments))
(byte-compile-dynamic-variable-op 'byte-varset var))))
(eq ?_ (aref (symbol-name var) 0))
;; As a special exception, ignore "ignore".
(eq var 'ignored))
- (byte-compile-warn "Unused lexical %s `%S'"
- varkind var)))
+ (let ((suggestions (help-uni-confusable-suggestions (symbol-name var))))
+ (byte-compile-warn "Unused lexical %s `%S'%s"
+ varkind var
+ (if suggestions (concat "\n " suggestions) "")))))
;; If it's unused, there's no point converting it into a cons-cell, even if
;; it's captured and mutated.
(`(,binder ,_ t t ,_)
`(face ,font-lock-warning-face
help-echo "This \\ has no effect"))))
+(defun lisp--match-confusable-symbol-character (limit)
+ ;; Match a confusable character within a Lisp symbol.
+ (catch 'matched
+ (while t
+ (if (re-search-forward uni-confusables-regexp limit t)
+ ;; Skip confusables which are backslash escaped, or inside
+ ;; strings or comments.
+ (save-match-data
+ (unless (or (eq (char-before (match-beginning 0)) ?\\)
+ (nth 8 (syntax-ppss)))
+ (throw 'matched t)))
+ (throw 'matched nil)))))
+
(let-when-compile
((lisp-fdefs '("defmacro" "defun"))
(lisp-vdefs '("defvar"))
(3 'font-lock-regexp-grouping-construct prepend))
(lisp--match-hidden-arg
(0 '(face font-lock-warning-face
- help-echo "Hidden behind deeper element; move to another line?")))
+ help-echo "Hidden behind deeper element; move to another line?")))
+ (lisp--match-confusable-symbol-character
+ 0 '(face font-lock-warning-face
+ help-echo "Confusable character"))
))
"Gaudy level highlighting for Emacs Lisp mode.")
(let ((print-escape-newlines t))
(help--docstring-quote (format "%S" (help--make-usage fn arglist)))))
+\f
+
+;; Just some quote-like characters for now. TODO: generate this stuff
+;; from official Unicode data.
+(defconst uni-confusables
+ '((#x2018 . "'") ;; LEFT SINGLE QUOTATION MARK
+ (#x2019 . "'") ;; RIGHT SINGLE QUOTATION MARK
+ (#x201B . "'") ;; SINGLE HIGH-REVERSED-9 QUOTATION MARK
+ (#x201C . "\"") ;; LEFT DOUBLE QUOTATION MARK
+ (#x201D . "\"") ;; RIGHT DOUBLE QUOTATION MARK
+ (#x201F . "\"") ;; DOUBLE HIGH-REVERSED-9 QUOTATION MARK
+ (#x301E . "\"") ;; DOUBLE PRIME QUOTATION MARK
+ (#xFF02 . "'") ;; FULLWIDTH QUOTATION MARK
+ (#xFF07 . "'") ;; FULLWIDTH APOSTROPHE
+ ))
+
+(defconst uni-confusables-regexp
+ (concat "[" (mapcar #'car uni-confusables) "]"))
+
+(defun help-uni-confusable-suggestions (string)
+ "Return a message describing confusables in STRING."
+ (let ((i 0)
+ (confusables nil))
+ (while (setq i (string-match uni-confusables-regexp string i))
+ (let ((replacement (alist-get (aref string i) uni-confusables)))
+ (push (aref string i) confusables)
+ (setq string (replace-match replacement t t string))
+ (setq i (+ i (length replacement)))))
+ (when confusables
+ (format-message
+ (if (> (length confusables) 1)
+ "Found confusable characters: %s; perhaps you meant: `%s'?"
+ "Found confusable character: %s, perhaps you meant: `%s'?")
+ (mapconcat (lambda (c) (format-message "`%c'" c))
+ confusables ", ")
+ string))))
+
+(defun help-command-error-confusable-suggestions (data _context _signal)
+ (pcase data
+ (`(void-variable ,var)
+ (let ((suggestions (help-uni-confusable-suggestions
+ (symbol-name var))))
+ (when suggestions
+ (princ (concat "\n " suggestions) t))))
+ (_ nil)))
+
+(add-function :after command-error-function
+ #'help-command-error-confusable-suggestions)
+
\f
(provide 'help)
(require 'ert)
(require 'cl-lib)
(require 'lisp-mode)
+(require 'faceup)
+
+\f
+;;; Indentation
(defconst lisp-mode-tests--correctly-indented-sexp "\
\(a
(insert "\"\n")
(lisp-indent-region (point-min) (point-max))))
+\f
+;;; Fontification
+
+(ert-deftest lisp-fontify-confusables ()
+ "Unescaped 'smart quotes' should be fontified in `font-lock-warning-face'."
+ (with-temp-buffer
+ (dolist (ch
+ '(#x2018 ;; LEFT SINGLE QUOTATION MARK
+ #x2019 ;; RIGHT SINGLE QUOTATION MARK
+ #x201B ;; SINGLE HIGH-REVERSED-9 QUOTATION MARK
+ #x201C ;; LEFT DOUBLE QUOTATION MARK
+ #x201D ;; RIGHT DOUBLE QUOTATION MARK
+ #x201F ;; DOUBLE HIGH-REVERSED-9 QUOTATION MARK
+ #x301E ;; DOUBLE PRIME QUOTATION MARK
+ #xFF02 ;; FULLWIDTH QUOTATION MARK
+ #xFF07 ;; FULLWIDTH APOSTROPHE
+ ))
+ (insert (format "«w:%c»foo \\%cfoo\n" ch ch)))
+ (let ((faceup (buffer-string)))
+ (faceup-clean-buffer)
+ (should (faceup-test-font-lock-buffer 'emacs-lisp-mode faceup)))))
+
(provide 'lisp-mode-tests)
;;; lisp-mode-tests.el ends here
projects / emacs.git / commitdiff