diff --git a/README b/README
index a43c211..038fc9d 100644
--- a/README
+++ b/README
@@ -13,6 +13,14 @@ that can be performed through the GUI.
 Building
 --------
 
+Prerequisites:
+
+- flex
+- bison
+- fig2dev
+- ImageMagick
+- Gtk+ 2.x development package (libgtk2.0-dev or similar)
+
 Check out the repository:
 
   svn co http://svn.openmoko.org/trunk/eda/fped
@@ -79,7 +87,7 @@ The file has the following structure:
 
 frame definitions
 ...
-part name
+package name
 objects
 ...
 
@@ -234,18 +242,21 @@ b: vec @(1mm, 1mm)
 meas a b 0.2 mm
 
 
-Part name
-- - - - -
+Package name
+- - - - - -
 
-The part name is a string of alphanumerical characters. Underscores are
-allowed in the part name as well.
+The package name is a string of printable ASCII characters, including
+spaces.
 
-part "<name>"
+package "<name>"
 
 Examples:
 
-part "SSOP_48"
-part "0603"
+package "48-SSOP"
+package "0603"
+
+Like in pad names, variables are expanded in package names. This allows
+the generation of multiple packages from a single definition.
 
 
 Frames
diff --git a/TODO b/TODO
index 5039336..62c34b5 100644
--- a/TODO
+++ b/TODO
@@ -25,12 +25,19 @@ Style:
   excessively large.
 - pango_layout_get_size doesn't seem to consider rotation, so we currently
   don't properly size rotated text.
+- when changing the part, we should automatically switch to a configuration
+  that generates any of its (non-global) elements
 
 Bugs:
 - default silk width has no business being hard-coded in obj.c
 - undelete only works if not much has changed since the deletion
 - focus should return to canvas if nobody else wants it
 - whenever we call parse_* for input parsing, we may leak lots of expressions
+- can't edit measurement labels through the GUI
+- r of rpads is misleading, particularly if we have a circle
+- we can't enter an arc through the GUI / can't convert a circle to an arc
+- using variables in a measurement offset causes a crash because evaluation
+  takes place after all table entries have been visited
 
 Code cleanup:
 - merge edit_unique with edit_name
@@ -68,7 +75,4 @@ Future directions:
 - advanced: non-standard solder mask
 - advanced: solder paste exceptions (subtractive, additive)
 - advanced: silk line width
-- future: when encountering an error after a change, we could try to find the
-  same element in the old instance, and select it
 - future: consider editing non-canvas items in place
-- near future: treat part name as pattern
diff --git a/dump.c b/dump.c
index d5e981a..ef3576b 100644
--- a/dump.c
+++ b/dump.c
@@ -485,7 +485,7 @@ int dump(FILE *file)
 	fprintf(file, "/* MACHINE-GENERATED ! */\n\n");
 	for (frame = frames; frame; frame = frame->next) {
 		if (!frame->name) {
-			fprintf(file, "part \"%s\"\n", part_name);
+			fprintf(file, "package \"%s\"\n", pkg_name);
 			dump_frame(file, frame, "");
 		} else {
 			fprintf(file, "frame %s {\n", frame->name);
diff --git a/fpd.l b/fpd.l
index edfd6d0..5d6f200 100644
--- a/fpd.l
+++ b/fpd.l
@@ -89,7 +89,9 @@ SP	[\t ]*
 <INITIAL>"loop"			{ BEGIN(NOKEYWORD);
 				  return TOK_LOOP; }
 <INITIAL>"part"			{ BEGIN(NOKEYWORD);
-				  return TOK_PART; }
+				  return TOK_PACKAGE; }
+<INITIAL>"package"		{ BEGIN(NOKEYWORD);
+				  return TOK_PACKAGE; }
 <INITIAL>"frame"		{ BEGIN(NOKEYWORD);
 				  is_table = 0;
 				  return TOK_FRAME; }
diff --git a/fpd.y b/fpd.y
index 0464c9b..8648d4f 100644
--- a/fpd.y
+++ b/fpd.y
@@ -154,7 +154,7 @@ static struct obj *new_obj(enum obj_type type)
 
 
 %token		START_FPD START_EXPR START_VAR START_VALUES
-%token		TOK_SET TOK_LOOP TOK_PART TOK_FRAME TOK_TABLE TOK_VEC
+%token		TOK_SET TOK_LOOP TOK_PACKAGE TOK_FRAME TOK_TABLE TOK_VEC
 %token		TOK_PAD TOK_RPAD TOK_RECT TOK_LINE TOK_CIRC TOK_ARC
 %token		TOK_MEAS TOK_MEASX TOK_MEASY
 %token		TOK_NEXT TOK_NEXT_INVERTED TOK_MAX TOK_MAX_INVERTED
@@ -210,20 +210,20 @@ fpd:
 	;
 
 part_name:
-	TOK_PART STRING
+	TOK_PACKAGE STRING
 		{
 			const char *p;
 
 			if (!*$2) {
-				yyerrorf("invalid part name");
+				yyerrorf("invalid package name");
 				YYABORT;
 			}
 			for (p = $2; *p; *p++)
 				if (*p < 32 || *p > 126) {
-					yyerrorf("invalid part name");
+					yyerrorf("invalid package name");
 					YYABORT;
 				}
-			part_name = $2;
+			pkg_name = $2;
 		}
 	;
 
@@ -394,7 +394,6 @@ vec:
 			$$->y = $6;
 			$$->frame = curr_frame;
 			$$->next = NULL;
-			$$->samples = NULL;
 			last_vec = $$;
 			*next_vec = $$;
 			next_vec = &$$->next;
diff --git a/fped.c b/fped.c
index 79afb99..7c277bc 100644
--- a/fped.c
+++ b/fped.c
@@ -91,8 +91,8 @@ int main(int argc, char **argv)
 		usage(name);
 	}
 
-	if (!part_name)
-		part_name = stralloc("_");
+	if (!pkg_name)
+		pkg_name = stralloc("_");
 
 	reporter = report_to_stderr;
 	if (!instantiate())
diff --git a/gui_frame.c b/gui_frame.c
index a3c5175..a8a6d1d 100644
--- a/gui_frame.c
+++ b/gui_frame.c
@@ -1236,10 +1236,10 @@ static void dont_build_items(struct frame *frame)
 }
 
