Kevin Rodgers wrote:
> Matthew Flaschen wrote:
>> I am trying to figure out how to create a new function that will scroll
>> up a screen if possible, or go the beginning of the buffer otherwise; I
>> would then bind this to M-v.  Ultimately, I want to have the corollary
>> behavior for C-v.
>>
>> I can't figure out how to test whether it is possible to scroll up/down
>> an entire screen.  I found (goto-char (point-min/max)) , so that part
>> should be okay.
> 
> (if (pos-visible-in-window-p (point-min))
>     (beginning-of-buffer)
>   (scroll-down))
> 

Thanks, that was what I needed.  I ended up with:

(defun power-top ()
"Scrolls up a screen if possible, or goes to the top of the buffer"
(interactive)
(if (pos-visible-in-window-p (point-min))
    (goto-char (point-min))
  (scroll-down)))

(defun power-bottom ()
"Scrolls up a screen if possible, or goes to the top of the buffer"
(interactive)
(if (pos-visible-in-window-p (point-max))
    (goto-char (point-max))
  (scroll-up)))

(global-set-key [?\M-v] 'power-top )
(global-set-key [?\C-v] 'power-bottom )