Make C++ digit separators work. Amend the handling of single quotes generally

Single quotes, even in strings and comments, are now marked with the
"punctuation" syntax-table property, except where they are validly bounding a
character literal.  They are font locked with font-lock-warning-face except
where they are valid.  This is done in C, C++, ObjC, and Java Modes.

* lisp/progmodes/cc-defs.el (c-clear-char-property-with-value-on-char-function)
(c-clear-char-property-with-value-on-char, c-put-char-properties-on-char): New
functions/macros.

* lisp/progmodes/cc-fonts.el (c-font-lock-invalid-single-quotes): New function.
(c-basic-matchers-before): invoke c-font-lock-invalid-single-quotes.

* lisp/progmodes/cc-langs.el (c-get-state-before-change-functions): Remove
c-before-after-change-digit-quote from wherever it occurs.  Insert
c-parse-quotes-before-change into the entries for the languages where it is
needed.
(c-before-font-lock-functions): Remove c-before-after-change-digit-quote from
wherever it occurs.  Insert c-parse-quotes-after-change into the entries for
the languages which need it.
(c-has-quoted-numbers): New lang-defconst/-defvar.

* lisp/progmodes/cc-mode.el (c-before-after-change-digit-quote): Remove.
(c-maybe-quoted-number-head, c-maybe-quoted-number-tail)
(c-maybe-quoted-number): New defconsts.
(c-quoted-number-head-before-point, c-quoted-number-tail-after-point)
(c-quoted-number-straddling-point, c-parse-quotes-before-change)
(c-parse-quotes-after-change): New functions.

1 files changed, 33 insertions, 0 deletions

diff --git a/lisp/progmodes/cc-fonts.el b/lisp/progmodes/cc-fonts.el
index 00812530357..66f2575f49f 100644
--- a/lisp/progmodes/cc-fonts.el
+++ b/lisp/progmodes/cc-fonts.el
@@ -702,6 +702,36 @@ stuff.  Used on level 1 and higher."
 	     t)
 	   (c-put-font-lock-face start (1+ start) 'font-lock-warning-face)))))
 
+(defun c-font-lock-invalid-single-quotes (limit)
+  ;; This function will be called from font-lock for a region bounded by POINT
+  ;; and LIMIT, as though it were to identify a keyword for
+  ;; font-lock-keyword-face.  It always returns NIL to inhibit this and
+  ;; prevent a repeat invocation.  See elisp/lispref page "Search-based
+  ;; Fontification".
+  ;;
+  ;; This function fontifies invalid single quotes with
+  ;; `font-lock-warning-face'.  These are the single quotes which
+  ;; o - aren't inside a literal;
+  ;; o - are marked with a syntax-table text property value '(1); and
+  ;; o - are NOT marked with a non-null c-digit-separator property.
+  (let ((limits (c-literal-limits))
+	state beg end)
+    (if limits
+	(goto-char (cdr limits)))	; Even for being in a ' '
+    (while (< (point) limit)
+      (setq beg (point))
+      (setq state (parse-partial-sexp (point) limit nil nil nil 'syntax-table))
+      (setq end (point))
+      (goto-char beg)
+      (while (progn (skip-chars-forward "^'" end)
+		    (< (point) end))
+	(if (and (equal (c-get-char-property (point) 'syntax-table) '(1))
+		 (not (c-get-char-property (point) 'c-digit-separator)))
+	    (c-put-font-lock-face (point) (1+ (point)) font-lock-warning-face))
+	(forward-char))
+      (parse-partial-sexp end limit nil nil state 'syntax-table)))
+    nil)
+
 (c-lang-defconst c-basic-matchers-before
   "Font lock matchers for basic keywords, labels, references and various
 other easily recognizable things that should be fontified before generic
@@ -723,6 +753,9 @@ casts and declarations are fontified.  Used on level 2 and higher."
 	(concat ".\\(" c-string-limit-regexp "\\)")
 	'((c-font-lock-invalid-string)))
 
+      ;; Invalid single quotes.
+      c-font-lock-invalid-single-quotes
+
       ;; Fontify C++ raw strings.
       ,@(when (c-major-mode-is 'c++-mode)
 	  '(c-font-lock-raw-strings))