 
-/* ----- part name --------------------------------------------------------- */
+/* ----- package name ------------------------------------------------------ */
 
 
-static int validate_part_name(const char *s, void *ctx)
+static int validate_pkg_name(const char *s, void *ctx)
 {
 	if (!*s)
 		return 0;
@@ -1251,7 +1251,7 @@ static int validate_part_name(const char *s, void *ctx)
 	return 1;
 }
 
-static void unselect_part_name(void *data)
+static void unselect_pkg_name(void *data)
 {
 	GtkWidget *widget = data;
 
@@ -1259,40 +1259,107 @@ static void unselect_part_name(void *data)
 }
 
 
-static gboolean part_name_edit_event(GtkWidget *widget, GdkEventButton *event,
+static gboolean pkg_name_edit_event(GtkWidget *widget, GdkEventButton *event,
     gpointer data)
 {
 	switch (event->button) {
 	case 1:
-		inst_select_outside(widget, unselect_part_name);
+		inst_select_outside(widget, unselect_pkg_name);
 		label_in_box_bg(widget, COLOR_PART_NAME_EDITING);
-		status_set_type_entry("part =");
-		status_set_name("%s", part_name);
+		status_set_type_entry("package =");
+		status_set_name("%s", pkg_name);
 		edit_nothing();
-		edit_name(&part_name, validate_part_name, NULL);
+		edit_name(&pkg_name, validate_pkg_name, NULL);
 		break;
 	}
 	return TRUE;
 }
 
 
-static GtkWidget *build_part_name(void)
+static GtkWidget *build_pkg_name(void)
 {
 	GtkWidget *label;
 
-	label = label_in_box_new(part_name);
+	label = label_in_box_new(pkg_name);
 	gtk_misc_set_padding(GTK_MISC(label), 2, 2);
 	gtk_misc_set_alignment(GTK_MISC(label), 0, 0);
 
 	label_in_box_bg(label, COLOR_PART_NAME);
 
 	g_signal_connect(G_OBJECT(box_of_label(label)),
-	    "button_press_event", G_CALLBACK(part_name_edit_event), NULL);
+	    "button_press_event", G_CALLBACK(pkg_name_edit_event), NULL);
 
 	return box_of_label(label);
 }
 
 
+/* ----- packages ---------------------------------------------------------- */
+
+
+static gboolean pkg_scroll_event(GtkWidget *widget, GdkEventScroll *event,
+    gpointer data)
+{
+	struct pkg *pkg, *last;
+
+	switch (event->direction) {
+	case GDK_SCROLL_UP:
+		if (active_pkg->next)
+			active_pkg = active_pkg->next;
+		else
+			active_pkg = pkgs->next;
+		change_world();
+		break;
+	case GDK_SCROLL_DOWN:
+		last = NULL;
+		for (pkg = pkgs->next; pkg && (!last || pkg != active_pkg);
+		    pkg = pkg->next)
+			last = pkg;
+		active_pkg = last;
+		change_world();
+		break;
+	default:
+		/* ignore */;
+	}
+	return TRUE;
+}
+
+
+static gboolean pkg_select_event(GtkWidget *widget, GdkEventButton *event,
+    gpointer data)
+{
+	struct pkg *pkg = data;
+
+	switch (event->button) {
+	case 1:
+		active_pkg = pkg;
+		/* @@@ we could actually skip instantiation here */
+		change_world();
+		break;
+	}
+	return TRUE;
+}
+
+
+static GtkWidget *build_pkg_names(void)
+{
+	GtkWidget *hbox;
+	struct pkg *pkg;
+	GtkWidget *field;
+
+	hbox = gtk_hbox_new(FALSE, 0);
+	for (pkg = pkgs; pkg; pkg = pkg->next)
+		if (pkg->name) {
+			field = add_activator(hbox, pkg == active_pkg,
+			    pkg_select_event, pkg,
+			    "%s", pkg->name);
+			g_signal_connect(G_OBJECT(box_of_label(field)),
+			    "scroll_event",
+			    G_CALLBACK(pkg_scroll_event), NULL);
+		}
+	return hbox;
+}
+
+
 /* ----- frame labels ------------------------------------------------------ */
 
 
@@ -1428,7 +1495,7 @@ static GtkWidget *build_frame_refs(const struct frame *frame)
 void build_frames(GtkWidget *vbox)
 {
 	struct frame *frame;
-	GtkWidget *hbox, *tab, *label, *refs, *vars, *items, *meas;
+	GtkWidget *hbox, *tab, *label, *packages, *refs, *vars, *items, *meas;
 	int n = 0;
 
 	destroy_all_children(GTK_CONTAINER(vbox));
@@ -1444,9 +1511,12 @@ void build_frames(GtkWidget *vbox)
 	gtk_box_pack_start(GTK_BOX(hbox), tab, FALSE, FALSE, 0);
 	gtk_box_pack_start(GTK_BOX(vbox), hbox, FALSE, FALSE, 0);
 
-	label = build_part_name();
+	label = build_pkg_name();
 	gtk_table_attach_defaults(GTK_TABLE(tab), label, 0, 1, 0, 1);
 
+	packages = build_pkg_names();
+	gtk_table_attach_defaults(GTK_TABLE(tab), packages, 1, 2, 0, 1);
+
 	n = 0;
 	for (frame = root_frame; frame; frame = frame->prev) {
 		label = build_frame_label(frame);
diff --git a/gui_meas.c b/gui_meas.c
index 6a90640..5c4254a 100644
--- a/gui_meas.c
+++ b/gui_meas.c
@@ -63,7 +63,7 @@ static int is_min(lt_op_type lt, const struct inst *inst)
 {
 	struct coord min;
 
-	min = meas_find_min(lt, inst->vec->samples);
+	min = meas_find_min(lt, active_pkg->samples[inst->vec->n]);
 	return coord_eq(inst->u.rect.end, min);
 }
 
