From 220563012d2aa2c753c791fa9faa38346f1355a5 Mon Sep 17 00:00:00 2001
From: "Y. Wang" <yw05@forksworld.de>
Date: Fri, 6 May 2022 21:36:21 +0200
Subject: Record signal aspect to avoid excessive get_aspect calls; report
 testing coverage

---
 .../spec/fixtures/advtrains_helpers.lua            |  1 +
 advtrains_interlocking/spec/mineunit.conf          |  0
 advtrains_interlocking/spec/signal_api_spec.lua    | 50 ++++++++++++++++++++++
 3 files changed, 51 insertions(+)
 create mode 120000 advtrains_interlocking/spec/fixtures/advtrains_helpers.lua
 create mode 100644 advtrains_interlocking/spec/mineunit.conf
 create mode 100644 advtrains_interlocking/spec/signal_api_spec.lua

(limited to 'advtrains_interlocking/spec')

diff --git a/advtrains_interlocking/spec/fixtures/advtrains_helpers.lua b/advtrains_interlocking/spec/fixtures/advtrains_helpers.lua
new file mode 120000
index 0000000..9b0ab67
--- /dev/null
+++ b/advtrains_interlocking/spec/fixtures/advtrains_helpers.lua
@@ -0,0 +1 @@
+../../../advtrains/helpers.lua
\ No newline at end of file
diff --git a/advtrains_interlocking/spec/mineunit.conf b/advtrains_interlocking/spec/mineunit.conf
new file mode 100644
index 0000000..e69de29
diff --git a/advtrains_interlocking/spec/signal_api_spec.lua b/advtrains_interlocking/spec/signal_api_spec.lua
new file mode 100644
index 0000000..2659380
--- /dev/null
+++ b/advtrains_interlocking/spec/signal_api_spec.lua
@@ -0,0 +1,50 @@
+require("mineunit")
+
+mineunit("core")
+
+_G.advtrains = {
+	interlocking = {
+		aspects = sourcefile("signal_aspects"),
+		--aspects = fixture("../../signal_aspects"),
+	},
+	ndb = {
+		get_node = minetest.get_node,
+	}
+}
+
+fixture("advtrains_helpers")
+fixture("../../database")
+sourcefile("signal_api")
+
+local stub_aspect_t1 = { main = math.random() }
+local stub_pos_t1 = {x = 1, y = 0, z = 1}
+
+minetest.register_node(":stubsignal_t1", {
+	advtrains = {
+		supported_aspects = {},
+		get_aspect = function () return stub_aspect_t1 end,
+		set_aspect = function () end,
+	},
+	groups = { advtrains_signal = 2 },
+})
+
+world.layout {
+	{stub_pos_t1, "stubsignal_t1"},
+}
+
+describe("API for supposed signal aspects", function()
+	it("should load and save data properly", function()
+		local tbl = {_foo = true}
+		advtrains.interlocking.load_supposed_aspects(tbl)
+		assert.same(tbl, advtrains.interlocking.save_supposed_aspects())
+	end)
+	it("should set and get type 1 signals properly", function ()
+		local pos = stub_pos_t1
+		local asp = stub_aspect_t1
+		local newasp = { dst = math.random() }
+		assert.same(asp, advtrains.interlocking.signal_get_aspect(pos))
+		advtrains.interlocking.signal_set_aspect(pos, newasp)
+		assert.same(newasp, advtrains.interlocking.signal_get_aspect(pos))
+		assert.same(asp, advtrains.interlocking.signal_get_real_aspect(pos))
+	end)
+end)
-- 
cgit v1.2.3


From d1a0d8f2654d6ee64c1a43de7958b1eadfaff6b0 Mon Sep 17 00:00:00 2001
From: "Y. Wang" <yw05@forksworld.de>
Date: Fri, 10 Jun 2022 22:21:54 +0200
Subject: Use tabs to switch between signaling and IP forms

---
 .gitignore                                      |   1 +
 advtrains/formspec.lua                          |  36 +++++-
 advtrains_interlocking/signal_api.lua           |  11 +-
 advtrains_interlocking/signal_aspect_ui.lua     | 165 ++++++++++++++++++------
 advtrains_interlocking/signal_aspects.lua       |   2 +-
 advtrains_interlocking/signal_main_ui.lua       |   0
 advtrains_interlocking/spec/signal_api_spec.lua |   3 +-
 advtrains_interlocking/tcb_ts_ui.lua            |  25 ++--
 8 files changed, 176 insertions(+), 67 deletions(-)
 create mode 100644 advtrains_interlocking/signal_main_ui.lua

(limited to 'advtrains_interlocking/spec')

diff --git a/.gitignore b/.gitignore
index b3180de..bef77f1 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
 ## Eclipse project files & directories
 .project
 .settings
+luacov.*
diff --git a/advtrains/formspec.lua b/advtrains/formspec.lua
index 91e300d..aa5aa69 100644
--- a/advtrains/formspec.lua
+++ b/advtrains/formspec.lua
@@ -1,6 +1,14 @@
 local sformat = string.format
 local fsescape = minetest.formspec_escape
 
+local function make_list(entries)
+	local t = {}
+	for k, v in ipairs(entries) do
+		t[k] = fsescape(v)
+	end
+	return table.concat(t, ",")
+end
+
 local function f_button_exit(x, y, w, h, id, text)
 	return sformat("button_exit[%f,%f;%f,%f;%s;%s]", x, y, w, h, id, text)
 end
@@ -10,12 +18,8 @@ local function S_button_exit(x, y, w, h, id, ...)
 end
 
 local function f_dropdown(x, y, w, id, entries, sel, indexed)
-	local t = {}
-	for k, v in pairs(entries) do
-		t[k] = fsescape(v)
-	end
 	return sformat("dropdown[%f,%f;%f;%s;%s;%d%s]",
-		x, y, w, id, table.concat(t, ","),
+		x, y, w, id, make_list(entries),
 		sel or 1,
 		indexed and ";true" or "")
 end
@@ -28,10 +32,32 @@ local function S_label(x, y, ...)
 	return f_label(x, y, attrans(...))
 end
 
+local function f_tabheader(x, y, w, h, id, entries, sel, transparent, border)
+	local st = {string.format("%f,%f",x, y)}
+	if h then
+		if w then
+			st[#st+1] = string.format("%f,%f", w, h)
+		else
+			st[#st+1] = tostring(h)
+		end
+	end
+	st[#st+1] = tostring(id)
+	st[#st+1] = make_list(entries)
+	st[#st+1] = tostring(sel)
+	if transparent ~= nil then
+		st[#st+1] = tostring(transparent)
+		if border ~= nil then
+			st[#st+1] = tostring(border)
+		end
+	end
+	return string.format("tabheader[%s]", table.concat(st, ";"))
+end
+
 return {
 	button_exit = f_button_exit,
 	S_button_exit = S_button_exit,
 	dropdown = f_dropdown,
 	label = f_label,
 	S_label = S_label,
+	tabheader = f_tabheader,
 }
diff --git a/advtrains_interlocking/signal_api.lua b/advtrains_interlocking/signal_api.lua
index a25e1f6..5b3baf8 100644
--- a/advtrains_interlocking/signal_api.lua
+++ b/advtrains_interlocking/signal_api.lua
@@ -272,7 +272,10 @@ function advtrains.interlocking.signal_rc_handler(pos, node, player, itemstack,
 		advtrains.interlocking.show_ip_form(pos, pname)
 		return
 	end
+	advtrains.interlocking.show_signal_form(pos, node, pname)
+end
 	
+function advtrains.interlocking.show_signal_form(pos, node, pname)
 	local sigd = advtrains.interlocking.db.get_sigd_for_signal(pos)
 	if sigd then
 		advtrains.interlocking.show_signalling_form(sigd, pname)
@@ -288,7 +291,7 @@ function advtrains.interlocking.signal_rc_handler(pos, node, player, itemstack,
 			advtrains.interlocking.show_signal_aspect_selector(
 				pname,
 				ndef.advtrains.supported_aspects,
-				"Set aspect manually", callback,
+				pos, callback,
 				isasp)
 		else
 			--static signal - only IP
@@ -332,7 +335,7 @@ function advtrains.interlocking.signal_get_aspect(pos)
 	local asp = get_supposed_aspect(pos)
 	if not asp then
 		asp = advtrains.interlocking.signal_get_real_aspect(pos)
-		set_supposed_aspect(pos)
+		set_supposed_aspect(pos, asp)
 	end
 	return asp
 end
@@ -372,6 +375,7 @@ function advtrains.interlocking.show_ip_form(pos, pname, only_notset)
 		return
 	end
 	local form = "size[7,5]label[0.5,0.5;Signal at "..minetest.pos_to_string(pos).."]"
+	form = form .. advtrains.interlocking.make_signal_formspec_tabheader(pname, pos, 7, 2)
 	advtrains.interlocking.db.check_for_duplicate_ip(pos)
 	local pts, connid = advtrains.interlocking.db.get_ip_by_signalpos(pos)
 	if pts then
@@ -394,6 +398,9 @@ end
 
 minetest.register_on_player_receive_fields(function(player, formname, fields)
 	local pname = player:get_player_name()
+	if advtrains.interlocking.handle_signal_formspec_tabheader_fields(pname, fields) then
+		return true
+	end
 	if not minetest.check_player_privs(pname, {train_operator=true, interlocking=true}) then
 		return
 	end
diff --git a/advtrains_interlocking/signal_aspect_ui.lua b/advtrains_interlocking/signal_aspect_ui.lua
index edf3ab1..4b41187 100644
--- a/advtrains_interlocking/signal_aspect_ui.lua
+++ b/advtrains_interlocking/signal_aspect_ui.lua
@@ -1,63 +1,136 @@
 local F = advtrains.formspec
 local players_aspsel = {}
 
-local function make_signal_aspect_selector_t1(suppasp, purpose, isasp)
-	local form = {"size[7,7.5]"}
-	form[#form+1] = F.S_label(0.5, 0.5, "Select signal aspect")
-	form[#form+1] = F.label(0.5, 1, purpose)
+local function describe_t1_main_aspect(spv)
+	if spv == 0 then
+		return attrans("Danger (halt)")
+	elseif spv == -1 then
+		return attrans("Continue at maximum speed")
+	elseif not spv then
+		return attrans("Continue with current speed limit")
+	else
+		return attrans("Continue with the speed limit of @1", tostring(spv))
+	end
+end
+
+local function describe_t1_shunt_aspect(shunt)
+	if shunt then
+		return attrans("Shunting allowed")
+	else
+		return attrans("No shunting")
+	end
+end
+
+local function describe_t1_distant_aspect(spv)
+	if spv == 0 then
+		return attrans("Expect to stop at the next signal")
+	elseif spv == -1 then
+		return attrans("Expect to continue at maximum speed")
+	elseif not spv then
+		return attrans("No distant signal information")
+	else
+		return attrans("Expect to continue with a speed limit of @1", tostring(spv))
+	end
+end
+
+advtrains.interlocking.describe_t1_main_aspect = describe_t1_main_aspect
+advtrains.interlocking.describe_t1_shunt_aspect = describe_t1_shunt_aspect
+advtrains.interlocking.describe_t1_distant_aspect = describe_t1_distant_aspect
+
+local function describe_supported_aspects_t1(suppasp, isasp)
+	local t = {}
 
