Re: Advice on troubleshooting function to "unscroll"

[Will Monroe]

Joost,

Thank you for you response!

On 01/25/2015 03:35 PM, Joost Kremers wrote:
> Will Monroe wrote:
> > (defadvice scroll-up (before remember-for-unscroll
> >                              activate compile)
> >     "Remember where we started from, for 'unscroll'."
> >     (if (not (eq last-command 'scroll-up))
>
> Note that
>
>      (if (not <some-test>)
>           ... )
>
> can be written as
>
>      (unless <some-test>
>        ...)
>
> if you don't have an `else' part. It's slightly more readable that way
> IMHO.

Thanks for recommending that more-readable rewrite.  I will look into 
redrafting it this way.

> Also, as of (I think) Emacs 24.4, defadvice is no longer the recommended
> way to advise functions. There's a new package (`nadvice.el`) that
> defines `advice-add`. See the Elisp manual, section "Advising functions".
>
> [...]

Thank you again.  This is also very helpful.  I found that defadvice 
still worked for this example (with one change, see below) but I won't 
likely use it again since it's no longer preferred.

> > The test was just opening a lengthy file, usually an info page or an
> > existing org-mode file, pressing C-v a few times, and then using M-x
> > unscroll.  In all cases, I found that M-x unscroll would return to the
> > position just before the last C-v but not to the original position.  In
> > other words, if I pressed C-v two times and then pressed M-x unscroll,
> > in would only go back one C-v.  My intent, and that of the example in
> > the book, is to return the point the position before any C-v key
> > sequences were pressed.
>
> Have you checked what `C-v` is bound to? In my Emacs (24.4) it's bound
> to `scroll-up-command`, not to `scroll-up`. So that would defeat your if
> test above.

So simple!  Thank you for this insight.  Going forward, I'll include a 
check of what functions my keybindings are actually bound to!  After 
substituting scroll-up-command for scroll-up in two places, it worked as 
intended.

Thank you very much,

Will

> HTH