Re: Tabbed buffers

[Stephen J. Turnbull]

Nick Roberts writes:

 > If I do C-x C-f *.c in XEmacs I only get one empty buffer called *.c
 > (21.4 (patch 19) "Constant Variable" XEmacs Lucid)

Oh.  I guess globbing in C-x C-f was added in the 21.5 series.  Sorry.
Then do it by hand.  Then do some Makefiles and the like.  Notice what
tabs appear according to the current buffer.

This behavior is highly configurable; filter-on-mode is just the
default (and only built-in) behavior.

 >  > C-h a buffers-tab will tell you a list of functions and variables used
 >  > to implement the default configuration.
 > 
 > There appear to be no functions that put a file/display a buffer in
 > a new tab, delete a tab etc.

Nope.  That's not how they're used.  That could be done, but it wasnt.

 > Also, unlike Eclipse there is just one gutter per frame, which
 > appears to be shared by all the buffers in that frame, just
 > displaying the tabs for the one selected.

In the default configuration, yes.

 > When a tab is selected it moves to the left, not just to the front.

Actually, that should not happen if you use the GUI (ie, click on the
tab).  (Or maybe that too is a bug fixed in 21.5.)  That is an
artifact of the underlying implementation which recomputes the tabs
each time the buffer displayed changes via switch-to-buffer.

 > They don't appear to be part of a toolkit but built from one.  Now
 > that toolkits like GTK provide tabs as widgets, I presume they
 > might be easier to add to Emacs.

That depends on whether you insist that they be cross-platform or not.
Native GTK widgets and native Windose widgets (not that they deserve
the name, as I understand it) require quite different kinds of TLC,
which conflict is an unending source of bugs if you try to provide a
flexible implementation with Lisp callbacks that works on both
platforms.  At least, that is our experience.