Merge syntax-propertize--done and parse-sexp-propertize-done

* lisp/emacs-lisp/syntax.el (syntax-propertize--done): Remove.
(syntax-propertize): Set syntax-propertize--done even if
syntax-propertize-function is nil.  Avoid recursive invocations.
(syntax-propertize-chunks): New var.
(internal--syntax-propertize): Use it.  Rename from syntax--jit-propertize.
Simplify.
(parse-sexp-propertize-function): Don't set any more.

* src/syntax.c (SETUP_SYNTAX_TABLE): Call parse_sexp_propertize as needed.
(parse_sexp_propertize): Don't assume charpos is not yet propertized.
Call Qinternal__syntax_propertize instead of
Vparse_sexp_propertize_function.  Truncate e_property if needed.
(update_syntax_table_forward): Streamline.
(syms_of_syntax): Define Qinternal__syntax_propertize.
(syntax_propertize__done): Rename from parse_sexp_propertize_done.

2 files changed, 60 insertions, 58 deletions

diff --git a/src/syntax.c b/src/syntax.c
index fcd6d017d33..de45c50ca3f 100644
--- a/src/syntax.c
+++ b/src/syntax.c
@@ -181,6 +181,7 @@ static void scan_sexps_forward (struct lisp_parse_state *,
                                 ptrdiff_t, ptrdiff_t, ptrdiff_t, EMACS_INT,
                                 bool, Lisp_Object, int);
 static bool in_classes (int, Lisp_Object);
+static void parse_sexp_propertize (ptrdiff_t charpos);
 
 /* This setter is used only in this file, so it can be private.  */
 static void
@@ -247,12 +248,12 @@ SETUP_SYNTAX_TABLE (ptrdiff_t from, ptrdiff_t count)
   gl_state.offset = 0;
   if (parse_sexp_lookup_properties)
     {
-      if (count > 0 || from > BEGV)
-        update_syntax_table (count > 0 ? from : from - 1, count, true, Qnil);
-      if (gl_state.e_property > parse_sexp_propertize_done)
+      if (count > 0)
+        update_syntax_table_forward (from, true, Qnil);
+      else if (from > BEGV)
         {
-          gl_state.e_property = parse_sexp_propertize_done;
-          gl_state.e_property_truncated = true;
+          update_syntax_table (from - 1, count, true, Qnil);
+          parse_sexp_propertize (from - 1);
         }
     }
 }
@@ -478,33 +479,44 @@ update_syntax_table (ptrdiff_t charpos, EMACS_INT count, bool init,
 static void
 parse_sexp_propertize (ptrdiff_t charpos)
 {
-  EMACS_INT modiffs = CHARS_MODIFF;
-  safe_call1 (Vparse_sexp_propertize_function,
-              make_number (1 + charpos));
-  if (modiffs != CHARS_MODIFF)
-    error ("parse-sexp-propertize-function modified the buffer!");
-  if (parse_sexp_propertize_done <= charpos)
-    error ("parse-sexp-propertize-function did not move"
-           " parse-sexp-propertize-done");
-  SETUP_SYNTAX_TABLE (charpos, 1);
+  EMACS_INT zv = ZV;
+  if (syntax_propertize__done <= charpos
+      && syntax_propertize__done < zv)
+    {
+      EMACS_INT modiffs = CHARS_MODIFF;
+      safe_call1 (Qinternal__syntax_propertize,
+                  make_number (min (zv, 1 + charpos)));
+      if (modiffs != CHARS_MODIFF)
+        error ("parse-sexp-propertize-function modified the buffer!");
+      if (syntax_propertize__done <= charpos
+          && syntax_propertize__done < zv)
+        error ("parse-sexp-propertize-function did not move"
+               " syntax-propertize--done");
+      SETUP_SYNTAX_TABLE (charpos, 1);
+    }
+  else if (gl_state.e_property > syntax_propertize__done)
+    {
+      gl_state.e_property = syntax_propertize__done;
+      gl_state.e_property_truncated = true;
+    }
 }
 
