+
+;; C preprocessor(cpp) is used outside of C, C++ and Objective-C source file.
+;; e.g. assembler code and GNU linker script in Linux kernel.
+;; `cpp-font-lock-keywords' is handy for modes for the files.
+;;
+;; Here we cannot use `regexp-opt' because because regex-opt is not preloaded
+;; while font-lock.el is preloaded to emacs. So values pre-calculated with
+;; regexp-opt are used here.
+
+;; `cpp-font-lock-keywords-source-directives' is calculated from:
+;;
+;; (regexp-opt
+;; '("define" "elif" "else" "endif" "error" "file" "if" "ifdef"
+;; "ifndef" "import" "include" "line" "pragma" "undef" "warning"))
+;;
+(defconst cpp-font-lock-keywords-source-directives
+ "define\\|e\\(?:l\\(?:if\\|se\\)\\|ndif\\|rror\\)\\|file\\|i\\(?:f\\(?:n?def\\)?\\|mport\\|nclude\\)\\|line\\|pragma\\|undef\\|warning"
+ "Regular expressoin used in `cpp-font-lock-keywords'.")
+
+;; `cpp-font-lock-keywords-source-depth' is calculated from:
+;;
+;; (regexp-opt-depth (regexp-opt
+;; '("define" "elif" "else" "endif" "error" "file" "if" "ifdef"
+;; "ifndef" "import" "include" "line" "pragma" "undef" "warning")))
+;;
+(defconst cpp-font-lock-keywords-source-depth 0
+ "An integer representing regular expression depth of `cpp-font-lock-keywords-source-directives'.
+Used in `cpp-font-lock-keywords'.")
+
+(defconst cpp-font-lock-keywords
+ (let* ((directives cpp-font-lock-keywords-source-directives)
+ (directives-depth cpp-font-lock-keywords-source-depth))
+ (list
+ ;;
+ ;; Fontify error directives.
+ '("^#[ \t]*\\(?:error\\|warning\\)[ \t]+\\(.+\\)" 1 font-lock-warning-face prepend)
+ ;;
+ ;; Fontify filenames in #include <...> preprocessor directives as strings.
+ '("^#[ \t]*\\(?:import\\|include\\)[ \t]*\\(<[^>\"\n]*>?\\)"
+ 1 font-lock-string-face prepend)
+ ;;
+ ;; Fontify function macro names.
+ '("^#[ \t]*define[ \t]+\\([[:alpha:]_][[:alnum:]_$]*\\)("
+ (1 font-lock-function-name-face prepend)
+ ;;
+ ;; Macro arguments.
+ ((lambda (limit)
+ (re-search-forward
+ "\\(?:\\([[:alpha:]_][[:alnum:]_]*\\)[,]?\\)"
+ (or (save-excursion (re-search-forward ")" limit t))
+ limit)
+ t))
+ nil nil (1 font-lock-variable-name-face prepend)))
+ ;;
+ ;; Fontify symbol names in #elif or #if ... defined preprocessor directives.
+ '("^#[ \t]*\\(?:elif\\|if\\)\\>"
+ ("\\<\\(defined\\)\\>[ \t]*(?\\([[:alpha:]_][[:alnum:]_]*\\)?" nil nil
+ (1 font-lock-builtin-face prepend) (2 font-lock-variable-name-face prepend t)))
+ ;;
+ ;; Fontify otherwise as symbol names, and the preprocessor directive names.
+ (list
+ (concat "^\\(#[ \t]*\\(?:" directives
+ "\\)\\)\\>[ \t!]*\\([[:alpha:]_][[:alnum:]_]*\\)?")
+ '(1 font-lock-preprocessor-face prepend)
+ (list (+ 2 directives-depth)
+ 'font-lock-variable-name-face nil t))))
+ "Font lock keyords for C preprocessor directives.
+`c-mode', `c++-mode' and `objc-mode' have their own
+font lock keyords for C preprocessor directives. This definition is for the
+other modes in which C preprocessor directives are used. e.g. `asm-mode' and
+`ld-script-mode'.")
+