Re: ruler support in hexl mode

[Masatake YAMATO]

> > +(defcustom hexl-follow-line t
> > +  "If non-nil then highlight the line address corresponding to point."
> > +  :type 'boolean
> > +  :group 'hexl)
> 
> Any reason why you do not simply use hl-line-mode ?
> Or, better yet, let the user select hl-line-mode if he wants it?

Using hl-line-mode is good idea. However, hl-line-mode hides the
highlighted character associated with the point in ascii area. I will
put other face than highlight on the character associated with the
point.

> > +;; This function is derived from `ruler-mode-ruler' in ruler-mode.el.
> > +(defun hexl-mode-ruler ()
> > +  "Return a string ruler for hexl mode."
> > +  (when hexl-use-ruler
> > +    (let* ((fullw (ruler-mode-full-window-width))
> > +      (w     (window-width))
> > +      (m     (window-margins))
> > +      (lsb   (ruler-mode-left-scroll-bar-cols))
> > +      (lf    (ruler-mode-left-fringe-cols))
> > +      (lm    (or (car m) 0))
> > +      (ruler (make-string fullw ?\ ))
> 
> We really need to move this out of ruler-mode into frame.el or some other
> "global" file.  And to give it a clean interface so its implementation can
> be improved later.

Are You talking about each functions or generic ruler mechanism?

About former, I have inspect ruler-mode.el again.

    (let* ((w     (window-width))
           (m     (window-margins))
           (lsb   (ruler-mode-left-scroll-bar-cols))
           (lf    (ruler-mode-left-fringe-cols t))
           (lm    (or (car m) 0))
           (rsb   (ruler-mode-right-scroll-bar-cols))
           (rf    (ruler-mode-right-fringe-cols t))
           (rm    (or (cdr m) 0))
           (ruler (make-string w ruler-mode-basic-graduation-char))
           (i     0)
           (j     (window-hscroll))
           k c l1 l2 r2 r1 h1 h2 f1 f2)

Next two functions should be in "global" file:
ruler-mode-left-scroll-bar-cols and ruler-mode-left-fringe-cols.
I think these should be renamed to  scroll-bar-columns and 
fringe-columns. How do you think?

> > +      (o     (+ lsb lf lm))
> > +      (x o)
> > +      (highlight (mod (hexl-current-address) 16)))
> > +      ;; "87654321"
> > +      (do ((i 8 (1- i)))
> > +     ((= i 0))
> > +   (aset ruler x (aref (number-to-string i) 0))
> > +   (setq x (1+ x)))
> > +      ;; "87654321  "
> > +      (setq x (+ x 2))                     ; ": "
> > +      ;; "87654321  0011 2233 4455 6677 8899 aabb ccdd eeff"
> > +      (do* ((i 0 (1+ i))
> > +       (c (format "%x" i) (format "%x" i)))
> > +     ((= i 16))
> > +   (aset ruler x (aref c 0))
> > +   (setq x (1+ x))
> > +   (aset ruler x (aref c 0))
> > +   (setq x (1+ x))
> > +   (if (= highlight i)
> > +       (put-text-property (- x 2) x 
> > +                          'face 'highlight
> > +                          ruler))
> > +   (when (= (mod i 2) 1) 
> > +     (aset ruler x ?\ )
> > +     (setq x (1+ x))))
> > +      ;; "87654321  0011 2233 4455 6677 8899 aabb ccdd eeff "
> > +      (setq x (1+ x))                      ; " "
> > +      ;; "87654321  0011 2233 4455 6677 8899 aabb ccdd eeff  
> > 0123456789abcdef"
> > +      (do* ((i 0 (1+ i))
> > +       (c (format "%x" i) (format "%x" i)))
> > +     ((= i 16))
> > +   (aset ruler x (aref c 0))
> > +   (setq x (1+ x))
> > +   (if (= highlight i)
> > +       (put-text-property (1- x) x 
> > +                          'face 'highlight
> > +                          ruler)))
> > +      ruler)))
> 
> Isn't this always building the exact same string, except for the size
> (which really does not need to depend on the window's width), the leading
> space (to align it), and the highlighting of the current column?
> 
> Couldn't we just do (100% untested code, inspired from buff-menu.el):
...

After modifying a bit, your code works fine.

Masatake YAMATO