@@ -73,7 +73,8 @@ static int is_next(lt_op_type lt,
 {
 	struct coord next;
 
-	next = meas_find_next(lt, inst->vec->samples, ref->u.rect.end);
+	next = meas_find_next(lt, active_pkg->samples[inst->vec->n],
+	    ref->u.rect.end);
 	return coord_eq(inst->u.rect.end, next);
 }
 
@@ -82,7 +83,7 @@ static int is_max(lt_op_type lt, const struct inst *inst)
 {
 	struct coord max;
 
-	max = meas_find_max(lt, inst->vec->samples);
+	max = meas_find_max(lt, active_pkg->samples[inst->vec->n]);
 	return coord_eq(inst->u.rect.end, max);
 }
 
@@ -93,8 +94,9 @@ static int is_a_next(lt_op_type lt, struct inst *inst)
 	struct coord min, next;
 
 	for (a = insts_ip_vec(); a; a = a->next) {
-		min = meas_find_min(lt, a->vec->samples);
-		next = meas_find_next(lt, inst->vec->samples, min);
+		min = meas_find_min(lt, active_pkg->samples[a->vec->n]);
+		next = meas_find_next(lt, active_pkg->samples[inst->vec->n],
+		    min);
 		if (coord_eq(next, inst->u.rect.end))
 			return 1;
 	}
@@ -122,7 +124,7 @@ static int meas_pick_vec_a(struct inst *inst, void *ctx)
 {
 	struct vec *vec = inst->vec;
 
-	if (!vec->samples)
+	if (!active_pkg->samples[vec->n])
 		return 0;
 	if (is_min(meas_dsc->lt, inst)) {
 		mode = min_to_next_or_max;
@@ -145,7 +147,7 @@ static int meas_pick_vec_b(struct inst *inst, void *ctx)
 	struct vec *vec = inst->vec;
 	struct inst *a = ctx;
 
-	if (!vec->samples)
+	if (!active_pkg->samples[vec->n])
 		return 0;
 	switch (mode) {
 	case min_to_next_or_max:
@@ -337,7 +339,7 @@ static struct inst *vec_at(const struct vec *vec, struct coord pos)
 
 	for (inst = insts_ip_vec(); inst; inst = inst->next)
 		if (inst->vec == vec)
-			for (s = vec->samples; s; s = s->next)
+			for (s = active_pkg->samples[vec->n]; s; s = s->next)
 				if (coord_eq(s->pos, pos))
 					return inst;
 	abort();
diff --git a/gui_tool.c b/gui_tool.c
index 9c2a4a8..6fc2470 100644
--- a/gui_tool.c
+++ b/gui_tool.c
@@ -77,7 +77,6 @@ static struct vec *new_vec(struct inst *base)
 	vec->base = inst_get_vec(base);
 	vec->next = NULL;
 	vec->frame = active_frame;
-	vec->samples = NULL;
 	for (walk = &active_frame->vecs; *walk; walk = &(*walk)->next);
 	*walk = vec;
 	return vec;
diff --git a/inst.c b/inst.c
index 2ee8d51..5695cf2 100644
--- a/inst.c
+++ b/inst.c
@@ -31,12 +31,11 @@
 
 
 struct inst *selected_inst = NULL;
-struct inst *insts[ip_n];
 struct bbox active_frame_bbox;
+struct pkg *pkgs, *active_pkg, *curr_pkg;
+struct inst *curr_frame = NULL;
 
-static struct inst *curr_frame = NULL;
-static struct inst **next_inst[ip_n];
-static struct inst *prev_insts[ip_n];
+static struct pkg *prev_pkgs;
 
 static unsigned long active_set = 0;
 
@@ -171,7 +170,7 @@ int inst_select(struct coord pos)
 	FOR_INST_PRIOS_DOWN(prio) {
 		if (!show(prio))
 			continue;
-		for (inst = insts[prio]; inst; inst = inst->next) {
+		for (inst = active_pkg->insts[prio]; inst; inst = inst->next) {
 			if (!inst->active || !inst->ops->distance)
 				continue;
 			if (!inst_connected(inst))
@@ -191,7 +190,7 @@ int inst_select(struct coord pos)
 
 	/* give vectors a second chance */
 
-	for (inst = insts[ip_vec]; inst; inst = inst->next) {
+	for (inst = active_pkg->insts[ip_vec]; inst; inst = inst->next) {
 		if (!inst->active)
 			continue;
 		if (!inst_connected(inst))
@@ -219,7 +218,7 @@ struct inst *inst_find_point(struct coord pos)
 	int dist;
 
 	found = NULL;
-	for (inst = insts[ip_frame]; inst; inst = inst->next) {
+	for (inst = active_pkg->insts[ip_frame]; inst; inst = inst->next) {
 		if (!inst->u.frame.active)
 			continue;
 		dist = gui_dist_frame_eye(inst, pos, draw_ctx.scale);
@@ -231,7 +230,7 @@ struct inst *inst_find_point(struct coord pos)
 	if (found)
 		return found;
 
-	for (inst = insts[ip_vec]; inst; inst = inst->next) {
+	for (inst = active_pkg->insts[ip_vec]; inst; inst = inst->next) {
 		if (!inst->active || !inst->ops->distance)
 			continue;
 		dist = inst->ops->distance(inst, pos, draw_ctx.scale);
@@ -256,7 +255,8 @@ int inst_find_point_selected(struct coord pos, struct inst **res)
 	n = inst_anchors(selected_inst, anchors);
 	for (i = 0; i != n; i++) {
 		if (*anchors[i]) {
-			for (inst = insts[ip_vec]; inst; inst = inst->next) {
+			for (inst = active_pkg->insts[ip_vec]; inst;
+			    inst = inst->next) {
 				if (inst->vec != *anchors[i])
 					continue;
 				d = gui_dist_vec(inst, pos, draw_ctx.scale);
@@ -267,7 +267,8 @@ int inst_find_point_selected(struct coord pos, struct inst **res)
 				}
 			}
 		} else {
-			for (inst = insts[ip_frame]; inst; inst = inst->next) {
+			for (inst = active_pkg->insts[ip_frame]; inst; 
+			    inst = inst->next) {
 				if (inst != selected_inst->outer)
 					continue;
 				d = gui_dist_frame(inst, pos, draw_ctx.scale);
@@ -347,7 +348,7 @@ void inst_select_vec(struct vec *vec)
 