-	form[#form+1] = F.S_label(0.5, 1.5, "Main aspect")
 	local entries = {}
 	local selid = 1
 	for idx, spv in ipairs(suppasp.main) do
-		local entry
 		if isasp and spv == isasp.main then
 			selid = idx
 		end
-		if spv == 0 then
-			entry = attrans("Danger (halt)")
-		elseif spv == -1 then
-			entry = attrans("Continue at maximum speed")
-		elseif not spv then
-			entry = attrans("Continue with current speed limit")
-		else
-			entry = attrans("Continue with the speed limit of @1", spv)
-		end
-		entries[idx] = entry
+		entries[idx] = describe_t1_main_aspect(spv)
 	end
-	form[#form+1] = F.dropdown(0.5, 2, 6, "main", entries, selid, true)
+	t.main = entries
+	t.main_current = selid
 
-	form[#form+1] = F.S_label(0.5, 3, "Shunt aspect")
 	if suppasp.shunt == nil then
-		local st = 1
-		if isasp and isasp.shunt then st = 2 end
-		local entries = {
-			attrans("No shunting"),
-			attrans("Shunting allowed"),
+		selid = 1
+		if isasp and isasp.shunt then
+			selid = 2
+		end
+		entries = {
+			describe_t1_shunt_aspect(false),
+			describe_t1_shunt_aspect(true),
 		}
-		form[#form+1] = F.dropdown(0.5, 3.5, 6, "shunt_free", entries, st, true)
+		t.shunt = entries
+		t.shunt_current = selid
 	end
 
-	form[#form+1] = F.S_label(0.5, 4.5, "Distant aspect")
-	local entries = {}
-	local selid = 1
+	entries = {}
+	selid = 1
 	for idx, spv in ipairs(suppasp.dst) do
-		local entry
 		if isasp and spv == isasp.dst then
 			selid = idx
 		end
-		if spv == 0 then
-			entry = attrans("Expect to stop at the next signal")
-		elseif spv == -1 then
-			entry = attrans("Expect to continue at maximum speed")
-		elseif not spv then
-			entry = attrans("No information on distant signal")
-		else
-			entry = attrans("Expect to continue with a speed limit of @1", spv)
-		end
-		entries[idx] = entry
+		entries[idx] = describe_t1_distant_aspect(spv)
 	end
-	form[#form+1] = F.dropdown(0.5, 5, 6, "dst", entries, selid, true)
+	t.dst = entries
+	t.dst_current = selid
+	return t
+end
+
+advtrains.interlocking.describe_supported_aspects_t1 = describe_supported_aspects_t1
+
+local signal_tabheader_map = {}
+
+local function make_signal_formspec_tabheader(pname, pos, width, selid)
+	signal_tabheader_map[pname] = pos
+	local options = {
+		attrans("Signal aspect"),
+		attrans("Influence point"),
+		attrans("Distant signalling"),
+	}
+	return F.tabheader(0, 0, nil, nil, "signal_tab", options, selid)
+end
+
+local function handle_signal_formspec_tabheader_fields(pname, fields)
+	local n = tonumber(fields.signal_tab)
+	local pos = signal_tabheader_map[pname]
+	if not (n and pos) then
+		return false
+	end
+	if n == 1 then
+		local node = advtrains.ndb.get_node(pos)
+		advtrains.interlocking.show_signal_form(pos, node, pname)
+	elseif n == 2 then
+		advtrains.interlocking.show_ip_form(pos, pname)
+	end
+	return true
+end
+
+advtrains.interlocking.make_signal_formspec_tabheader = make_signal_formspec_tabheader
+advtrains.interlocking.handle_signal_formspec_tabheader_fields = handle_signal_formspec_tabheader_fields
+
+local function make_signal_aspect_selector_t1(suppasp, purpose, isasp)
+	local form = {"size[7,7.25]"}
+	local t = describe_supported_aspects_t1(suppasp, isasp)
+	if type(purpose) == "table" then
+		form[#form+1] = make_signal_formspec_tabheader(purpose.pname, purpose.pos, 7, 1)
+		purpose = ""
+	end
+	form[#form+1] = F.S_label(0.5, 0.5, "Select signal aspect")
+	form[#form+1] = F.label(0.5, 1, purpose)
+
+	form[#form+1] = F.S_label(0.5, 1.5, "Main aspect")
+	form[#form+1] = F.dropdown(0.5, 2, 6, "main", t.main, t.main_current, true)
+
+	form[#form+1] = F.S_label(0.5, 3, "Shunt aspect")
+	if t.shunt then
+		form[#form+1] = F.dropdown(0.5, 3.5, 6, "shunt_free", t.shunt, t.shunt_current, true)
+	else
+		form[#form+1] = F.S_label(0.5, 3.5, "The shunt aspect cannot be changed")
+	end
+
+	form[#form+1] = F.S_label(0.5, 4.5, "Distant aspect")
+	form[#form+1] = F.dropdown(0.5, 5, 6, "dst", t.dst, t.dst_current, true)
 
 	form[#form+1] = F.S_button_exit(0.5, 6, 6, 1, "save", "Save signal aspect")
 	return table.concat(form)
@@ -69,6 +142,10 @@ local function make_signal_aspect_selector_t2(suppasp, purpose, isasp)
 	if not def then
 		return nil
 	end
+	if type(purpose) == "table" then
+		form[#form+1] = make_signal_formspec_tabheader(purpose.pname, purpose.pos, 7, 1)
+		purpose = ""
+	end
 	form[#form+1] = F.S_label(0.5, 0.5, "Select signal aspect")
 	form[#form+1] = F.label(0.5, 1, purpose)
 
@@ -93,6 +170,9 @@ function advtrains.interlocking.show_signal_aspect_selector(pname, p_suppasp, p_
 		info = {},
 	}
 	local purpose = p_purpose or ""
+	if type(p_purpose) == "table" then
+		purpose = {pname = pname, pos = p_purpose}
+	end
 
 	local form
 	if suppasp.type == 2 then
@@ -106,13 +186,13 @@ function advtrains.interlocking.show_signal_aspect_selector(pname, p_suppasp, p_
 
 	local token = advtrains.random_id()
 	minetest.show_formspec(pname, "at_il_sigaspdia_"..token, form)
-	minetest.after(1, function()
+	--minetest.after(1, function()
 	players_aspsel[pname] = {
 		suppasp = suppasp,
 		callback = callback,
 		token = token,
 	}
-	end)
+	--end)
 end
 
 local function usebool(sup, val, free)
@@ -147,6 +227,9 @@ minetest.register_on_player_receive_fields(function(player, formname, fields)
 	if psl then
 		if formname == "at_il_sigaspdia_"..psl.token then
 			local suppasp = psl.suppasp
+			if handle_signal_formspec_tabheader_fields(pname, fields) then
+				return true
+			end
 			if fields.save then
 				local asp
 				if suppasp.type == 2 then
diff --git a/advtrains_interlocking/signal_aspects.lua b/advtrains_interlocking/signal_aspects.lua
index a70d176..eebb4ba 100644
--- a/advtrains_interlocking/signal_aspects.lua
+++ b/advtrains_interlocking/signal_aspects.lua
@@ -1,4 +1,4 @@
-type2defs = {}
+local type2defs = {}
 
 local function register_type2(def)
 	local t = {type = 2}
diff --git a/advtrains_interlocking/signal_main_ui.lua b/advtrains_interlocking/signal_main_ui.lua
new file mode 100644
index 0000000..e69de29
diff --git a/advtrains_interlocking/spec/signal_api_spec.lua b/advtrains_interlocking/spec/signal_api_spec.lua
index 2659380..cd7a1d1 100644
--- a/advtrains_interlocking/spec/signal_api_spec.lua
+++ b/advtrains_interlocking/spec/signal_api_spec.lua
@@ -4,8 +4,7 @@ mineunit("core")
 
 _G.advtrains = {
 	interlocking = {
-		aspects = sourcefile("signal_aspects"),
-		--aspects = fixture("../../signal_aspects"),
+		aspects = fixture("../../signal_aspects"),
 	},
 	ndb = {
 		get_node = minetest.get_node,
diff --git a/advtrains_interlocking/tcb_ts_ui.lua b/advtrains_interlocking/tcb_ts_ui.lua
index 0cc10da..b3b8221 100755
--- a/advtrains_interlocking/tcb_ts_ui.lua
+++ b/advtrains_interlocking/tcb_ts_ui.lua
@@ -608,7 +608,8 @@ function advtrains.interlocking.show_signalling_form(sigd, pname, sel_rte, calle
 	if not tcbs.signal_name then tcbs.signal_name = "Signal at "..minetest.pos_to_string(sigd.p) end
 	if not tcbs.routes then tcbs.routes = {} end
 	
-	local form = "size[7,10]label[0.5,0.5;Signal at "..minetest.pos_to_string(sigd.p).."]"
+	local form = "size[7,9.75]label[0.5,0.5;Signal at "..minetest.pos_to_string(sigd.p).."]"
+	form = form .. advtrains.interlocking.make_signal_formspec_tabheader(pname, tcbs.signal, 7, 1)
 	form = form.."field[0.8,1.5;5.2,1;name;Signal name;"..minetest.formspec_escape(tcbs.signal_name).."]"
 	form = form.."button[5.5,1.2;1,1;setname;Set]"
 	
@@ -668,12 +669,7 @@ function advtrains.interlocking.show_signalling_form(sigd, pname, sel_rte, calle
 			if hasprivs then
 				form = form.."button[0.5,8;2.5,1;newroute;New Route]"
 				form = form.."button[  3,8;2.5,1;unassign;Unassign Signal]"
-				form = form.."button[  3,9;2.5,1;influp;Influence Point]"
-			end
-			if tcbs.ars_disabled then
-				form = form.."button[0.5,9;2.5,1;arsenable;Enable ARS]"
-			else
-				form = form.."button[0.5,9;2.5,1;arsdisable;Disable ARS]"
+				form = form..string.format("checkbox[0.5,8.75;ars;Automatic routesetting;%s]", not tcbs.ars_disabled)
 			end
 		elseif sigd_equal(tcbs.route_origin, sigd) then
 			-- something has gone wrong: tcbs.routeset should have been set...
@@ -706,6 +702,10 @@ end
 
 minetest.register_on_player_receive_fields(function(player, formname, fields)
 	local pname = player:get_player_name()
+	if string.find(formname, "^at_il_signalling_")
+		and advtrains.interlocking.handle_signal_formspec_tabheader_fields(pname, fields) then
+		return true
+	end
 	if not minetest.check_player_privs(pname, "train_operator") then
 		return
 	end
@@ -792,16 +792,9 @@ minetest.register_on_player_receive_fields(function(player, formname, fields)
 				minetest.chat_send_player(pname, "Please cancel route first!")
 			end
 		end
-		if fields.influp and hasprivs then
-			advtrains.interlocking.show_ip_form(tcbs.signal, pname)
-			return
-		end
 		
