Re: help-window-select and info-lookup-symbol

[Helmut Eller <eller.helmut@gmail.com>]

* martin rudalics [2009-07-20 11:32+0200] writes:

> Restoring an old window configuration is awfully tricky.  Let W1 denote
> the window configuration before invoking help, W2 the configuration
> after invoking help (and after any `fit-window-to-buffer' and balancing
> stuff), and W3 the configuration when you press `q'.  A brute force
> approach (currently used by info or backtrace) simply restores W1 whe
> you press `q' which all so often drives me mad because it destroys the
> windows and window-buffer associations I have created in between.

For the debugger it's IMO the best option.

> Now theoretically, I could restore W1 if and only if the configurations
> W2 and W3 are equal.  In practice, however, this approach often failed
> here.  Hence, I tried to base the comparison on a weaker predicate of
> equality which ignored the identities of buffers displayed in other
> windows and the relative sizes of windows.  I got it to work for help
> buffers but was not able to make it work realiably with info buffers.

Comparing W2 and W3 per compare-window-configurations would probably
work as a start, but point should probably not be restored.

Here's the code that we use currently:

(defun slime-close-popup-window ()
  (when slime-popup-restore-data
    (destructuring-bind (popup-window selected-window old-buffer)
        slime-popup-restore-data
      (bury-buffer)
      (when (eq popup-window (selected-window))
        (cond ((and (not old-buffer) (not (one-window-p)))
               (delete-window popup-window))
              ((and old-buffer (buffer-live-p old-buffer))
               (set-window-buffer popup-window old-buffer))))
      (when (window-live-p selected-window)
        (select-window selected-window)))
    (kill-local-variable 'slime-popup-restore-data)))

popup-window is the window that displays the help content at W2.
selected-window was selected at W1.
old-buffer was the buffer associated with popup-window at W1.

It's far from perfect and it was a PITA to write.

Helmut.