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

[martin rudalics <rudalics@gmx.at>]

 >> IIUC in that case a `display-buffer' following another would wipe out
 >> the variable set by the former.  The problem is with recognizing whether
 >> the buffer `display-buffer' is going to replace in some window was a
 >> buffer the user switched to "manually" or "automatically".  In the
 >> former case `display-buffer' should remember the buffer in its
 >> `old-buffer' variable while in the latter it should leave that variable
 >> alone.  Currently `display-buffer' has no means to distinguish these
 >> cases.
 >
 > I was thinking that a new function or macro would delete the
 > buffer-local variable before displaying the buffer, something like
 > with-help-window.  display-buffer would be called in the process but
 > display-buffer would know nothing about the buffer-local variable.

The functions that could safely decide whether a buffer-local-variable
shall be deleted is the "any function calling `display-buffer' but the
help/info type ones".  It's impossible to enumerate them all because
someone might add a new one tomorrow.

What could be done is provide a variable `do-not-wipe-out-old-value'
which is normally nil but the help/info type functions bind to t around
their `display-buffer' calls.  And `display-buffer' wouldn't wipe out
the old value if that variable is t.

martin