Introduce a new comment style "c" flag.

* src/syntax.c (SYNTAX_FLAGS_COMMENT_STYLEB)
(SYNTAX_FLAGS_COMMENT_STYLEC): New macros.
(SYNTAX_FLAGS_COMMENT_STYLE): Use them, add an argument.
(syntax_prefix_flag_p): New function.
(Fstring_to_syntax): Understand new "c" flag.
(Finternal_describe_syntax_value): Recognize new flag; use the
SYNTAX_FLAGS_* macros.
(scan_sexps_forward, Fparse_partial_sexp): Change representation of
comment style to accomodate the new styles.
(back_comment, forw_comment, Fforward_comment, scan_lists)
(scan_sexps_forward): Update code to obey the new comment style flag.
* src/syntax.h: Move SYNTAX_FLAGS_FOO() macros to syntax.c.
* src/casefiddle.c (casify_region): Use the new syntax_prefix_flag_p.
* lisp/progmodes/octave-mod.el (octave-mode-syntax-table): Use the new "c"
comment style.
* lisp/progmodes/scheme.el (scheme-mode-syntax-table):
* lisp/emacs-lisp/lisp-mode.el (lisp-mode-syntax-table): Remove spurious
"b" flag in "14b" syntax.

Fixes: debbugs:6834

1 files changed, 2 insertions, 49 deletions

diff --git a/src/syntax.h b/src/syntax.h
index 9eaf553f2e..48146572d1 100644
--- a/src/syntax.h
+++ b/src/syntax.h
@@ -128,56 +128,9 @@ extern Lisp_Object syntax_temp;
     : Qnil))
 #endif
 
-/* Then there are seven single-bit flags that have the following meanings:
-  1. This character is the first of a two-character comment-start sequence.
-  2. This character is the second of a two-character comment-start sequence.
-  3. This character is the first of a two-character comment-end sequence.
-  4. This character is the second of a two-character comment-end sequence.
-  5. This character is a prefix, for backward-prefix-chars.
-  6. see below
-  7. This character is part of a nestable comment sequence.
-  Note that any two-character sequence whose first character has flag 1
-  and whose second character has flag 2 will be interpreted as a comment start.
 
-  bit 6 is used to discriminate between two different comment styles.
-  Languages such as C++ allow two orthogonal syntax start/end pairs
-  and bit 6 is used to determine whether a comment-end or Scommentend
-  ends style a or b.  Comment start sequences can start style a or b.
-  Style a is always the default.
-  */
-
-/* These macros extract a particular flag for a given character.  */
-
-#define SYNTAX_COMSTART_FIRST(c) ((SYNTAX_WITH_FLAGS (c) >> 16) & 1)
-
-#define SYNTAX_COMSTART_SECOND(c) ((SYNTAX_WITH_FLAGS (c) >> 17) & 1)
-
-#define SYNTAX_COMEND_FIRST(c) ((SYNTAX_WITH_FLAGS (c) >> 18) & 1)
-
-#define SYNTAX_COMEND_SECOND(c) ((SYNTAX_WITH_FLAGS (c) >> 19) & 1)
-
-#define SYNTAX_PREFIX(c) ((SYNTAX_WITH_FLAGS (c) >> 20) & 1)
-
-#define SYNTAX_COMMENT_STYLE(c) ((SYNTAX_WITH_FLAGS (c) >> 21) & 1)
-
-#define SYNTAX_COMMENT_NESTED(c) ((SYNTAX_WITH_FLAGS (c) >> 22) & 1)
-
-/* These macros extract specific flags from an integer
-   that holds the syntax code and the flags.  */
-
-#define SYNTAX_FLAGS_COMSTART_FIRST(flags) (((flags) >> 16) & 1)
-
-#define SYNTAX_FLAGS_COMSTART_SECOND(flags) (((flags) >> 17) & 1)
-
-#define SYNTAX_FLAGS_COMEND_FIRST(flags) (((flags) >> 18) & 1)
-
-#define SYNTAX_FLAGS_COMEND_SECOND(flags) (((flags) >> 19) & 1)
-
-#define SYNTAX_FLAGS_PREFIX(flags) (((flags) >> 20) & 1)
-
-#define SYNTAX_FLAGS_COMMENT_STYLE(flags) (((flags) >> 21) & 1)
-
-#define SYNTAX_FLAGS_COMMENT_NESTED(flags) (((flags) >> 22) & 1)
+/* Whether the syntax of the character C has the prefix flag set.  */
+extern int syntax_prefix_flag_p (int c);
 
 /* This array, indexed by a character, contains the syntax code which that
  character signifies (as a char).  For example,