*: replace the "shelf" with "contexts"

This is unfortunately a bit of a large commit, but it's at least
pretty much all on-topic for the generalized "contexts" feature.

Rather than waste time trying to split this further into smaller
commits, I'm just landing it as-is, now that I've lived with the
interaction model long enough to not completely hate it.

I fully expect to revisit this in the future.  One TODO item in
particular I'd like to note is "sending" windows to contexts
always creates a new virtual desktop for the sent window in the
destination context.  What should really happen is the
destination context should be checked for an empty desktop, and a
new desktop created only when there isn't an empty one to be
reused for receiving the sent window.  Note this only affects
non-migrate sends, as migrates (modified by Shift) explicitly use
the existing focused desktop at the destination context.

See the README for more information on how contexts work and
what's different about the interaction model.  It's fairly
minimal, most of what you already know how to do should keep
working as-is.  The only oddity would be Mos1-s no longer
"shelves" windows, it's now a modifier to turn "migrates" into
"sends", and by itself is a noop now.

Colors used for contexts haven't been refined and are enumerated
in src/context_colors.def.

1 files changed, 3 insertions, 1 deletions

diff --git a/src/desktop.h b/src/desktop.h
index 1503407..597adb8 100644
--- a/src/desktop.h
+++ b/src/desktop.h
@@ -7,16 +7,18 @@
 
 typedef struct _vwm_t vwm_t;
 typedef struct _vwm_window_t vwm_window_t;
+typedef struct _vwm_context_t vwm_context_t;
 
 typedef struct _vwm_desktop_t {
 	list_head_t	desktops;		/* global list of (virtual) desktops */
 	list_head_t	desktops_mru;		/* global list of (virtual) desktops in MRU order */
+	vwm_context_t	*context;		/* context this desktop belongs to */
 	vwm_window_t	*focused_window;	/* the focused window on this virtual desktop */
 } vwm_desktop_t;
 
 vwm_desktop_t * vwm_desktop_mru(vwm_t *vwm, vwm_desktop_t *desktop);
 int vwm_desktop_focus(vwm_t *vwm, vwm_desktop_t *desktop);
-vwm_desktop_t * vwm_desktop_create(vwm_t *vwm);
+vwm_desktop_t * vwm_desktop_create(vwm_t *vwm, vwm_context_t *context);
 void vwm_desktop_destroy(vwm_t *vwm, vwm_desktop_t *desktop);
 vwm_desktop_t * vwm_desktop_next_mru(vwm_t *vwm, vwm_desktop_t *desktop, vwm_direction_t direction);
 vwm_desktop_t * vwm_desktop_next(vwm_t *vwm, vwm_desktop_t *desktop, vwm_direction_t direction);