Re: C++ mode and c-beginning-of-current-token

[martin rudalics]

> I do have my own problems with UPDATE_SYNTAX_TABLE_BACKWARD.  To
> reproduce with Emacs -Q define foo as
>
> (defun foo ()
>   (interactive)
>   (put-text-property (1- (point)) (point) 'syntax-table '(2))
>   (setq parse-sexp-lookup-properties t))
>
> open a text-mode buffer, insert a couple of non-word chars in the
> buffer, leave point after them, and type M-x foo followed by M-b.  On my
> system it goes back by _two_ characters instead of one.  I'm yet too
> silly to understand what's going on.

The attached patch seems to fix both the syntax and word backward scanning
problems.  Could someone please try?

*** syntax.c    Wed Jan 17 09:31:10 2007
--- syntax.c    Thu May 17 23:30:50 2007
***************
*** 1276,1294 ****
           position of it.  */
        while (1)
        {
-         int temp_byte;
- 
          if (from == beg)
            break;
!         temp_byte = dec_bytepos (from_byte);
          UPDATE_SYNTAX_TABLE_BACKWARD (from);
!         ch0 = FETCH_CHAR (temp_byte);
          code = SYNTAX (ch0);
          if (!(words_include_escapes
                && (code == Sescape || code == Scharquote)))
            if (code != Sword || WORD_BOUNDARY_P (ch0, ch1))
!             break;
!         DEC_BOTH (from, from_byte);
          ch1 = ch0;
        }
        count++;
--- 1276,1294 ----
           position of it.  */
        while (1)
        {
          if (from == beg)
            break;
!         DEC_BOTH (from, from_byte);
          UPDATE_SYNTAX_TABLE_BACKWARD (from);
!         ch0 = FETCH_CHAR (from_byte);
          code = SYNTAX (ch0);
          if (!(words_include_escapes
                && (code == Sescape || code == Scharquote)))
            if (code != Sword || WORD_BOUNDARY_P (ch0, ch1))
!             {
!               INC_BOTH (from, from_byte);
!               break;
!             }
          ch1 = ch0;
        }
        count++;
***************
*** 1669,1678 ****
                      p = GPT_ADDR;
                      stop = endp;
                    }
-                 if (! fastmap[(int) SYNTAX (p[-1])])
-                   break;
                  p--, pos--;
!                 UPDATE_SYNTAX_TABLE_BACKWARD (pos - 1);
                }
          }
        }
--- 1669,1681 ----
                      p = GPT_ADDR;
                      stop = endp;
                    }
                  p--, pos--;
!                 UPDATE_SYNTAX_TABLE_BACKWARD (pos);
!                 if (! fastmap[(int) SYNTAX (*p)])
!                   {
!                     p++, pos++;
!                     break;
!                   }
                }
          }
        }