Re: display-buffer cleverness - how to tame?

[martin rudalics <rudalics@gmx.at>]

 > So the question is, then, how to get Emacs 23 to not split that (non-full-width
 > largest) window if it is not the lru window?

Exact.

 > However, the doc string for `split-window-preferred-function' is not clear (to
 > me). First, this sentence is not grammatically correct; I can't understand it:
 >
 > "If non-nil, a function called with a window as single argument
 > supposed to split that window and return the new window."
 >
 > That seems to say that the window argument is supposed to split itself, or
 > something like that.

Well, even an Emacs window won't split itself, but this part must be
rewritten anyway.

 >>From your description above, the function decides, based on a window passed as
 > arg, which window to split, and then splits the window it chooses. Is that
 > correct?

The function should split the window passed as arg but no one will ask
whether it really split that window.  As a matter of fact, the function
may do anything it wants as long as it returns a live window.

 > Why is a particular window passed as arg, if the choice of which window to split
 > is up to the function?

Because the standard (not user-written) functions will try to split the
window passed as arg.

 > Is there some usual interpretation/use of that window
 > arg?

The interpretation is "this is one of the windows Emacs 22 tried to split".

 > When `display-buffer' calls `split-window-preferred-function', which window
 > does it pass as arg?

In a first call the largest window of the selected frame, in the second
call the least recently used one.

 > What is the role/meaning of that window; how does
 > `display-buffer' pick it? You say the function is called "with the window to
 > split", but what does that mean, if it is the function itself that decides which
 > window to split (and splits it)?

Up to Emacs 22 the identity of the window to split was hardcoded.  The
present code gives you a way to override that while keeping most of the
historic details.  I dislike the get-largest/LRU-window mumbo jumbo and
rather have `split-window-preferred-function' decide which window(s) to
split ...

martin