Some parts of font locking in my new major mode works only after modifying the buffer

Some parts of font locking in my new major mode works only after modifying the buffer

[mathias.dahl]

Hi,

I see a strange fenomen with my new major mode. I have only two keyword regexps (see below). If I load a file that uses this major mode (or runs the major mode again, or calls font-lock-fontify-buffer manually), the first part of the first non-empty line after a comment line, does not get coloured. The rest of the text is correctly colored. What's more, if I modify the buffer, either the line that has missing colours, or a line before it (I can insert a space, and then delete it), suddenly the missing color is added. I have tried to understand if there is anything wrong with the regexps but since they work on all other lines, I cannot understand how they would be wrong.

Here is some example buffer content:

1 <editword> <n> Words = {Esc} $2 $1;
2 
3 ### Lines
4
5 New Line = {Enter};
6 Newline Indent = {Ctrl+j};

(line numbers are added here, by me)

Above, "New Line" on line 5 is not coloured with font-lock-variable-name-face like it should, but "Newline Indent" on line 6 does. And, again, if I touch the buffer before line 5, it suddenly works, even if I later undo that change.

Here is the code:

(defvar vocola-mode-syntax-table
  (let ((st (make-syntax-table)))
    (modify-syntax-entry ?# "<" st)
    (modify-syntax-entry ?\n ">" st)
    (modify-syntax-entry ?\{ "(" st)
    (modify-syntax-entry ?\} ")" st)
    st)
  "Syntax table used while in `vocola-mode'.")

(defvar vocola-font-lock-keywords
  '(("^\\([^=]+\\)=" 1 font-lock-variable-name-face)
    ("{\\(.+?\\)}" 1 font-lock-type-face)))

(defvar vocola-font-lock-defaults
  '(vocola-font-lock-keywords
    nil nil))

;;;###autoload
(define-derived-mode vocola-mode prog-mode "Vocola"
  "Major mode for editing Vocola speech macro files"
  (set (make-local-variable 'font-lock-defaults) vocola-font-lock-defaults)  
  (abbrev-mode 1))

(See http://paste.lisp.org/+2YVF for a colorful version)

Any ideas?

Thanks!

/Mathias

Re: Some parts of font locking in my new major mode works only after modifying the buffer

[Stefan Monnier]

> 1 <editword> <n> Words = {Esc} $2 $1;
> 2 
> 3 ### Lines
> 4
> 5 New Line = {Enter};
> 6 Newline Indent = {Ctrl+j};
[...]
>   '(("^\\([^=]+\\)=" 1 font-lock-variable-name-face)

This regexp will match (on the first call) "<editword> <n> Words =" on
the first call.  And on the second it will match:

" {Esc} $2 $1;

### Lines
New Line ="

This text includes parts that are already highlighted (the "### Lines"
comment), so font-lock doesn't apply the text-property.  You can force
it to apply the text property (using the OVERRIDE part of the rule, see
C-h v font-lock-keywords), but I doubt that's what you want anyway,


        Stefan