Local tool-bar (for one frame), [toggle-frame-toolbar]

[David Reitter]

Would people be interested in a change that introduces a function  
`tool-bar-toggle' (in toolbar.el), allowing to switch a tool-bar on  
and off in a single frame?
As shown below, it's not a minor mode (opposed to what Drew Adams  
suggested here:  http://lists.gnu.org/archive/html/emacs-devel/ 
2004-10/msg00248.html )

Also, I have implemented a little change that binds this to the tool- 
bar window button which exists on Mac OS X. The button click is bound  
to an event defined in keyboard.c (right now only in OS X), which  
gets mapped to [toggle-frame-toolbar] (in macterm.c). Then you do a  
simple

(global-set-key [toggle-frame-toolbar] 'tool-bar-toggle)




;; local toolbars

(defun tool-bar-enabled-p (&optional frame)
"Evaluates to non-nil if the tool-bar is present
in frame FRAME. If FRAME is nil, the function applies
to the selected frame."
  (> (or (frame-parameter frame 'tool-bar-lines) 0) 0))

(defun tool-bar-toggle (&optional frame)
"Switches the tool bar on and off in frame FRAME.
If FRAME is nil, the change applies to the selected frame."
(interactive)
  (modify-frame-parameters frame
   (list (cons 'tool-bar-lines
           (if (tool-bar-enabled-p)
           0
         1
         )))))