-		if tcbs.ars_disabled and fields.arsenable then
-			tcbs.ars_disabled = nil
-		end
-		if not tcbs.ars_disabled and fields.arsdisable then
-			tcbs.ars_disabled = true
+		if fields.ars then
+			tcbs.ars_disabled = not minetest.is_yes(fields.ars)
 		end
 		
 		if fields.auto then
-- 
cgit v1.2.3


From 98c37108762c6d7c9f1d691b84f49bfa65b81b28 Mon Sep 17 00:00:00 2001
From: "Y. Wang" <yw05@forksworld.de>
Date: Sat, 11 Jun 2022 18:07:00 +0200
Subject: Implement primitive distant signaling

---
 advtrains/formspec.lua                             |  10 ++
 advtrains_interlocking/database.lua                |   4 +
 advtrains_interlocking/demosignals.lua             |   6 +-
 advtrains_interlocking/distant.lua                 | 137 +++++++++++++++++++++
 advtrains_interlocking/distant_ui.lua              |  76 ++++++++++++
 advtrains_interlocking/init.lua                    |   3 +
 advtrains_interlocking/routesetting.lua            |  21 ++++
 advtrains_interlocking/signal_api.lua              |  85 +------------
 advtrains_interlocking/signal_aspect_accessors.lua | 127 +++++++++++++++++++
 advtrains_interlocking/signal_aspect_ui.lua        |   6 +-
 advtrains_interlocking/signal_aspects.lua          |  26 +++-
 advtrains_interlocking/signal_main_ui.lua          |   0
 .../spec/basic_signalling_spec.lua                 |  87 +++++++++++++
 advtrains_interlocking/spec/signal_api_spec.lua    |  49 --------
 advtrains_interlocking/tcb_ts_ui.lua               |   8 +-
 15 files changed, 507 insertions(+), 138 deletions(-)
 create mode 100644 advtrains_interlocking/distant.lua
 create mode 100644 advtrains_interlocking/distant_ui.lua
 create mode 100644 advtrains_interlocking/signal_aspect_accessors.lua
 delete mode 100644 advtrains_interlocking/signal_main_ui.lua
 create mode 100644 advtrains_interlocking/spec/basic_signalling_spec.lua
 delete mode 100644 advtrains_interlocking/spec/signal_api_spec.lua

(limited to 'advtrains_interlocking/spec')

diff --git a/advtrains/formspec.lua b/advtrains/formspec.lua
index aa5aa69..20dab59 100644
--- a/advtrains/formspec.lua
+++ b/advtrains/formspec.lua
@@ -9,6 +9,14 @@ local function make_list(entries)
 	return table.concat(t, ",")
 end
 
+local function f_button(x, y, w, h, id, text)
+	return sformat("button[%f,%f;%f,%f;%s;%s]", x, y, w, h, id, text)
+end
+
+local function S_button(x, y, w, h, id, ...)
+	return f_button(x, y, w, h, id, attrans(...))
+end
+
 local function f_button_exit(x, y, w, h, id, text)
 	return sformat("button_exit[%f,%f;%f,%f;%s;%s]", x, y, w, h, id, text)
 end
@@ -54,6 +62,8 @@ local function f_tabheader(x, y, w, h, id, entries, sel, transparent, border)
 end
 
 return {
+	button = f_button,
+	S_button = S_button,
 	button_exit = f_button_exit,
 	S_button_exit = S_button_exit,
 	dropdown = f_dropdown,
diff --git a/advtrains_interlocking/database.lua b/advtrains_interlocking/database.lua
index efa5eb8..c5ae906 100644
--- a/advtrains_interlocking/database.lua
+++ b/advtrains_interlocking/database.lua
@@ -134,6 +134,9 @@ function ildb.load(data)
 	if data.supposed_aspects then
 		advtrains.interlocking.load_supposed_aspects(data.supposed_aspects)
 	end
+	if data.distant then
+		advtrains.distant.load(data.distant)
+	end
 	
 	--COMPATIBILITY to Signal aspect format
 	-- TODO remove in time...
@@ -177,6 +180,7 @@ function ildb.save()
 		influence_points = influence_points,
 		npr_rails = advtrains.interlocking.npr_rails,
 		supposed_aspects = advtrains.interlocking.save_supposed_aspects(),
+		distant = advtrains.distant.save(),
 	}
 end
 
diff --git a/advtrains_interlocking/demosignals.lua b/advtrains_interlocking/demosignals.lua
index 1c1b8b2..de6926a 100644
--- a/advtrains_interlocking/demosignals.lua
+++ b/advtrains_interlocking/demosignals.lua
@@ -50,7 +50,7 @@ minetest.register_node("advtrains_interlocking:ds_danger", {
 	},
 	on_rightclick = advtrains.interlocking.signal_rc_handler,
 	can_dig = advtrains.interlocking.signal_can_dig,
-	after_dig_node = advtrains.interlocking.signal_after_dig,
+	after_destruct = advtrains.interlocking.signal_after_dig,
 })
 minetest.register_node("advtrains_interlocking:ds_free", {
 	description = "Demo signal at Free",
@@ -71,7 +71,7 @@ minetest.register_node("advtrains_interlocking:ds_free", {
 	},
 	on_rightclick = advtrains.interlocking.signal_rc_handler,
 	can_dig = advtrains.interlocking.signal_can_dig,
-	after_dig_node = advtrains.interlocking.signal_after_dig,
+	after_destruct = advtrains.interlocking.signal_after_dig,
 })
 minetest.register_node("advtrains_interlocking:ds_slow", {
 	description = "Demo signal at Slow",
@@ -92,6 +92,6 @@ minetest.register_node("advtrains_interlocking:ds_slow", {
 	},
 	on_rightclick = advtrains.interlocking.signal_rc_handler,
 	can_dig = advtrains.interlocking.signal_can_dig,
-	after_dig_node = advtrains.interlocking.signal_after_dig,
+	after_destruct = advtrains.interlocking.signal_after_dig,
 })
 
diff --git a/advtrains_interlocking/distant.lua b/advtrains_interlocking/distant.lua
new file mode 100644
index 0000000..ffa9e08
--- /dev/null
+++ b/advtrains_interlocking/distant.lua
@@ -0,0 +1,137 @@
+local db_distant = {}
+local db_distant_of = {}
+
+local A = advtrains.interlocking.aspects
+local pts = advtrains.encode_pos
+local stp = advtrains.decode_pos
+
+local function db_load(x)
+	if type(x) ~= "table" then
+		return
+	end
+	db_distant = x.distant
+	db_distant_of = x.distant_of
+end
+
+local function db_save()
+	return {
+		distant = db_distant,
+		distant_of = db_distant_of,
+	}
+end
+
+local update_signal, update_main, update_dst
+
+local function unassign_dst(dst, force)
+	local pts_dst = pts(dst)
+	local main = db_distant_of[pts_dst]
+	db_distant_of[pts_dst] = nil
+	if main then
+		local pts_main = main[1]
+		local t = db_distant[pts_main]
+		if t then
+			t[pts_dst] = nil
+		end
+	end
+	if not force then
+		update_dst(dst)
+	end
+end
+
+local function unassign_main(main, force)
+	local pts_main = pts(main)
+	local t = db_distant[pts_main]
+	if not t then
+		return
+	end
+	for pts_dst in pairs(t) do
+		local realmain = db_distant_of[pts_dst]
+		if realmain and realmain[1] == pts_main then
+			db_distant_of[pts_dst] = nil
+			if not force then
+				local dst = stp(pts_dst)
+				update_dst(dst)
+			end
+		end
+	end
+	db_distant[pts_main] = nil
+end
+
+local function unassign_all(pos, force)
+	unassign_main(pos)
+	unassign_dst(pos, force)
+end
+
+local function assign(main, dst, by)
+	local pts_main = pts(main)
+	local pts_dst = pts(dst)
+	local t = db_distant[pts_main]
+	if not t then
+		t = {}
+		db_distant[pts_main] = t
+	end
+	if not by then
+		by = "manual"
+	end
+	unassign_dst(dst, true)
+	t[pts_dst] = by
+	db_distant_of[pts_dst] = {pts_main, by}
+	update_dst(dst)
+end
+
+local function pre_occupy(dst, by)
+	local pts_dst = pts(dst)
+	unassign_dst(dst)
+	db_distant_of[pts_dst] = {nil, by}
+end
+
+local function get_distant(main)
+	local pts_main = pts(main)
+	return db_distant[pts_main] or {}
+end
+
+local function get_main(dst)
+	local pts_dst = pts(dst)
+	local main = db_distant_of[pts_dst]
+	if not main then
+		return
+	end
+	if main[1] then
+		return stp(main[1]), unpack(main, 2)
+	else
+		return unpack(main)
+	end
+end
+
+update_main = function(main)
+	local pts_main = pts(main)
+	local t = get_distant(main)
+	for pts_dst in pairs(t) do
+		local dst = stp(pts_dst)
+		advtrains.interlocking.signal_readjust_aspect(dst)
+	end
+end
+
+update_dst = function(dst)
+	advtrains.interlocking.signal_readjust_aspect(dst)
+end
+
+update_signal = function(pos)
+	update_main(pos)
+	update_dst(pos)
+end
+
+advtrains.distant = {
+	load = db_load,
+	save = db_save,
+	assign = assign,
+	unassign_dst = unassign_dst,
+	unassign_main = unassign_main,
+	unassign_all = unassign_all,
+	get_distant = get_distant,
+	get_dst = get_distant,
+	get_main = get_main,
+	update_main = update_main,
+	update_dst = update_dst,
+	update_signal = update_signal,
+}
diff --git a/advtrains_interlocking/distant_ui.lua b/advtrains_interlocking/distant_ui.lua
new file mode 100644
index 0000000..4ec2255
--- /dev/null
+++ b/advtrains_interlocking/distant_ui.lua
@@ -0,0 +1,76 @@
+local F = advtrains.formspec
+local D = advtrains.distant
+local I = advtrains.interlocking
+
+function advtrains.interlocking.show_distant_signal_form(pos, pname)
+	local form = {"size[7,7]"}
+	form[#form+1] = advtrains.interlocking.make_signal_formspec_tabheader(pname, pos, 7, 3)
+	local main, set_by = D.get_main(pos)
+	if main then
+		local pts_main = minetest.pos_to_string(main)
+		form[#form+1] = F.S_label(0.5, 0.5, "This signal is a distant signal of @1.", pts_main)
+		if set_by == "manual" then
+			form[#form+1] = F.S_label(0.5, 1, "The assignment is made manually.")
+		elseif set_by == "routesetting" then
+			form[#form+1] = F.S_label(0.5, 1, "The assignment is made by the routesetting system.")
+		end
+	else
+		form[#form+1] = F.S_label(0.5, 0.5, "This signal is not assigned to a main signal.")
+		form[#form+1] = F.S_label(0.5, 1, "The distant aspect of the signal is not used.")
+	end
+	if set_by ~= nil then
+		form[#form+1] = F.S_button_exit(0.5, 1.5, 3, 1, "unassign_dst", "Unassign")
+		form[#form+1] = F.S_button_exit(3.5, 1.5, 3, 1, "assign_dst", "Reassign")
+	else
+		form[#form+1] = F.S_button_exit(0.5, 1.5, 6, 1, "assign_dst", "Assign")
+	end
+	minetest.show_formspec(pname, "advtrains:distant_" .. minetest.pos_to_string(pos), table.concat(form))
+end
+
+local signal_pos = {}
+local function init_signal_assignment(pname, pos)
+	if not minetest.check_player_privs(pname, "interlocking") then
+		minetest.chat_send_player(pname, attrans("This operation is not allowed without the @1 privilege.", "interlocking"))
+		return
+	end
+	signal_pos[pname] = pos
+	minetest.chat_send_player(pname, attrans("Please punch the signal to use as the main signal."))
+end
+
+minetest.register_on_punchnode(function(pos, node, player, pointed_thing)
+	local pname = player:get_player_name()
+	if not minetest.check_player_privs(pname, "interlocking") then
+		return
+	end
+	local spos = signal_pos[pname]
+	if not spos then
+		return
+	end
+	signal_pos[pname] = nil
+	local is_signal = minetest.get_item_group(node.name, "advtrains_signal") >= 2
+	if not is_signal then
+		minetest.chat_send_player(pname, attrans("Incompatible signal."))
+		return
+	end
+	minetest.chat_send_player(pname, attrans("Successfully assigned signal."))
+	D.assign(pos, spos, "manual")
+end)
+
+minetest.register_on_player_receive_fields(function(player, formname, fields)
+	local pname = player:get_player_name()
+	local pos = minetest.string_to_pos(string.match(formname, "^advtrains:distant_(.+)$") or "")
+	if not pos then
+		return
+	end
+	if not minetest.check_player_privs(pname, "interlocking") then
+		return
+	end
+	if advtrains.interlocking.handle_signal_formspec_tabheader_fields(pname, fields) then
+		return true
+	end
+	if fields.unassign_dst then
+		D.unassign_dst(pos)
+	elseif fields.assign_dst then
+		init_signal_assignment(pname, pos)
+	end
+end)
diff --git a/advtrains_interlocking/init.lua b/advtrains_interlocking/init.lua
index d0b75a8..908d998 100644
--- a/advtrains_interlocking/init.lua
+++ b/advtrains_interlocking/init.lua
@@ -15,6 +15,9 @@ local modpath = minetest.get_modpath(minetest.get_current_modname()) .. DIR_DELI
 advtrains.interlocking.aspects = dofile(modpath.."signal_aspects.lua")
 