 	if (vec->frame != active_frame)
 		select_frame(vec->frame);
-	for (inst = insts[ip_vec]; inst; inst = inst->next)
+	for (inst = active_pkg->insts[ip_vec]; inst; inst = inst->next)
 		if (inst->vec == vec && inst->active) {
 			inst_deselect();
 			inst_select_inst(inst);
@@ -364,13 +365,20 @@ void inst_select_obj(struct obj *obj)
 
 	if (obj->frame != active_frame)
 		select_frame(obj->frame);
-	FOR_INSTS_DOWN(prio, inst)
-		if (inst->obj && inst->obj == obj && inst->active) {
-			inst_deselect();
-			inst_select_inst(inst);
-			return;
-		}
+	FOR_INST_PRIOS_DOWN(prio) {
+		FOR_GLOBAL_INSTS(prio, inst)
+			if (inst->obj && inst->obj == obj && inst->active)
+				goto found;
+		FOR_PKG_INSTS(prio, inst)
+			if (inst->obj && inst->obj == obj && inst->active)
+				goto found;
+	}
 	obj_edit(obj);
+	return;
+
+found:
+	inst_deselect();
+	inst_select_inst(inst);
 }
 
 
@@ -415,7 +423,8 @@ static void update_bbox(struct bbox *bbox, struct coord coord)
 
 static void propagate_bbox(const struct inst *inst)
 {
-	struct inst *frame = curr_frame ? curr_frame : insts[ip_frame];
+	struct inst *frame =
+	    curr_frame ? curr_frame : curr_pkg->insts[ip_frame];
 
 	update_bbox(&frame->bbox, inst->bbox.min);
 	update_bbox(&frame->bbox, inst->bbox.max);
@@ -445,8 +454,8 @@ static struct inst *add_inst(const struct inst_ops *ops, enum inst_prio prio,
 	inst->active = IS_ACTIVE;
 	inst->in_path = 0;
 	inst->next = NULL;
-	*next_inst[prio] = inst;
-	next_inst[prio] = &inst->next;
+	*curr_pkg->next_inst[prio] = inst;
+	curr_pkg->next_inst[prio] = &inst->next;
 	return inst;
 }
 
@@ -454,14 +463,6 @@ static struct inst *add_inst(const struct inst_ops *ops, enum inst_prio prio,
 /* ----- vec --------------------------------------------------------------- */
 
 
-static void vec_op_debug(struct inst *self)
-{
-	printf("vec %lg, %lg -> %lg, %lg\n",
-	    units_to_mm(self->base.x), units_to_mm(self->base.y),
-	    units_to_mm(self->u.rect.end.x), units_to_mm(self->u.rect.end.y));
-}
-
-
 static int validate_vec_name(const char *s, void *ctx)
 {
 	struct vec *vec = ctx;
@@ -525,7 +526,6 @@ static int vec_op_anchors(struct inst *inst, struct vec ***anchors)
 
 
 static struct inst_ops vec_ops = {
-	.debug		= vec_op_debug,
 	.draw		= gui_draw_vec,
 	.hover		= gui_hover_vec,
 	.distance	= gui_dist_vec,
@@ -552,14 +552,6 @@ int inst_vec(struct vec *vec, struct coord base)
 /* ----- line -------------------------------------------------------------- */
 
 
-static void line_op_debug(struct inst *self)
-{
-	printf("line %lg, %lg / %lg, %lg\n",
-	    units_to_mm(self->base.x), units_to_mm(self->base.y),
-	    units_to_mm(self->u.rect.end.x), units_to_mm(self->u.rect.end.y));
-}
-
-
 static void obj_line_edit(struct obj *obj)
 {
 	edit_expr(&obj->u.line.width);
@@ -584,7 +576,6 @@ static int line_op_anchors(struct inst *inst, struct vec ***anchors)
 
 
 static struct inst_ops line_ops = {
-	.debug		= line_op_debug,
 	.draw		= gui_draw_line,
 	.distance	= gui_dist_line,
 	.select		= line_op_select,
@@ -611,14 +602,6 @@ int inst_line(struct obj *obj, struct coord a, struct coord b, unit_type width)
 /* ----- rect -------------------------------------------------------------- */
 
 
-static void rect_op_debug(struct inst *self)
-{
-	printf("rect %lg, %lg / %lg, %lg\n",
-	    units_to_mm(self->base.x), units_to_mm(self->base.y),
-	    units_to_mm(self->u.rect.end.x), units_to_mm(self->u.rect.end.y));
-}
-
-
 static void obj_rect_edit(struct obj *obj)
 {
 	edit_expr(&obj->u.rect.width);
@@ -633,7 +616,6 @@ static void rect_op_select(struct inst *self)
 
 
 static struct inst_ops rect_ops = {
-	.debug		= rect_op_debug,
 	.draw		= gui_draw_rect,
 	.distance	= gui_dist_rect,
 	.select		= rect_op_select,
@@ -660,21 +642,6 @@ int inst_rect(struct obj *obj, struct coord a, struct coord b, unit_type width)
 /* ----- pad / rpad -------------------------------------------------------- */
 
 
-static void pad_op_debug(struct inst *self)
-{
-	printf("pad \"%s\" %lg, %lg / %lg, %lg\n", self->u.name,
-	    units_to_mm(self->base.x), units_to_mm(self->base.y),
-	    units_to_mm(self->u.pad.other.x), units_to_mm(self->u.pad.other.y));
-}
-
-
-static void rpad_op_debug(struct inst *self)
-{
-	printf("r");
-	pad_op_debug(self);
-}
-
-
 static int validate_pad_name(const char *s, void *ctx)
 {
 	char *tmp;
@@ -713,7 +680,6 @@ static int pad_op_anchors(struct inst *inst, struct vec ***anchors)
 
 
 static struct inst_ops pad_ops = {
-	.debug		= pad_op_debug,
 	.draw		= gui_draw_pad,
 	.distance	= gui_dist_pad,
 	.select		= pad_op_select,
@@ -723,7 +689,6 @@ static struct inst_ops pad_ops = {
 
 
 static struct inst_ops rpad_ops = {
-	.debug		= rpad_op_debug,
 	.draw		= gui_draw_rpad,
 	.distance	= gui_dist_pad, /* @@@ */
 	.select		= pad_op_select,
@@ -749,14 +714,6 @@ int inst_pad(struct obj *obj, const char *name, struct coord a, struct coord b)
 /* ----- arc --------------------------------------------------------------- */
 