 void
 update_syntax_table_forward (ptrdiff_t charpos, bool init,
-                     Lisp_Object object)
+                             Lisp_Object object)
 {
-  if (!(gl_state.e_property_truncated))
-    update_syntax_table (charpos, 1, init, object);
-  if ((gl_state.e_property > parse_sexp_propertize_done
-       || gl_state.e_property_truncated)
-      && NILP (object))
+  if (gl_state.e_property_truncated)
     {
-      if (parse_sexp_propertize_done > charpos)
-        {
-          gl_state.e_property = parse_sexp_propertize_done;
-          gl_state.e_property_truncated = true;
-        }
-      else
+      eassert (NILP (object));
+      eassert (charpos >= gl_state.e_property);
+      eassert (charpos >= syntax_propertize__done);
+      parse_sexp_propertize (charpos);
+    }
+  else
+    {
+      update_syntax_table (charpos, 1, init, object);
+      if (gl_state.e_property > syntax_propertize__done
+          && NILP (object))
         parse_sexp_propertize (charpos);
     }
 }
@@ -2332,13 +2344,13 @@ forw_comment (ptrdiff_t from, ptrdiff_t from_byte, ptrdiff_t stop,
           && SYNTAX_FLAGS_COMMENT_STYLE (syntax, 0) == style
           && (SYNTAX_FLAGS_COMMENT_NESTED (syntax) ?
               (nesting > 0 && --nesting == 0) : nesting < 0))
-        /* we have encountered a comment end of the same style
+        /* We have encountered a comment end of the same style
            as the comment sequence which began this comment
-           section */
+           section.  */
         break;
       if (code == Scomment_fence
           && style == ST_COMMENT_STYLE)
-        /* we have encountered a comment end of the same style
+        /* We have encountered a comment end of the same style
            as the comment sequence which began this comment
            section.  */
         break;
@@ -2346,8 +2358,8 @@ forw_comment (ptrdiff_t from, ptrdiff_t from_byte, ptrdiff_t stop,
           && code == Scomment
           && SYNTAX_FLAGS_COMMENT_NESTED (syntax)
           && SYNTAX_FLAGS_COMMENT_STYLE (syntax, 0) == style)
-        /* we have encountered a nested comment of the same style
-           as the comment sequence which began this comment section */
+        /* We have encountered a nested comment of the same style
+           as the comment sequence which began this comment section.  */
         nesting++;
       INC_BOTH (from, from_byte);
       UPDATE_SYNTAX_TABLE_FORWARD (from);
@@ -2363,9 +2375,8 @@ forw_comment (ptrdiff_t from, ptrdiff_t from_byte, ptrdiff_t stop,
               ? nesting > 0 : nesting < 0))
         {
           if (--nesting <= 0)
-            /* we have encountered a comment end of the same style
-               as the comment sequence which began this comment
-               section */
+            /* We have encountered a comment end of the same style
+               as the comment sequence which began this comment section.  */
             break;
           else
             {
@@ -2382,9 +2393,8 @@ forw_comment (ptrdiff_t from, ptrdiff_t from_byte, ptrdiff_t stop,
               && SYNTAX_FLAGS_COMSTART_SECOND (other_syntax))
           && (SYNTAX_FLAGS_COMMENT_NESTED (syntax) ||
               SYNTAX_FLAGS_COMMENT_NESTED (other_syntax)))
-        /* we have encountered a nested comment of the same style
-           as the comment sequence which began this comment
-           section */
+        /* We have encountered a nested comment of the same style
+           as the comment sequence which began this comment section.  */
         {
           INC_BOTH (from, from_byte);
           UPDATE_SYNTAX_TABLE_FORWARD (from);
@@ -2628,9 +2638,9 @@ scan_lists (EMACS_INT from, EMACS_INT count, EMACS_INT depth, bool sexpflag)
   bool quoted;
   bool mathexit = 0;
   enum syntaxcode code;
-  EMACS_INT min_depth = depth;    /* Err out if depth gets less than this.  */
-  int comstyle = 0;         /* style of comment encountered */
-  bool comnested = 0;       /* whether the comment is nestable or not */
+  EMACS_INT min_depth = depth;  /* Err out if depth gets less than this.  */
+  int comstyle = 0;             /* Style of comment encountered.  */
+  bool comnested = 0;           /* Whether the comment is nestable or not.  */
   ptrdiff_t temp_pos;
   EMACS_INT last_good = from;
   bool found;
@@ -2674,11 +2684,11 @@ scan_lists (EMACS_INT from, EMACS_INT count, EMACS_INT depth, bool sexpflag)
                   SYNTAX_FLAGS_COMSTART_SECOND (other_syntax))
               && parse_sexp_ignore_comments)
             {
-              /* we have encountered a comment start sequence and we
+              /* We have encountered a comment start sequence and we
                  are ignoring all text inside comments.  We must record
                  the comment style this sequence begins so that later,
                  only a comment end of the same style actually ends
-                 the comment section */
+                 the comment section.  */
               code = Scomment;
               comstyle = SYNTAX_FLAGS_COMMENT_STYLE (other_syntax, syntax);
               comnested |= SYNTAX_FLAGS_COMMENT_NESTED (other_syntax);
@@ -2696,7 +2706,7 @@ scan_lists (EMACS_INT from, EMACS_INT count, EMACS_INT depth, bool sexpflag)
               if (from == stop)
                 goto lose;
               INC_BOTH (from, from_byte);
-              /* treat following character as a word constituent */
+              /* Treat following character as a word constituent.  */
             case Sword:
             case Ssymbol:
               if (depth || !sexpflag) break;
@@ -3501,7 +3511,7 @@ Sixth arg COMMENTSTOP non-nil means stop at the start of a comment.
       target = XINT (targetdepth);
     }
   else
-    target = TYPE_MINIMUM (EMACS_INT);  /* We won't reach this depth */
+    target = TYPE_MINIMUM (EMACS_INT);  /* We won't reach this depth.  */
 