 dofile(modpath.."database.lua")
+dofile(modpath.."distant.lua")
+dofile(modpath.."distant_ui.lua")
+dofile(modpath.."signal_aspect_accessors.lua")
 dofile(modpath.."signal_api.lua")
 dofile(modpath.."signal_aspect_ui.lua")
 dofile(modpath.."demosignals.lua")
diff --git a/advtrains_interlocking/routesetting.lua b/advtrains_interlocking/routesetting.lua
index 67efaea..f1b4455 100644
--- a/advtrains_interlocking/routesetting.lua
+++ b/advtrains_interlocking/routesetting.lua
@@ -45,6 +45,7 @@ function ilrs.set_route(signal, route, try)
 	local rtename = route.name
 	local signalname = ildb.get_tcbs(signal).signal_name
 	local c_tcbs, c_ts_id, c_ts, c_rseg, c_lckp
+	local signals = {}
 	while c_sigd and i<=#route do
 		c_tcbs = ildb.get_tcbs(c_sigd)
 		if not c_tcbs then
@@ -115,6 +116,7 @@ function ilrs.set_route(signal, route, try)
 				c_tcbs.aspect = route.aspect or advtrains.interlocking.GENERIC_FREE
 				c_tcbs.route_origin = signal
 				advtrains.interlocking.update_signal_aspect(c_tcbs)
+				signals[#signals+1] = c_tcbs.signal
 			end
 		end
 		-- advance
@@ -122,6 +124,25 @@ function ilrs.set_route(signal, route, try)
 		c_sigd = c_rseg.next
 		i = i + 1
 	end
+
+	-- Distant signaling
+	local lastsig = nil
+	if c_sigd then
+		local e_tcbs = ildb.get_tcbs(c_sigd)
+		local pos = e_tcbs and e_tcbs.signal
+		if pos then
+			lastsig = pos
+		end
+	end
+	for i = #signals, 1, -1 do
+		if lastsig then
+			local pos = signals[i]
+			local _, assigned_by = advtrains.distant.get_main(pos)
+			if assigned_by ~= "manual" then
+				advtrains.distant.assign(lastsig, signals[i], "routesetting")
+			end
+		end
+	end
 	
 	return true
 end
diff --git a/advtrains_interlocking/signal_api.lua b/advtrains_interlocking/signal_api.lua
index 5b3baf8..1fd4e34 100644
--- a/advtrains_interlocking/signal_api.lua
+++ b/advtrains_interlocking/signal_api.lua
@@ -167,7 +167,6 @@ This function will query get_aspect to retrieve the new aspect.
 
 local DANGER = {
 	main = 0,
-	dst = false,
 	shunt = false,
 }
 advtrains.interlocking.DANGER = DANGER
@@ -178,8 +177,6 @@ advtrains.interlocking.GENERIC_FREE = {
 	dst = false,
 }
 
-local supposed_aspects = {}
-
 local function convert_aspect_if_necessary(asp)
 	if type(asp.main) == "table" then
 		local newasp = {} 
@@ -200,24 +197,7 @@ local function convert_aspect_if_necessary(asp)
 	end
 	return asp
 end
-
-function advtrains.interlocking.load_supposed_aspects(tbl)
-	if tbl then
-		supposed_aspects = tbl
-	end
-end
-
-function advtrains.interlocking.save_supposed_aspects()
-	return supposed_aspects
-end
-
-local function set_supposed_aspect(pos, asp)
-	supposed_aspects[advtrains.roundfloorpts(pos)] = asp
-end
-
-local function get_supposed_aspect(pos)
-	return supposed_aspects[advtrains.roundfloorpts(pos)]
-end
+advtrains.interlocking.signal_convert_aspect_if_necessary = convert_aspect_if_necessary
 
 function advtrains.interlocking.update_signal_aspect(tcbs)
 	if tcbs.signal then
@@ -233,27 +213,8 @@ end
 function advtrains.interlocking.signal_after_dig(pos)
 	-- clear influence point
 	advtrains.interlocking.db.clear_ip_by_signalpos(pos)
-	set_supposed_aspect(pos, nil)
-end
-
-function advtrains.interlocking.signal_set_aspect(pos, asp)
-	asp = convert_aspect_if_necessary(asp)
-	local node=advtrains.ndb.get_node(pos)
-	local ndef=minetest.registered_nodes[node.name]
-	if ndef and ndef.advtrains and ndef.advtrains.set_aspect then
-		local oldasp = advtrains.interlocking.signal_get_aspect(pos) or DANGER
-		local suppasp = advtrains.interlocking.signal_get_supported_aspects(pos) or {}
-		local newasp = asp
-		if suppasp.type == 2 then
-			asp = advtrains.interlocking.aspects.type1_to_type2main(asp, suppasp.group)
-		end
-		set_supposed_aspect(pos, newasp)
-		ndef.advtrains.set_aspect(pos, node, asp)
-		local aspect_changed = advtrains.interlocking.aspects.not_equalp(oldasp, newasp)
-		if aspect_changed then
-			advtrains.interlocking.signal_on_aspect_changed(pos)
-		end
-	end
+	advtrains.interlocking.signal_clear_aspect(pos)
+	advtrains.distant.unassign_all(pos, true)
 end
 
 -- should be called when aspect has changed on this signal.
@@ -312,46 +273,6 @@ function advtrains.interlocking.signal_get_supposed_aspect(pos)
 	return DANGER;
 end
 
--- Returns the actual aspect of the signal at position, as returned by the nodedef.
--- returns nil when there's no signal at the position
-function advtrains.interlocking.signal_get_real_aspect(pos)
-	local node=advtrains.ndb.get_node(pos)
-	local ndef=minetest.registered_nodes[node.name]
-	if ndef and ndef.advtrains and ndef.advtrains.get_aspect then
-		local asp = ndef.advtrains.get_aspect(pos, node)
-		local suppasp = advtrains.interlocking.signal_get_supported_aspects(pos) or {}
-		if suppasp.type == 2 then
-			asp = advtrains.interlocking.aspects.type2main_to_type1(suppasp.group, asp)
-		end
-		if not asp then asp = DANGER end
-		asp = convert_aspect_if_necessary(asp)
-		return asp
-	end
-	return nil
-end
-
--- Returns the signal aspect as reported in the suppasp table.
-function advtrains.interlocking.signal_get_aspect(pos)
-	local asp = get_supposed_aspect(pos)
-	if not asp then
-		asp = advtrains.interlocking.signal_get_real_aspect(pos)
-		set_supposed_aspect(pos, asp)
-	end
-	return asp
-end
-
--- Returns the "supported_aspects" of the signal at position, as returned by the nodedef.
--- returns nil when there's no signal at the position
-function advtrains.interlocking.signal_get_supported_aspects(pos)
-	local node=advtrains.ndb.get_node(pos)
-	local ndef=minetest.registered_nodes[node.name]
-	if ndef and ndef.advtrains and ndef.advtrains.supported_aspects then
-		local asp = ndef.advtrains.supported_aspects
-		return asp
-	end
-	return nil
-end
-
 local players_assign_ip = {}
 