 
-static void arc_op_debug(struct inst *self)
-{
-	printf("arc %lg, %lg radius %lg %lg ... %lg\n",
-	    units_to_mm(self->base.x), units_to_mm(self->base.y),
-	    units_to_mm(self->u.arc.r), self->u.arc.a1, self->u.arc.a2);
-}
-
-
 static void obj_arc_edit(struct obj *obj)
 {
 	edit_expr(&obj->u.arc.width);
@@ -788,7 +745,6 @@ static int arc_op_anchors(struct inst *inst, struct vec ***anchors)
 
 
 static struct inst_ops arc_ops = {
-	.debug		= arc_op_debug,
 	.draw		= gui_draw_arc,
 	.distance	= gui_dist_arc,
 	.select		= arc_op_select,
@@ -827,15 +783,6 @@ int inst_arc(struct obj *obj, struct coord center, struct coord start,
 /* ----- measurement ------------------------------------------------------- */
 
 
-static void meas_op_debug(struct inst *self)
-{
-	printf("meas %lg, %lg / %lg, %lg offset %lg\n",
-	    units_to_mm(self->base.x), units_to_mm(self->base.y),
-	    units_to_mm(self->u.meas.end.x), units_to_mm(self->u.meas.end.y),
-	    units_to_mm(self->u.meas.offset));
-}
-
-
 static void obj_meas_edit(struct obj *obj)
 {
 	edit_expr(&obj->u.meas.offset);
@@ -862,7 +809,6 @@ static int meas_op_anchors(struct inst *inst, struct vec ***anchors)
 
 
 static struct inst_ops meas_ops = {
-	.debug		= meas_op_debug,
 	.draw		= gui_draw_meas,
 	.distance	= gui_dist_meas,
 	.select		= meas_op_select,
@@ -943,14 +889,6 @@ void inst_end_active(void)
 /* ----- frame ------------------------------------------------------------- */
 
 
-static void frame_op_debug(struct inst *self)
-{
-	printf("frame %s @ %lg, %lg\n",
-	    self->u.frame.ref->name ? self->u.frame.ref->name : "(root)",
-	    units_to_mm(self->base.x), units_to_mm(self->base.y));
-}
-
-
 static void frame_op_select(struct inst *self)
 {
 	rect_status(self->bbox.min, self->bbox.max, -1);
@@ -967,7 +905,6 @@ static int frame_op_anchors(struct inst *inst, struct vec ***anchors)
 
 
 static struct inst_ops frame_ops = {
-	.debug		= frame_op_debug,
 	.draw		= gui_draw_frame,
 	.hover		= gui_hover_frame,
 	.distance	= gui_dist_frame,
@@ -1003,56 +940,91 @@ void inst_end_frame(const struct frame *frame)
 }
 
 
+/* ----- package ----------------------------------------------------------- */
+
+
+void inst_select_pkg(const char *name)
+{
+	struct pkg **pkg;
+	enum inst_prio prio;
+
+	name = name ? unique(name) : NULL;
+	for (pkg = &pkgs; *pkg; pkg = &(*pkg)->next)
+		if ((*pkg)->name == name)
+			break;
+	if (!*pkg) {
+		*pkg = zalloc_type(struct pkg);
+		(*pkg)->name = name;
+		FOR_INST_PRIOS_UP(prio)
+			(*pkg)->next_inst[prio] = &(*pkg)->insts[prio];
+		(*pkg)->samples =
+		    zalloc_size(sizeof(struct sample *)*n_samples);
+	}
+	curr_pkg = *pkg;
+}
+
+
 /* ----- misc. ------------------------------------------------------------- */
 
 
 struct bbox inst_get_bbox(void)
 {
-	return insts[ip_frame]->bbox;
+	return pkgs->insts[ip_frame]->bbox;
 }
 
 
-static void inst_free(struct inst *list[ip_n])
+static void free_pkgs(struct pkg *pkg)
 {
 	enum inst_prio prio;
-	struct inst *next;
+	struct pkg *next_pkg;
+	struct inst *inst, *next;
 
-	FOR_INST_PRIOS_UP(prio)
-		while (list[prio]) {
-			next = list[prio]->next;
-			free(list[prio]);
-			list[prio] = next;
-		}
+	while (pkg) {
+		next_pkg = pkg->next;
+		FOR_INST_PRIOS_UP(prio)
+			for (inst = pkg->insts[prio]; inst; inst = next) {
+				next = inst->next;
+				free(inst);
+			}
+		reset_samples(pkg->samples);
+		free(pkg->samples);
+		free(pkg);
+		pkg = next_pkg;
+	}
 }
 
 
 void inst_start(void)
 {
 	static struct bbox bbox_zero = { { 0, 0 }, { 0, 0 }};
-	enum inst_prio prio;
 
 	active_frame_bbox = bbox_zero;
-	FOR_INST_PRIOS_UP(prio) {
-		prev_insts[prio] = insts[prio];
-		insts[prio] = NULL;
-		next_inst[prio] = &insts[prio];
-	}
+	prev_pkgs = pkgs;
+	pkgs = NULL;
+	inst_select_pkg(NULL);
+	curr_pkg = pkgs;
 }
 
 
 void inst_commit(void)
 {
-	inst_free(prev_insts);
+	struct pkg *pkg;
+
+	if (active_pkg) {
+		for (pkg = pkgs; pkgs && pkg->name != active_pkg->name;
+		    pkg = pkg->next);
+		active_pkg = pkg;
+	}
+	if (!active_pkg)
+		active_pkg = pkgs->next;
+	free_pkgs(prev_pkgs);
 }
 
 
 void inst_revert(void)
 {
-	enum inst_prio prio;
-
-	inst_free(insts);
-	FOR_INST_PRIOS_UP(prio)
-		insts[prio] = prev_insts[prio];
+	free_pkgs(pkgs);
+	pkgs = prev_pkgs;
 }
 