   validate_region (&from, &to);
   scan_sexps_forward (&state, XINT (from), CHAR_TO_BYTE (XINT (from)),
@@ -3650,19 +3660,10 @@ Otherwise, that text property is simply ignored.
 See the info node `(elisp)Syntax Properties' for a description of the
 `syntax-table' property.  */);
 
-  DEFVAR_INT ("parse-sexp-propertize-done", parse_sexp_propertize_done,
+  DEFVAR_INT ("syntax-propertize--done", syntax_propertize__done,
               doc: /* Position up to which syntax-table properties have been set.  */);
-  parse_sexp_propertize_done = -1;
-
-  DEFVAR_LISP ("parse-sexp-propertize-function",
-               Vparse_sexp_propertize_function,
-          doc: /* Function to set the `syntax-table' text property.
-Called with one argument, the position at which the property is needed.
-After running it, `parse-sexp-propertize-done' should be strictly greater
-than the argument passed.  */);
-  /* Note: Qnil is a temporary (and invalid) value; it will be properly set in
-     syntax.el.  */
-  Vparse_sexp_propertize_function = Qnil;
+  syntax_propertize__done = -1;
+  DEFSYM (Qinternal__syntax_propertize, "internal--syntax-propertize");
 
   words_include_escapes = 0;
   DEFVAR_BOOL ("words-include-escapes", words_include_escapes,
diff --git a/src/syntax.h b/src/syntax.h
index 9c44181155f..34b652ba9c8 100644
--- a/src/syntax.h
+++ b/src/syntax.h
@@ -174,9 +174,10 @@ SYNTAX_TABLE_BYTE_TO_CHAR (ptrdiff_t bytepos)
 
 INLINE void
 UPDATE_SYNTAX_TABLE_FORWARD (ptrdiff_t charpos)
-{
+{ /* Performs just-in-time syntax-propertization.  */
   if (parse_sexp_lookup_properties && charpos >= gl_state.e_property)
-    update_syntax_table_forward (charpos + gl_state.offset, false, gl_state.object);
+    update_syntax_table_forward (charpos + gl_state.offset,
+                                 false, gl_state.object);
 }
 
 /* Make syntax table state (gl_state) good for CHARPOS, assuming it is