 local function ipmarker(ipos, connid)
diff --git a/advtrains_interlocking/signal_aspect_accessors.lua b/advtrains_interlocking/signal_aspect_accessors.lua
new file mode 100644
index 0000000..02a03ea
--- /dev/null
+++ b/advtrains_interlocking/signal_aspect_accessors.lua
@@ -0,0 +1,127 @@
+local A = advtrains.interlocking.aspects
+local D = advtrains.distant
+local I = advtrains.interlocking
+local N = advtrains.ndb
+local pts = advtrains.roundfloorpts
+
+local get_aspect
+
+local supposed_aspects = {}
+
+function I.load_supposed_aspects(tbl)
+	if tbl then
+		supposed_aspects = tbl
+	end
+end
+
+function I.save_supposed_aspects()
+	return supposed_aspects
+end
+
+local function get_supposed_aspect(pos)
+	return supposed_aspects[pts(pos)]
+end
+
+local function set_supposed_aspect(pos, asp)
+	supposed_aspects[pts(pos)] = asp
+end
+
+local function get_ndef(pos)
+	local node = N.get_node(pos)
+	return minetest.registered_nodes[node.name] or {}
+end
+
+local function get_supported_aspects(pos)
+	local ndef = get_ndef(pos)
+	if ndef.advtrains and ndef.advtrains.supported_aspects then
+		return ndef.advtrains.supported_aspects
+	end
+	return nil
+end
+
+local function adjust_aspect(pos, asp)
+	asp = table.copy(I.signal_convert_aspect_if_necessary(asp))
+
+	local mainpos = D.get_main(pos)
+	local nxtasp
+	if asp.main ~= 0 and mainpos then
+		nxtasp = get_aspect(mainpos)
+		asp.dst = nxtasp.main
+	else
+		asp.dst = nil
+	end
+
+	local suppasp = get_supported_aspects(pos)
+	if not suppasp then
+		return asp, asp
+	end
+	local stype = suppasp.type
+	if stype == 2 then
+		local group = suppasp.group
+		local name
+		if asp.main ~= 0 and nxtasp and nxtasp.type2group == group and nxtasp.type2name then
+			name = A.get_type2_dst(group, nxtasp.type2name)
+		else
+			name = A.type1_to_type2main(asp, group)
+		end
+		asp.type2group = group
+		asp.type2name = name
+		return asp, name
+	end
+	asp.type2name = nil
+	asp.type2group = nil
+	return asp, asp
+end
+
+local function get_real_aspect(pos)
+	local ndef = get_ndef(pos)
+	if ndef.advtrains and ndef.advtrains.get_aspect then
+		local asp = ndef.advtrains.get_aspect(pos, node) or I.DANGER
+		local suppasp = get_supported_aspects(pos)
+		if suppasp.type == 2 then
+			asp = A.type2main_to_type1(suppasp.group, asp)
+		end
+		return adjust_aspect(pos, asp)
+	end
+	return nil
+end
+
+get_aspect = function(pos)
+	local asp = get_supposed_aspect(pos)
+	if not asp then
+		asp = get_real_aspect(pos)
+		set_supposed_aspect(pos, asp)
+	end
+	return asp
+end
+
+local function set_aspect(pos, asp)
+	local node = N.get_node(pos)
+	local ndef = minetest.registered_nodes[node.name]
+	if ndef and ndef.advtrains and ndef.advtrains.set_aspect then
+		local oldasp = I.signal_get_aspect(pos) or DANGER
+		local newasp, aspval = adjust_aspect(pos, asp)
+		set_supposed_aspect(pos, newasp)
+		ndef.advtrains.set_aspect(pos, node, aspval)
+		local aspect_changed = A.not_equalp(oldasp, newasp)
+		if aspect_changed then
+			I.signal_on_aspect_changed(pos)
+			D.update_main(pos)
+		end
+	end
+end
+
+local function clear_aspect(pos)
+	set_supposed_aspect(pos, nil)
+end
+
+local function readjust_aspect(pos)
+	set_aspect(pos, get_aspect(pos))
+end
+
+I.signal_get_supported_aspects = get_supported_aspects
+I.signal_get_real_aspect = get_real_aspect
+I.signal_get_aspect = get_aspect
+I.signal_set_aspect = set_aspect
+I.signal_clear_aspect = clear_aspect
+I.signal_readjust_aspect = readjust_aspect
diff --git a/advtrains_interlocking/signal_aspect_ui.lua b/advtrains_interlocking/signal_aspect_ui.lua
index 4b41187..30b5165 100644
--- a/advtrains_interlocking/signal_aspect_ui.lua
+++ b/advtrains_interlocking/signal_aspect_ui.lua
@@ -43,7 +43,7 @@ local function describe_supported_aspects_t1(suppasp, isasp)
 	local entries = {}
 	local selid = 1
 	for idx, spv in ipairs(suppasp.main) do
-		if isasp and spv == isasp.main then
+		if isasp and spv == (isasp.main or false) then
 			selid = idx
 		end
 		entries[idx] = describe_t1_main_aspect(spv)
@@ -67,7 +67,7 @@ local function describe_supported_aspects_t1(suppasp, isasp)
 	entries = {}
 	selid = 1
 	for idx, spv in ipairs(suppasp.dst) do
-		if isasp and spv == isasp.dst then
+		if isasp and spv == (isasp.dst or false) then
 			selid = idx
 		end
 		entries[idx] = describe_t1_distant_aspect(spv)
@@ -102,6 +102,8 @@ local function handle_signal_formspec_tabheader_fields(pname, fields)
 		advtrains.interlocking.show_signal_form(pos, node, pname)
 	elseif n == 2 then
 		advtrains.interlocking.show_ip_form(pos, pname)
+	elseif n == 3 then
+		advtrains.interlocking.show_distant_signal_form(pos, pname)
 	end
 	return true
 end
diff --git a/advtrains_interlocking/signal_aspects.lua b/advtrains_interlocking/signal_aspects.lua
index eebb4ba..2866ae1 100644
--- a/advtrains_interlocking/signal_aspects.lua
+++ b/advtrains_interlocking/signal_aspects.lua
@@ -44,6 +44,27 @@ local function get_type2_definition(name)
 	return type2defs[name]
 end
 
+local function get_type2_danger(group)
+	local def = type2defs[group]
+	if not def then
+		return nil
+	end
+	local main = def.main
+	return main[#main]
+end
+
+local function get_type2_dst(group, name)
+	local def = type2defs[group]
+	if not def then
+		return nil
+	end
+	local aspidx = name
+	if type(name) ~= "number" then
+		aspidx = def.main[name] or 1
+	end
+	return def.main[math.max(1, aspidx-1)].name
+end
+
 local function type2main_to_type1(name, asp)
 	local def = type2defs[name]
 	if not def then
@@ -53,7 +74,7 @@ local function type2main_to_type1(name, asp)
 	if type(asp) == "number" then
 		aspidx = asp
 	else
-		aspidx = def.main[asp]
+		aspidx = def.main[asp] or 2
 	end
 	local asptbl = def.main[aspidx]
 	if not asptbl then
@@ -62,11 +83,13 @@ local function type2main_to_type1(name, asp)
 	if type(asp) == "number" then
 		asp = asptbl.name
 	end
+	local dst = def.main[math.min(#def.main, aspidx+1)].main
 
 	local t = {
 		main = asptbl.main,
 		type2name = asp,
 		type2group = name,
+		dst = dst,
 	}
 	if aspidx > 1 and aspidx < #asptbl then
 		t.dst = asptbl[aspidx+1].main
@@ -116,6 +139,7 @@ end
 return {
 	register_type2 = register_type2,
 	get_type2_definition = get_type2_definition,
+	get_type2_dst = get_type2_dst,
 	type2main_to_type1 = type2main_to_type1,
 	type1_to_type2main = type1_to_type2main,
 	equalp = equalp,
diff --git a/advtrains_interlocking/signal_main_ui.lua b/advtrains_interlocking/signal_main_ui.lua
deleted file mode 100644
index e69de29..0000000
diff --git a/advtrains_interlocking/spec/basic_signalling_spec.lua b/advtrains_interlocking/spec/basic_signalling_spec.lua
new file mode 100644
index 0000000..0b79972
--- /dev/null
+++ b/advtrains_interlocking/spec/basic_signalling_spec.lua
@@ -0,0 +1,87 @@
+--[[
+This file tests a large part of the signaling system, as a lot of tests for the
+signaling system tend to overlap for various parts of the system.
+]]
+
+require("mineunit")
+mineunit("core")
+
+_G.advtrains = {
+	interlocking = {
+		aspects = fixture("../../signal_aspects"),
+	},
+	ndb = {
+		get_node = minetest.get_node,
+		swap_node = minetest.swap_node,
+	}
+}
+
+fixture("advtrains_helpers")
+fixture("../../database")
+sourcefile("distant")
+sourcefile("signal_api")
+sourcefile("signal_aspect_accessors")
+fixture("../../demosignals")
+
+local D = advtrains.distant
+local I = advtrains.interlocking
+
+local stub_aspect_t1 = {
+	free = {main = -1},
+	slow = {main = 6},
+	danger = {main = 0, shunt = false},
+}
+local stub_pos_t1 = {}
+for i = 1, 3 do
+	stub_pos_t1[i] = {x = 1, y = 0, z = i}
+end
+
+world.layout {
+	{stub_pos_t1[1], "advtrains_interlocking:ds_danger"},
+	{stub_pos_t1[2], "advtrains_interlocking:ds_slow"},
+	{stub_pos_t1[3], "advtrains_interlocking:ds_free"},
+}
+
+describe("API for supposed signal aspects", function()
+	it("should load and save data properly", function()
+		local tbl = {_foo = true}
+		I.load_supposed_aspects(tbl)
+		assert.same(tbl, I.save_supposed_aspects())
+	end)
+	it("should set and get type 1 signals properly", function ()
+		local pos = stub_pos_t1[2]
+		local asp = stub_aspect_t1.slow
+		local newasp = { main = math.random(1,5) }
+		assert.same(asp, I.signal_get_aspect(pos))
+		I.signal_set_aspect(pos, newasp)
+		assert.same(newasp, I.signal_get_aspect(pos))
+		assert.same(asp, I.signal_get_real_aspect(pos))
+		I.signal_set_aspect(pos, asp)
+	end)
+end)
+
+describe("Distant signaling", function()
+	it("should assign distant signals and set the distant aspect correspondingly", function()
+		for i = 1, 2 do
+			D.assign(stub_pos_t1[i], stub_pos_t1[i+1])
+		end
+		assert.same(stub_aspect_t1.danger, I.signal_get_aspect(stub_pos_t1[1]))
+		assert.same({main = 6, dst = 0}, I.signal_get_aspect(stub_pos_t1[2]))
+		assert.same({main = -1, dst = 6}, I.signal_get_aspect(stub_pos_t1[3]))
+	end)
+	it("should report assignments properly", function()
+		assert.same({stub_pos_t1[1], "manual"}, {D.get_main(stub_pos_t1[2])})
+		assert.same({[advtrains.encode_pos(stub_pos_t1[3])] = "manual"}, D.get_dst(stub_pos_t1[2]))
+	end)
+	it("should update distant aspects automatically", function()
+		I.signal_set_aspect(stub_pos_t1[2], {main = 2, dst = -1})
+		assert.same({main = 2, dst = 0}, I.signal_get_aspect(stub_pos_t1[2]))
+		assert.same({main = -1, dst = 2}, I.signal_get_aspect(stub_pos_t1[3]))
+	end)
+	it("should unassign signals when one is removed", function()
+		world.set_node(stub_pos_t1[2], "air")
+		assert.same({}, D.get_dst(stub_pos_t1[1]))
+		assert.same({}, {D.get_main(stub_pos_t1[3])})
+		assert.same(stub_aspect_t1.free, I.signal_get_aspect(stub_pos_t1[3]))
+	end)
+end)
diff --git a/advtrains_interlocking/spec/signal_api_spec.lua b/advtrains_interlocking/spec/signal_api_spec.lua
deleted file mode 100644
index cd7a1d1..0000000
--- a/advtrains_interlocking/spec/signal_api_spec.lua
+++ /dev/null
@@ -1,49 +0,0 @@
-require("mineunit")
-
-mineunit("core")
-
-_G.advtrains = {
-	interlocking = {
-		aspects = fixture("../../signal_aspects"),
-	},
-	ndb = {
-		get_node = minetest.get_node,
-	}
-}
-
-fixture("advtrains_helpers")
-fixture("../../database")
-sourcefile("signal_api")
-
-local stub_aspect_t1 = { main = math.random() }
-local stub_pos_t1 = {x = 1, y = 0, z = 1}
-
-minetest.register_node(":stubsignal_t1", {
-	advtrains = {
-		supported_aspects = {},
-		get_aspect = function () return stub_aspect_t1 end,
-		set_aspect = function () end,
-	},
-	groups = { advtrains_signal = 2 },
-})
-
-world.layout {
-	{stub_pos_t1, "stubsignal_t1"},
-}
-
-describe("API for supposed signal aspects", function()
-	it("should load and save data properly", function()
-		local tbl = {_foo = true}
-		advtrains.interlocking.load_supposed_aspects(tbl)
-		assert.same(tbl, advtrains.interlocking.save_supposed_aspects())
-	end)
-	it("should set and get type 1 signals properly", function ()
-		local pos = stub_pos_t1
-		local asp = stub_aspect_t1
-		local newasp = { dst = math.random() }
-		assert.same(asp, advtrains.interlocking.signal_get_aspect(pos))
-		advtrains.interlocking.signal_set_aspect(pos, newasp)
-		assert.same(newasp, advtrains.interlocking.signal_get_aspect(pos))
-		assert.same(asp, advtrains.interlocking.signal_get_real_aspect(pos))
-	end)
-end)
diff --git a/advtrains_interlocking/tcb_ts_ui.lua b/advtrains_interlocking/tcb_ts_ui.lua
index b3b8221..9f88296 100755
--- a/advtrains_interlocking/tcb_ts_ui.lua
+++ b/advtrains_interlocking/tcb_ts_ui.lua
@@ -14,6 +14,7 @@ local lntrans = { "A", "B" }
 local function sigd_to_string(sigd)
 	return minetest.pos_to_string(sigd.p).." / "..lntrans[sigd.s]
 end
+advtrains.interlocking.sigd_to_string = sigd_to_string
 