 
@@ -1061,18 +1033,34 @@ void inst_draw(void)
 	enum inst_prio prio;
 	struct inst *inst;
 
-	FOR_INSTS_UP(prio, inst)
-		if (show(prio) && !inst->active && inst->ops->draw)
-			inst->ops->draw(inst);
-	FOR_INSTS_UP(prio, inst)
-		if (show(prio) && prio != ip_frame && inst->active &&
-		    inst != selected_inst && inst->ops->draw)
-			inst->ops->draw(inst);
-	if (show_stuff)
-		for (inst = insts[ip_frame]; inst; inst = inst->next)
+	FOR_INST_PRIOS_UP(prio) {
+		FOR_GLOBAL_INSTS(prio, inst)
+			if (show(prio) && !inst->active && inst->ops->draw)
+				inst->ops->draw(inst);
+		FOR_PKG_INSTS(prio, inst)
+			if (show(prio) && !inst->active && inst->ops->draw)
+				inst->ops->draw(inst);
+	}
+	FOR_INST_PRIOS_UP(prio) {
+		FOR_GLOBAL_INSTS(prio, inst)
+			if (show(prio) && prio != ip_frame && inst->active &&
+			    inst != selected_inst && inst->ops->draw)
+				inst->ops->draw(inst);
+		FOR_PKG_INSTS(prio, inst)
+			if (show(prio) && prio != ip_frame && inst->active &&
+			    inst != selected_inst && inst->ops->draw)
+				inst->ops->draw(inst);
+	}
+	if (show_stuff) {
+		FOR_GLOBAL_INSTS(ip_frame, inst)
 			if (inst->active && inst != selected_inst &&
 			    inst->ops->draw)
 				inst->ops->draw(inst);
+		FOR_PKG_INSTS(ip_frame, inst)
+			if (inst->active && inst != selected_inst &&
+			    inst->ops->draw)
+				inst->ops->draw(inst);
+	}
 	if (selected_inst && selected_inst->ops->draw)
 		selected_inst->ops->draw(selected_inst);
 }
@@ -1082,7 +1070,10 @@ void inst_highlight_vecs(int (*pick)(struct inst *inst, void *user), void *user)
 {
 	struct inst *inst;
 
-	for (inst = insts[ip_vec]; inst; inst = inst->next)
+	FOR_GLOBAL_INSTS(ip_vec, inst)
+		if (pick(inst, user))
+			gui_highlight_vec(inst);
+	FOR_PKG_INSTS(ip_vec, inst)
 		if (pick(inst, user))
 			gui_highlight_vec(inst);
 }
@@ -1096,7 +1087,18 @@ struct inst *inst_find_vec(struct coord pos,
 	int dist;
 
 	found = NULL;
-	for (inst = insts[ip_vec]; inst; inst = inst->next) {
+	FOR_GLOBAL_INSTS(ip_vec, inst) {
+		if (!inst->ops->distance)
+			continue;
+		dist = inst->ops->distance(inst, pos, draw_ctx.scale);
+		if (dist < 0 || (found && best_dist <= dist))
+			continue;
+		if (!pick(inst, user))
+			continue;
+		found = inst;
+		best_dist = dist;
+	}
+	FOR_PKG_INSTS(ip_vec, inst) {
 		if (!inst->ops->distance)
 			continue;
 		dist = inst->ops->distance(inst, pos, draw_ctx.scale);
@@ -1113,7 +1115,7 @@ struct inst *inst_find_vec(struct coord pos,
 
 struct inst *insts_ip_vec(void)
 {
-	return insts[ip_vec];
+	return active_pkg->insts[ip_vec];
 }
 
 
@@ -1154,13 +1156,3 @@ void inst_delete(struct inst *inst)
 	else
 		delete_obj(inst->obj);
 }
-
-
-void inst_debug(void)
-{
-	enum inst_prio prio;
-	struct inst *inst;
-
-	FOR_INSTS_UP(prio, inst)
-		inst->ops->debug(inst);
-}
diff --git a/inst.h b/inst.h
index 8f79284..b929769 100644
--- a/inst.h
+++ b/inst.h
@@ -109,10 +109,32 @@ struct inst {
 };
 
 
+struct pkg {
+	const char *name;	/* NULL if global package */
+	struct inst *insts[ip_n];
+	struct inst **next_inst[ip_n];
+	struct sample **samples;
+	struct pkg *next;
+};
+
+
 extern struct inst *selected_inst;
-extern struct inst *insts[ip_n];
+extern struct pkg *pkgs;	/* list of packages */
+extern struct pkg *active_pkg;	/* package selected in GUI */
+extern struct pkg *curr_pkg;	/* package currently being instantiated */
 extern struct bbox active_frame_bbox;
 
+/*
+ * frame being instantiated - we need to export this one for meas.c, so that
+ * measurement scan update the root frame's bounding box.
+ */
+extern	struct inst *curr_frame;
+
+/*
+ * @@@ Note that we over-generalize a bit here: the only item that ever ends up
+ * in the global package is currently the root frame. However, we may later
+ * allow other items shared by all packages be there as well.
+ */
 
 #define FOR_INST_PRIOS_UP(prio)					\
 	for (prio = 0; prio != ip_n; prio++)
@@ -120,13 +142,11 @@ extern struct bbox active_frame_bbox;
 #define FOR_INST_PRIOS_DOWN(prio)				\
 	for (prio = ip_n-1; prio != (enum inst_prio) -1; prio--)
 
-#define	FOR_INSTS_UP(prio, inst)				\
-	FOR_INST_PRIOS_UP(prio)					\
-		for (inst = insts[prio]; inst; inst = inst->next)
+#define	FOR_GLOBAL_INSTS(prio, inst)			\
+	for (inst = pkgs->insts[prio]; inst; inst = inst->next)
 
