bug#9350: 23.3; File menu should contain "split window horizontally C-x 3"

[martin rudalics]

>> I'd eventually want to rename `split-window' to `new-window' or
>> `make-new-window' and give it a fourth argument - the buffer to show in
>> the new window.
>
> But then the name doesn't make it clear that you're splitting an
> existing window.  I.e. it's moving towards display-buffer.

It would become more like `make-frame'.  But I'm not sure whether we
want or need that "splitting" connotation at all.  Most callers care
about one thing only: Get a new window to peruse.

> PS: One thing that annoys me in the current working of split-window: it
> doesn't let you say which window (the top or the bottom) is the new one.

The new one is that returned by `split-window', as before.

> This was fine back when windows had very little state of their own, but
> now it is important when it matters because of window-parameters,
> window-dedicated-p, ...
> So if we want to improve split-window, I think we should consider this
> issue as well.

Do you mean you need the identity of the new window when `split-window'
is called indirectly by another function?  Maybe you could provide a use
case?

martin