 minetest.register_node("advtrains_interlocking:tcb_node", {
 	drawtype = "mesh",
@@ -608,7 +609,7 @@ function advtrains.interlocking.show_signalling_form(sigd, pname, sel_rte, calle
 	if not tcbs.signal_name then tcbs.signal_name = "Signal at "..minetest.pos_to_string(sigd.p) end
 	if not tcbs.routes then tcbs.routes = {} end
 	
-	local form = "size[7,9.75]label[0.5,0.5;Signal at "..minetest.pos_to_string(sigd.p).."]"
+	local form = "size[7,10.25]label[0.5,0.5;Signal at "..minetest.pos_to_string(sigd.p).."]"
 	form = form .. advtrains.interlocking.make_signal_formspec_tabheader(pname, tcbs.signal, 7, 1)
 	form = form.."field[0.8,1.5;5.2,1;name;Signal name;"..minetest.formspec_escape(tcbs.signal_name).."]"
 	form = form.."button[5.5,1.2;1,1;setname;Set]"
@@ -670,6 +671,7 @@ function advtrains.interlocking.show_signalling_form(sigd, pname, sel_rte, calle
 				form = form.."button[0.5,8;2.5,1;newroute;New Route]"
 				form = form.."button[  3,8;2.5,1;unassign;Unassign Signal]"
 				form = form..string.format("checkbox[0.5,8.75;ars;Automatic routesetting;%s]", not tcbs.ars_disabled)
+				form = form..string.format("checkbox[0.5,9.25;dst;Distant signalling;%s]", not tcbs.nodst)
 			end
 		elseif sigd_equal(tcbs.route_origin, sigd) then
 			-- something has gone wrong: tcbs.routeset should have been set...
@@ -796,6 +798,10 @@ minetest.register_on_player_receive_fields(function(player, formname, fields)
 		if fields.ars then
 			tcbs.ars_disabled = not minetest.is_yes(fields.ars)
 		end
+
+		if fields.dst then
+			tcbs.nodst = not minetest.is_yes(fields.dst)
+		end
 		
 		if fields.auto then
 			tcbs.route_auto = true
-- 
cgit v1.2.3


From 30a0f862488a0cb67f9a8e2aecaf17797ad44a93 Mon Sep 17 00:00:00 2001
From: "Y. Wang" <yw05@forksworld.de>
Date: Mon, 24 Oct 2022 13:51:03 +0200
Subject: Properly handle repeater signals

---
 advtrains_interlocking/signal_aspect_accessors.lua | 41 +++++++++++++++++-----
 advtrains_interlocking/signal_aspect_ui.lua        |  2 +-
 advtrains_interlocking/signal_aspects.lua          | 40 +++++++++++++--------
 .../spec/basic_signalling_spec.lua                 |  2 +-
 advtrains_interlocking/tcb_ts_ui.lua               | 28 ++++++++-------
 advtrains_signals_japan/init.lua                   |  1 +
 6 files changed, 77 insertions(+), 37 deletions(-)

(limited to 'advtrains_interlocking/spec')

diff --git a/advtrains_interlocking/signal_aspect_accessors.lua b/advtrains_interlocking/signal_aspect_accessors.lua
index a1cbd4e..060f923 100644
--- a/advtrains_interlocking/signal_aspect_accessors.lua
+++ b/advtrains_interlocking/signal_aspect_accessors.lua
@@ -4,6 +4,27 @@ local I = advtrains.interlocking
 local N = advtrains.ndb
 local pts = advtrains.roundfloorpts
 
+local signal_aspect_metatable = {
+	__tostring = function(asp)
+		local st = {}
+		if asp.type2group and asp.type2name then
+			table.insert(st, string.format("%q in group %q", asp.type2name, asp.type2group))
+		end
+		if asp.main then
+			table.insert(st, string.format("current %d", asp.main))
+		end
+		if asp.main ~= 0 then
+			if asp.dst then
+				table.insert(st, string.format("next %d", asp.dst))
+			end
+			if asp.proceed_as_main then
+				table.insert(st, "proceed as main")
+			end
+		end
+		return string.format("[%s]", table.concat(st, ", "))
+	end,
+}
+
 local get_aspect
 
 local supposed_aspects = {}
@@ -11,6 +32,9 @@ local supposed_aspects = {}
 function I.load_supposed_aspects(tbl)
 	if tbl then
 		supposed_aspects = tbl
+		for _, v in pairs(tbl) do
+			setmetatable(v, signal_aspect_metatable)
+		end
 	end
 end
 
@@ -41,11 +65,14 @@ end
 
 local function adjust_aspect(pos, asp)
 	asp = table.copy(I.signal_convert_aspect_if_necessary(asp))
+	setmetatable(asp, signal_aspect_metatable)
 
 	local mainpos = D.get_main(pos)
 	local nxtasp
-	if asp.main ~= 0 and mainpos then
+	if mainpos then
 		nxtasp = get_aspect(mainpos)
+	end
+	if asp.main ~= 0 and mainpos then
 		asp.dst = nxtasp.main
 	else
 		asp.dst = nil
@@ -59,7 +86,10 @@ local function adjust_aspect(pos, asp)
 	if stype == 2 then
 		local group = suppasp.group
 		local name
-		if asp.main ~= 0 and nxtasp and nxtasp.type2group == group and nxtasp.type2name then
+		if suppasp.dst_shift and nxtasp then
+			asp.main = nil
+			name = A.type1_to_type2main(nxtasp, group, suppasp.dst_shift)
+		elseif asp.main ~= 0 and nxtasp and nxtasp.type2group == group and nxtasp.type2name then
 			name = A.get_type2_dst(group, nxtasp.type2name)
 		else
 			name = A.type1_to_type2main(asp, group)
@@ -79,7 +109,7 @@ local function get_real_aspect(pos)
 		local asp = ndef.advtrains.get_aspect(pos, node) or I.DANGER
 		local suppasp = get_supported_aspects(pos)
 		if suppasp.type == 2 then
-			asp = A.type2main_to_type1(suppasp.group, asp)
+			asp = A.type2_to_type1(suppasp, asp)
 		end
 		return adjust_aspect(pos, asp)
 	end
@@ -108,11 +138,6 @@ local function set_aspect(pos, asp, skipdst)
 		if (not skipdst) and aspect_changed then
 			D.update_main(pos)
 		end
-		--[[
-		local dbgmsg = string.format("[%s]set_aspect(%s,%s,%s)", os.clock(), minetest.pos_to_string(pos), minetest.serialize(asp), tostring(skipdst))
-		dbgmsg = debug.traceback(dbgmsg, 2)
-		minetest.chat_send_all(dbgmsg)
-		--]]
 	end
 end
 
diff --git a/advtrains_interlocking/signal_aspect_ui.lua b/advtrains_interlocking/signal_aspect_ui.lua
index 30b5165..ccedb01 100644
--- a/advtrains_interlocking/signal_aspect_ui.lua
+++ b/advtrains_interlocking/signal_aspect_ui.lua
@@ -219,7 +219,7 @@ local function get_aspect_from_formspec_t1(suppasp, fields)
 end
 
 local function get_aspect_from_formspec_t2(suppasp, fields)
-	local asp = advtrains.interlocking.aspects.type2main_to_type1(suppasp.group, tonumber(fields.asp))
+	local asp = advtrains.interlocking.aspects.type2_to_type1(suppasp, tonumber(fields.asp))
 	return asp
 end
 
diff --git a/advtrains_interlocking/signal_aspects.lua b/advtrains_interlocking/signal_aspects.lua
index 5c4948b..c381fd2 100644
--- a/advtrains_interlocking/signal_aspects.lua
+++ b/advtrains_interlocking/signal_aspects.lua
@@ -67,7 +67,9 @@ local function get_type2_dst(group, name)
 	return def.main[math.max(1, aspidx-1)].name
 end
 
-local function type2main_to_type1(name, asp)
+local function type2_to_type1(suppasp, asp)
+	local name = suppasp.group
+	local shift = suppasp.dst_shift
 	local def = type2defs[name]
 	if not def then
 		return nil
@@ -78,18 +80,26 @@ local function type2main_to_type1(name, asp)
 	else
 		aspidx = def.main[asp] or 2
 	end
-	local asptbl = def.main[aspidx]
+	local realidx = math.min(#def.main, aspidx+(shift or 0))
+	local asptbl = def.main[realidx]
 	if not asptbl then
 		return nil
 	end
 	if type(asp) == "number" then
 		asp = asptbl.name
 	end
-	local dst = def.main[math.min(#def.main, aspidx+1)].main
+	local main, shunt, dst
+	if shift then
+		dst = asptbl.main
+	else
+		main = asptbl.main
+		shunt = asptbl.shunt
+		dst = def.main[math.min(#def.main, aspidx+1)].main
+	end
 
 	local t = {
-		main = asptbl.main,
-		shunt = asptbl.shunt,
+		main = main,
+		shunt = shunt,
 		proceed_as_main = asptbl.proceed_as_main,
 		type2name = asp,
 		type2group = name,
@@ -101,31 +111,28 @@ local function type2main_to_type1(name, asp)
 	return t
 end
 