-#define	FOR_INSTS_DOWN(prio, inst)				\
-	FOR_INST_PRIOS_DOWN(prio)				\
-		for (inst = insts[prio]; inst; inst = inst->next)
+#define	FOR_PKG_INSTS(prio, inst)				\
+	for (inst = active_pkg->insts[prio]; inst; inst = inst->next)
 
 
 void inst_select_outside(void *item, void (*deselect)(void *item));
@@ -158,6 +178,8 @@ void inst_begin_frame(struct obj *obj, const struct frame *frame,
     struct coord base, int active, int is_active_frame);
 void inst_end_frame(const struct frame *frame);
 
+void inst_select_pkg(const char *name);
+
 struct bbox inst_get_bbox(void);
 
 void inst_start(void);
@@ -176,6 +198,5 @@ int inst_do_move_to(struct inst *inst, struct inst *to, int i);
 struct pix_buf *inst_hover(struct inst *inst);
 void inst_begin_drag_move(struct inst *inst, int i);
 void inst_delete(struct inst *inst);
-void inst_debug(void);
 
 #endif /* !INST_H */
diff --git a/kicad.c b/kicad.c
index 38e4349..f889cea 100644
--- a/kicad.c
+++ b/kicad.c
@@ -208,7 +208,7 @@ static void kicad_inst(FILE *file, enum inst_prio prio, const struct inst *inst)
 }
 
 
-static void kicad_module(FILE *file, const char *name, time_t now)
+static void kicad_module(FILE *file, const struct pkg *pkg, time_t now)
 {
 	enum inst_prio prio;
 	const struct inst *inst;
@@ -216,7 +216,7 @@ static void kicad_module(FILE *file, const char *name, time_t now)
 	/*
 	 * Module library name
 	 */
-	fprintf(file, "$MODULE %s\n", name);
+	fprintf(file, "$MODULE %s\n", pkg->name);
 
 	/*
 	 * Xpos = 0, Ypos = 0, 15 layers, last modification, timestamp,
@@ -227,13 +227,13 @@ static void kicad_module(FILE *file, const char *name, time_t now)
 	/*
 	 * Module library name again
 	 */
-	fprintf(file, "Li %s\n", name);
+	fprintf(file, "Li %s\n", pkg->name);
 
 #if 0 /* optional */
 	/*
 	 * Description
 	 */
-	fprintf(file, "Cd %s\n", name);
+	fprintf(file, "Cd %s\n", pkg->name);
 #endif
 
 	/*
@@ -258,28 +258,37 @@ static void kicad_module(FILE *file, const char *name, time_t now)
 	 */
 
 	fprintf(file, "T0 0 -150 200 200 0 40 N V %d \"%s\"\n",
-	    layer_comment, name);
+	    layer_comment, pkg->name);
 	fprintf(file, "T1 0 150 200 200 0 40 N I %d \"Val*\"\n",
 	    layer_comment);
 
-	FOR_INSTS_UP(prio, inst)
-		kicad_inst(file, prio, inst);
+	FOR_INST_PRIOS_UP(prio) {
+		for (inst = pkgs->insts[prio]; inst; inst = inst->next)
+			kicad_inst(file, prio, inst);
+		for (inst = pkg->insts[prio]; inst; inst = inst->next)
+			kicad_inst(file, prio, inst);
+	}
 
-	fprintf(file, "$EndMODULE %s\n", name);
+	fprintf(file, "$EndMODULE %s\n", pkg->name);
 }
 
 
 int kicad(FILE *file)
 {
+	const struct pkg *pkg;
 	time_t now = time(NULL);
 
 	fprintf(file, "PCBNEW-LibModule-V1 %s", ctime(&now));
 
 	fprintf(file, "$INDEX\n");
-	fprintf(file, "%s\n", part_name);
+	for (pkg = pkgs; pkg; pkg = pkg->next)
+		if (pkg->name)
+			fprintf(file, "%s\n", pkg->name);
 	fprintf(file, "$EndINDEX\n");
 
-	kicad_module(file, part_name, now);
+	for (pkg = pkgs; pkg; pkg = pkg->next)
+		if (pkg->name)
+			kicad_module(file, pkg, now);
 
 	fprintf(file, "$EndLIBRARY\n");
 
diff --git a/meas.c b/meas.c
index d2232fa..7c70327 100644
--- a/meas.c
+++ b/meas.c
@@ -21,37 +21,43 @@
 #include "meas.h"
 
 
+int n_samples;
+
+
 struct num eval_unit(const struct expr *expr, const struct frame *frame);
 
 
-static void reset_samples(struct sample **samples)
+void reset_samples(struct sample **samples)
 {
 	struct sample *next;
+	int i;
 
-	while (*samples) {
-		next = (*samples)->next;
-		free(*samples);
-		*samples = next;
-	}
+	for (i = 0; i != n_samples; i++)
+		while (samples[i]) {
+			next = samples[i]->next;
+			free(samples[i]);
+			samples[i] = next;
+		}
 }
 
 
 void meas_start(void)
 {
-	struct frame *frame;
+	const struct frame *frame;
 	struct vec *vec;
 
+	n_samples = 0;
 	for (frame = frames; frame; frame = frame->next)
 		for (vec = frame->vecs; vec; vec = vec->next)
-			reset_samples(&vec->samples);
+			vec->n = n_samples++;
 }
 
 
-void meas_post(struct vec *vec, struct coord pos)
+void meas_post(const struct vec *vec, struct coord pos)
 {
 	struct sample **walk, *new;
 
-	for (walk = &vec->samples; *walk; walk = &(*walk)->next) {
+	for (walk = &curr_pkg->samples[vec->n]; *walk; walk = &(*walk)->next) {
 		if (pos.y < (*walk)->pos.y)
 			break;
 		if (pos.y > (*walk)->pos.y)
@@ -219,7 +225,7 @@ struct coord meas_find_max(lt_op_type lt, const struct sample *s)
 /* ----- instantiation ----------------------------------------------------- */
 