-local function type1_to_type2main(asp, group)
+local function type1_to_type2main(asp, group, shift)
 	local def = type2defs[group]
 	if not def then
 		return nil
 	end
-	if group == asp.type2group and def.main[asp.type2name] then
-		return asp.type2name
-	end
 	local t_main = def.main
 	local idx
-	if not asp.main or asp.main == -1 then
+	if group == asp.type2group and t_main[asp.type2name] then
+		idx = t_main[asp.type2name]
+	elseif not asp.main or asp.main == -1 then
 		idx = 1
 	elseif asp.main == 0 then
 		idx = #t_main
 	else
-		idx = math.max(#t_main-1, 1)
+		idx = #t_main-1
 	end
-	return t_main[idx].name
+	return t_main[math.max(1, idx-(shift or 0))].name
 end
 
 local function equalp(asp1, asp2)
 	if asp1 == asp2 then -- same reference
 		return true
-	elseif asp1.type2group and asp1.type2group == asp2.type2group then -- type2 with the same group
-		return asp1.type2name == asp2.type2name
 	else
 		for _, k in pairs {"main", "shunt", "dst"} do
 			if asp1[k] ~= asp2[k] then
@@ -133,6 +140,9 @@ local function equalp(asp1, asp2)
 			end
 		end
 	end
+	if asp1.type2group and asp1.type2group == asp2.type2group then
+		return asp1.type2name == asp2.type2name
+	end
 	return true
 end
 
@@ -144,7 +154,7 @@ return {
 	register_type2 = register_type2,
 	get_type2_definition = get_type2_definition,
 	get_type2_dst = get_type2_dst,
-	type2main_to_type1 = type2main_to_type1,
+	type2_to_type1 = type2_to_type1,
 	type1_to_type2main = type1_to_type2main,
 	equalp = equalp,
 	not_equalp = not_equalp,
diff --git a/advtrains_interlocking/spec/basic_signalling_spec.lua b/advtrains_interlocking/spec/basic_signalling_spec.lua
index 0b79972..720b274 100644
--- a/advtrains_interlocking/spec/basic_signalling_spec.lua
+++ b/advtrains_interlocking/spec/basic_signalling_spec.lua
@@ -44,7 +44,7 @@ world.layout {
 
 describe("API for supposed signal aspects", function()
 	it("should load and save data properly", function()
-		local tbl = {_foo = true}
+		local tbl = {_foo = {}}
 		I.load_supposed_aspects(tbl)
 		assert.same(tbl, I.save_supposed_aspects())
 	end)
diff --git a/advtrains_interlocking/tcb_ts_ui.lua b/advtrains_interlocking/tcb_ts_ui.lua
index 9f88296..3898d73 100755
--- a/advtrains_interlocking/tcb_ts_ui.lua
+++ b/advtrains_interlocking/tcb_ts_ui.lua
@@ -198,20 +198,24 @@ minetest.register_on_punchnode(function(pos, node, player, pointed_thing)
 			if is_signal then
 				local ndef = minetest.registered_nodes[node.name]
 				if ndef and ndef.advtrains and ndef.advtrains.set_aspect then
-					local tcbs = ildb.get_tcbs(sigd)
-					if tcbs then
-						tcbs.signal = pos
-						if not tcbs.signal_name then
-							tcbs.signal_name = "Signal at "..minetest.pos_to_string(sigd.p)
+					if ndef.advtrains.supported_aspects and not ndef.advtrains.supported_aspects.dst_shift then
+						local tcbs = ildb.get_tcbs(sigd)
+						if tcbs then
+							tcbs.signal = pos
+							if not tcbs.signal_name then
+								tcbs.signal_name = "Signal at "..minetest.pos_to_string(sigd.p)
+							end
+							if not tcbs.routes then
+								tcbs.routes = {}
+							end
+							ildb.set_sigd_for_signal(pos, sigd)
+							minetest.chat_send_player(pname, "Configuring TCB: Successfully assigned signal.")
+							advtrains.interlocking.show_ip_form(pos, pname, true)
+						else
+							minetest.chat_send_player(pname, "Configuring TCB: Internal error, TCBS doesn't exist. Aborted.")
 						end
-						if not tcbs.routes then
-							tcbs.routes = {}
-						end
-						ildb.set_sigd_for_signal(pos, sigd)
-						minetest.chat_send_player(pname, "Configuring TCB: Successfully assigned signal.")
-						advtrains.interlocking.show_ip_form(pos, pname, true)
 					else
-						minetest.chat_send_player(pname, "Configuring TCB: Internal error, TCBS doesn't exist. Aborted.")
+						minetest.chat_send_player(pname, "Configuring TCB: Cannot use distant signal. Aborted.")
 					end
 				else
 					minetest.chat_send_player(pname, "Configuring TCB: Cannot use static signals for routesetting. Aborted.")
diff --git a/advtrains_signals_japan/init.lua b/advtrains_signals_japan/init.lua
index 2062a21..59640b1 100644
--- a/advtrains_signals_japan/init.lua
+++ b/advtrains_signals_japan/init.lua
@@ -401,6 +401,7 @@ for _, rtab in ipairs {
 					supported_aspects = {
 						type = 2,
 						group = siginfo.typename,
+						dst_shift = siginfo.isdst and 0,
 					},
 					get_aspect = function()
 						return asp
-- 
cgit v1.2.3


From ba98fa53780bf19266d7e5049fd7ec31eaad18bf Mon Sep 17 00:00:00 2001
From: "Y. Wang" <yw05@forksworld.de>
Date: Fri, 4 Nov 2022 11:15:04 +0100
Subject: Harden type 2 signal group API; add test for type 2 main signals

---
 advtrains_interlocking/signal_aspects.lua  |  17 +++--
 advtrains_interlocking/spec/type2_spec.lua | 103 +++++++++++++++++++++++++++++
 2 files changed, 115 insertions(+), 5 deletions(-)
 create mode 100644 advtrains_interlocking/spec/type2_spec.lua

(limited to 'advtrains_interlocking/spec')

diff --git a/advtrains_interlocking/signal_aspects.lua b/advtrains_interlocking/signal_aspects.lua
index 37af7aa..65e970f 100644
--- a/advtrains_interlocking/signal_aspects.lua
+++ b/advtrains_interlocking/signal_aspects.lua
@@ -9,13 +9,15 @@ local type2defs = {}
 local function register_type2(def)
 	local t = {type = 2}
 	local name = def.name
-	if type2defs[name] then
-		return error("Name " .. name .. " already used")
-	elseif type(name) ~= "string" then
+	if type(name) ~= "string" then
 		return error("Name is not a string")
+	elseif type2defs[name] then
+		return error(string.format("Attempt to redefine type 2 signal aspect group %q, previously defined in %s", name, type2defs[name].defined))
 	end
 	t.name = name
 
+	t.defined = debug.getinfo(2, "S").short_src or "[?]"
+
 	local label = def.label or name
 	if type(label) ~= "string" then
 		return error("Label is not a string")
@@ -54,7 +56,12 @@ end
 -- @return[1] The definition for the signal group (if present).
 -- @return[2] The nil constant (otherwise).
 local function get_type2_definition(name)
-	return type2defs[name]
+	local t = type2defs[name]
+	if t then
+		return table.copy(t)
+	else
+		return nil
+	end
 end
 
 --- Get the name of the distant aspect before the current aspect.
@@ -151,7 +158,7 @@ local function type1_to_type2main(asp, group, shift)
 	return t_main[math.max(1, idx-(shift or 0))].name
 end
 
---- Compare two signal aspect tables.
+--- Compare two type 1 signal aspect tables.
 -- @function equalp
 -- @param asp1 The first signal aspect table.
 -- @param asp2 The second signal aspect table.
diff --git a/advtrains_interlocking/spec/type2_spec.lua b/advtrains_interlocking/spec/type2_spec.lua
new file mode 100644
index 0000000..514f6aa
--- /dev/null
+++ b/advtrains_interlocking/spec/type2_spec.lua
@@ -0,0 +1,103 @@
+require "mineunit"
+mineunit("core")
+
+_G.advtrains = {
+	interlocking = {
+		aspects = sourcefile("signal_aspects"),
+	},
+	ndb = {
+		get_node = minetest.get_node,
+		swap_node = minetest.swap_node,
+	}
+}
+
+fixture("advtrains_helpers")
+sourcefile("database")
+sourcefile("signal_api")
+sourcefile("distant")
+sourcefile("signal_aspect_accessors")
+
+local A = advtrains.interlocking.aspects
+local D = advtrains.distant
+local I = advtrains.interlocking
+local N = advtrains.ndb
+
+local type2def = {
+	name = "foo",
+	main = {
+		{name = "proceed", main = -1},
+		{name = "caution"},
+		{name = "danger", main = 0},
+	},
+}
+
+local asps = {}
+for _, v in pairs(type2def.main) do
+	minetest.register_node("advtrains_interlocking:" .. v.name, {
+		advtrains = {
+			supported_aspects = {
+				type = 2,
+				group = "foo",
+			},
+			get_aspect = function() return v.name end,
+			set_aspect = function(pos, _, name)
+				N.swap_node(pos, {name = "advtrains_interlocking:" .. name})
+			end,
+		}
+	})
+	asps[v.name] = {
+		main = v.main,
+		type2group = "foo",
+		type2name = v.name,
+	}
+end
+
+local origin = vector.new(0, 0, 0)
+local dstpos = vector.new(0, 0, 1)
+
+world.layout {
+	{origin, "advtrains_interlocking:danger"},
+	{dstpos, "advtrains_interlocking:proceed"},
+}
+
+describe("type 2 signal group registration", function()
+	it("should work", function()
+		A.register_type2(type2def)
+		assert(A.get_type2_definition("foo"))
+	end)
+	it("should only be allowed once for the same group", function()
+		assert.has.errors(function() A.register_type2(type2def) end)
+	end)
+	it("should handle nonexistant groups", function()
+		assert.is_nil(A.get_type2_definition("something_else"))
+	end)
+end)
+
+describe("signal aspect conversion", function()
+	it("should work for converting from type 1 to type 2", function()
+		assert.equal("danger", A.type1_to_type2main({main = 0}, "foo"))
+		assert.equal("caution", A.type1_to_type2main({main = 6}, "foo"))
+		assert.equal("proceed", A.type1_to_type2main({}, "foo"))
+	end)
+	-- Type 2 -> type 1 conversion is tested with signal aspect accessors
+end)
+
+describe("type 2 signals", function()
+	it("should support distant signaling", function()
+		assert.equal("caution", A.get_type2_dst("foo", 3))
+		assert.equal("proceed", A.get_type2_dst("foo", "caution"))
+		assert.equal("proceed", A.get_type2_dst("foo", "proceed"))
+	end)
+	it("should work with accessors", function()
+		assert.same(asps.danger, I.signal_get_aspect(origin))
+		local newasp = {type2group = "foo", type2name = "proceed", main = 6}
+		I.signal_set_aspect(origin, newasp)
+		assert.same(newasp, I.signal_get_aspect(origin))
+	end)
+	it("should work with distant signaling", function()
+		assert.same(asps.proceed, I.signal_get_aspect(dstpos))
+		local dstasp = {type2group = "foo", type2name = "proceed", dst = 6, main = -1}
+		D.assign(origin, dstpos)
+		assert.same(dstasp, I.signal_get_aspect(dstpos))
+	end)
+end)
-- 
cgit v1.2.3