 
-int instantiate_meas(void)
+static int instantiate_meas_pkg(void)
 {
 	struct obj *obj;
 	const struct meas *meas;
@@ -231,15 +237,18 @@ int instantiate_meas(void)
 		if (obj->type != ot_meas)
 			continue;
 		meas = &obj->u.meas;
-		if (!obj->base->samples || !meas->high->samples)
+		if (!curr_pkg->samples[obj->base->n] ||
+		    !curr_pkg->samples[meas->high->n])
 			continue;
 
 		lt = lt_op[meas->type];
-		a0 = meas_find_min(lt, obj->base->samples);
+		a0 = meas_find_min(lt, curr_pkg->samples[obj->base->n]);
 		if (is_next[meas->type])
-			b0 = meas_find_next(lt, meas->high->samples, a0);
+			b0 = meas_find_next(lt,
+			    curr_pkg->samples[meas->high->n], a0);
 		else
-			b0 = meas_find_max(lt, meas->high->samples);
+			b0 = meas_find_max(lt,
+			    curr_pkg->samples[meas->high->n]);
 
 		if (!meas->offset)
 			offset.n = 0;
@@ -256,3 +265,18 @@ int instantiate_meas(void)
 	}
 	return 1;
 }
+
+
+int instantiate_meas(void)
+{
+	struct pkg *pkg;
+
+	curr_frame = pkgs->insts[ip_frame];
+	for (pkg = pkgs; pkg; pkg = pkg->next)
+		if (pkg->name) {
+			inst_select_pkg(pkg->name);
+			if (!instantiate_meas_pkg())
+				return 0;
+		}
+	return 1;
+}
diff --git a/meas.h b/meas.h
index 5ff7913..1d42341 100644
--- a/meas.h
+++ b/meas.h
@@ -47,6 +47,9 @@ struct sample {
 };
 
 
+extern int n_samples;
+
+
 int lt_x(struct coord a, struct coord b);
 int lt_y(struct coord a, struct coord b);
 int lt_xy(struct coord a, struct coord b);
@@ -56,8 +59,10 @@ struct coord meas_find_next(lt_op_type lt, const struct sample *s,
     struct coord ref);
 struct coord meas_find_max(lt_op_type lt, const struct sample *s);
 
+
+void reset_samples(struct sample **samples);
 void meas_start(void);
-void meas_post(struct vec *vec, struct coord pos);
+void meas_post(const struct vec *vec, struct coord pos);
 int instantiate_meas(void);
 
 #endif /* !MEAS_H */
diff --git a/obj.c b/obj.c
index 58ca1e4..be04432 100644
--- a/obj.c
+++ b/obj.c
@@ -28,7 +28,7 @@
 #define	MAX_ITERATIONS	1000	/* abort "loop"s at this limit */
 
 
-char *part_name = NULL;
+char *pkg_name = NULL;
 struct frame *frames = NULL;
 struct frame *root_frame = NULL;
 struct frame *active_frame = NULL;
@@ -163,8 +163,14 @@ error:
 
 static int generate_items(struct frame *frame, struct coord base, int active)
 {
+	char *s;
 	int ok;
 
+	if (!frame->name) {
+		s = expand(pkg_name, frame);
+		inst_select_pkg(s);
+		free(s);
+	}
 	inst_begin_active(active && frame == active_frame);
 	ok = generate_vecs(frame, base) && generate_objs(frame, base, active);
 	inst_end_active();
@@ -270,8 +276,8 @@ int instantiate(void)
 	struct coord zero = { 0, 0 };
 	int ok;
 
-	inst_start();
 	meas_start();
+	inst_start();
 	instantiation_error = NULL;
 	ok = generate_frame(root_frame, zero, NULL, NULL, 1);
 	if (ok)
diff --git a/obj.h b/obj.h
index e272f8c..e637ec3 100644
--- a/obj.h
+++ b/obj.h
@@ -100,8 +100,8 @@ struct vec {
 	/* used when editing */
 	struct frame *frame;
 
-	/* samples for measurements */
-	struct sample *samples;
+	/* index into table of samples */
+	int n;
 
 	/* for the GUI */
 	GtkWidget *list_widget; /* NULL if items aren't shown */
@@ -180,7 +180,7 @@ struct obj {
 };
 
 
-extern char *part_name;
+extern char *pkg_name;
 extern struct frame *frames;
 extern struct frame *root_frame;
 extern struct frame *active_frame;
diff --git a/postscript.c b/postscript.c
index 6285abb..3574715 100644
--- a/postscript.c
+++ b/postscript.c
@@ -373,10 +373,18 @@ fprintf(file,
 "    dup false charpath stroke grestore\n"
 "    show } def\n");
 
-	FOR_INSTS_UP(prio, inst)
-		ps_background(file, prio, inst);
-	FOR_INSTS_UP(prio, inst)
-		ps_foreground(file, prio, inst);
+	FOR_INST_PRIOS_UP(prio) {
+		FOR_GLOBAL_INSTS(prio, inst)
+			ps_background(file, prio, inst);
+		FOR_PKG_INSTS(prio, inst)
+			ps_background(file, prio, inst);
+	}
+	FOR_INST_PRIOS_UP(prio) {
+		FOR_GLOBAL_INSTS(prio, inst)
+			ps_foreground(file, prio, inst);
+		FOR_PKG_INSTS(prio, inst)
+			ps_foreground(file, prio, inst);
+	}
 
 	fprintf(file, "showpage\n");
 	fprintf(file, "%%%%EOF\n");
diff --git a/util.h b/util.h
index 173b38f..feb1e59 100644
--- a/util.h
+++ b/util.h
@@ -27,6 +27,11 @@
 
 #define alloc_type(t) ((t *) alloc_size(sizeof(t)))
 
+#define	zalloc_size(s)					\
+    ({	void *zalloc_size_tmp = alloc_size(s);		\
+	memset(zalloc_size_tmp, 0, (s));		\
+	zalloc_size_tmp; })
+
 #define zalloc_type(t)					\
     ({	t *zalloc_type_tmp = alloc_type(t);		\
 	memset(zalloc_type_tmp, 0, sizeof(t));		\