From d290e8e994fc741c97f4c1beddf7ec31da923e3d Mon Sep 17 00:00:00 2001
From: "Y. Wang" <yw05@forksworld.de>
Date: Fri, 4 Nov 2022 12:41:21 +0100
Subject: Increase testing coverage for signal_aspects API

---
 advtrains_interlocking/signal_aspects.lua  |  5 ++++-
 advtrains_interlocking/spec/type2_spec.lua | 32 +++++++++++++++++++++---------
 2 files changed, 27 insertions(+), 10 deletions(-)

(limited to 'advtrains_interlocking/spec')

diff --git a/advtrains_interlocking/signal_aspects.lua b/advtrains_interlocking/signal_aspects.lua
index 65e970f..14e04c7 100644
--- a/advtrains_interlocking/signal_aspects.lua
+++ b/advtrains_interlocking/signal_aspects.lua
@@ -117,12 +117,15 @@ local function type2_to_type1(suppasp, asp)
 		shunt = asptbl.shunt
 		dst = def.main[math.min(#def.main, aspidx+1)].main
 	end
+	if main == 0 then
+		dst = nil
+	end
 
 	local t = {
 		main = main,
 		shunt = shunt,
 		proceed_as_main = asptbl.proceed_as_main,
-		type2name = asp,
+		type2name = asptbl.name,
 		type2group = name,
 		dst = dst,
 	}
diff --git a/advtrains_interlocking/spec/type2_spec.lua b/advtrains_interlocking/spec/type2_spec.lua
index 514f6aa..ac23574 100644
--- a/advtrains_interlocking/spec/type2_spec.lua
+++ b/advtrains_interlocking/spec/type2_spec.lua
@@ -31,7 +31,6 @@ local type2def = {
 	},
 }
 
-local asps = {}
 for _, v in pairs(type2def.main) do
 	minetest.register_node("advtrains_interlocking:" .. v.name, {
 		advtrains = {
@@ -45,11 +44,10 @@ for _, v in pairs(type2def.main) do
 			end,
 		}
 	})
-	asps[v.name] = {
-		main = v.main,
-		type2group = "foo",
-		type2name = v.name,
-	}
+end
+
+local function asp(group, name, dst)
+	return A.type2_to_type1({group = group, dst_shift = shift}, name)
 end
 
 local origin = vector.new(0, 0, 0)
@@ -71,6 +69,12 @@ describe("type 2 signal group registration", function()
 	it("should handle nonexistant groups", function()
 		assert.is_nil(A.get_type2_definition("something_else"))
 	end)
+	it("should reject invalid definitions", function()
+		assert.has.errors(function() A.register_type2({}) end)
+		assert.has.errors(function() A.register_type2({name="",label={}}) end)
+		assert.has.errors(function() A.register_type2({name="",main={{name={}}}}) end)
+		assert.has.errors(function() A.register_type2({name="",main={{name="",label={}}}}) end)
+	end)
 end)
 
 describe("signal aspect conversion", function()
@@ -79,7 +83,17 @@ describe("signal aspect conversion", function()
 		assert.equal("caution", A.type1_to_type2main({main = 6}, "foo"))
 		assert.equal("proceed", A.type1_to_type2main({}, "foo"))
 	end)
-	-- Type 2 -> type 1 conversion is tested with signal aspect accessors
+	it("should reject invalid type 2 signal information", function()
+		assert.is_nil(A.type1_to_type2main({}, "?"))
+		assert.is_nil(A.type2_to_type1({}, "x"))
+		assert.same(asp("foo","caution"), asp("foo", "x"))
+	end)
+	it("should accept integer indices for type 2 signal aspects", function()
+		assert.same(asp("foo", "caution"), asp("foo", 2))
+		assert.same(asp("foo", "danger"), asp("foo", 10))
+		assert.same(asp("foo", "proceed"), asp("foo", 1))
+		assert.is_nil(asp("foo", -0.5))
+	end)
 end)
 
 describe("type 2 signals", function()
@@ -89,13 +103,13 @@ describe("type 2 signals", function()
 		assert.equal("proceed", A.get_type2_dst("foo", "proceed"))
 	end)
 	it("should work with accessors", function()
-		assert.same(asps.danger, I.signal_get_aspect(origin))
+		assert.same(asp("foo","danger"), I.signal_get_aspect(origin))
 		local newasp = {type2group = "foo", type2name = "proceed", main = 6}
 		I.signal_set_aspect(origin, newasp)
 		assert.same(newasp, I.signal_get_aspect(origin))
 	end)
 	it("should work with distant signaling", function()
-		assert.same(asps.proceed, I.signal_get_aspect(dstpos))
+		assert.same(asp("foo","proceed"), I.signal_get_aspect(dstpos))
 		local dstasp = {type2group = "foo", type2name = "proceed", dst = 6, main = -1}
 		D.assign(origin, dstpos)
 		assert.same(dstasp, I.signal_get_aspect(dstpos))
-- 
cgit v1.2.3


From d443d8e07af89665a6bb3d87af91f43f08a6c47e Mon Sep 17 00:00:00 2001
From: "Y. Wang" <yw05@forksworld.de>
Date: Fri, 6 Jan 2023 18:23:15 +0100
Subject: Distant signaling: avoid signal signs

---
 advtrains_interlocking/distant.lua                  | 21 +++++++++++++++++++++
 advtrains_interlocking/distant_ui.lua               | 10 +++++++++-
 advtrains_interlocking/signal_api.lua               | 10 +++++++---
 advtrains_interlocking/signal_aspect_accessors.lua  |  2 +-
 .../spec/basic_signalling_spec.lua                  | 17 ++++++++++++++++-
 5 files changed, 54 insertions(+), 6 deletions(-)

(limited to 'advtrains_interlocking/spec')

diff --git a/advtrains_interlocking/distant.lua b/advtrains_interlocking/distant.lua
index 726c2b3..4175875 100644
--- a/advtrains_interlocking/distant.lua
+++ b/advtrains_interlocking/distant.lua
@@ -85,6 +85,23 @@ local function unassign_all(pos, force)
 	unassign_dst(pos, force)
 end
 
+--- Check whether a signal is "appropriate" for the distant signal system.
+-- Currently, a signal is considered appropriate if its signal aspect can be set.
+-- @function appropriate_signal
+-- @param pos The position of the signal
+local function appropriate_signal(pos)
+	local node = advtrains.ndb.get_node(pos)
+	local ndef = minetest.registered_nodes[node.name] or {}
+	if not ndef then
+		return false
+	end
+	local atdef = ndef.advtrains
+	if not atdef then
+		return false
+	end
+	return atdef.supported_aspects and atdef.set_aspect and true
+end
+
 --- Assign a distant signal to a main signal.
 -- @function assign
 -- @param main The position of the main signal.
@@ -92,6 +109,9 @@ end
 -- @param[opt="manual"] by The method of assignment.
 -- @param[opt=false] skip_update Whether to skip callbacks.
 local function assign(main, dst, by, skip_update)
+	if not (appropriate_signal(main) and appropriate_signal(dst)) then
+		return
+	end
 	local pts_main = pts(main)
 	local pts_dst = pts(dst)
 	local t = db_distant[pts_main]
@@ -177,4 +197,5 @@ advtrains.distant = {
 	update_main = update_main,
 	update_dst = update_dst,
 	update_signal = update_signal,
+	appropriate_signal = appropriate_signal,
 }
diff --git a/advtrains_interlocking/distant_ui.lua b/advtrains_interlocking/distant_ui.lua
index 0907684..bb66dc4 100644
--- a/advtrains_interlocking/distant_ui.lua
+++ b/advtrains_interlocking/distant_ui.lua
@@ -56,6 +56,10 @@ local function init_signal_assignment(pname, pos)
 		minetest.chat_send_player(pname, attrans("This operation is not allowed without the @1 privilege.", "interlocking"))
 		return
 	end
+	if not D.appropriate_signal(pos) then
+		minetest.chat_send_player(pname, attrans("Incompatible signal."))
+		return
+	end
 	signal_pos[pname] = pos
 	minetest.chat_send_player(pname, attrans("Please punch the signal to use as the main signal."))
 end
@@ -66,6 +70,10 @@ local function init_distant_assignment(pname, pos)
 		minetest.send_chat_player(pname, attrans("This operation is now allowed without the @1 privilege.", "interlocking"))
 		return
 	end
+	if not D.appropriate_signal(pos) then
+		minetest.chat_send_player(pname, attrans("Incompatible signal."))
+		return
+	end
 	distant_pos[pname] = pos
 	minetest.chat_send_player(pname, attrans("Please punch the signal to use as the distant signal."))
 end
@@ -87,7 +95,7 @@ minetest.register_on_punchnode(function(pos, node, player, pointed_thing)
 	signal_pos[pname] = nil
 	distant_pos[pname] = nil
 	local is_signal = minetest.get_item_group(node.name, "advtrains_signal") >= 2
-	if not is_signal then
+	if not (is_signal and D.appropriate_signal(pos)) then
 		minetest.chat_send_player(pname, attrans("Incompatible signal."))
 		return
 	end
diff --git a/advtrains_interlocking/signal_api.lua b/advtrains_interlocking/signal_api.lua
index cd408d7..1b4a21c 100644
--- a/advtrains_interlocking/signal_api.lua
+++ b/advtrains_interlocking/signal_api.lua
@@ -159,16 +159,20 @@ function advtrains.interlocking.show_ip_form(pos, pname, only_notset)
 		return
 	end
 	local ipform, pts, connid = advtrains.interlocking.make_ip_formspec_component(pos, 0.5, 0.5, 7)
-	local form = table.concat {
+	local form = {
 		"formspec_version[4]",
-		"size[8,6.75]",
+		"size[8,2.25]",
 		ipform,
-		advtrains.interlocking.make_dst_formspec_component(pos, 0.5, 2, 7, 4.25),
 	}
 	if pts then
 		local ipos = minetest.string_to_pos(pts)
 		ipmarker(ipos, connid)
 	end
+	if advtrains.distant.appropriate_signal(pos) then
+		form[#form+1] = advtrains.interlocking.make_dst_formspec_component(pos, 0.5, 2, 7, 4.25)
+		form[2] = "size[8,6.75]"
+	end
+	form = table.concat(form)
 	if not only_notset or not pts then
 		minetest.show_formspec(pname, "at_il_propassign_"..minetest.pos_to_string(pos), form)
 	end
diff --git a/advtrains_interlocking/signal_aspect_accessors.lua b/advtrains_interlocking/signal_aspect_accessors.lua
index e55814e..e419515 100644
--- a/advtrains_interlocking/signal_aspect_accessors.lua
+++ b/advtrains_interlocking/signal_aspect_accessors.lua
@@ -144,7 +144,7 @@ local function get_real_aspect(pos)
 	if ndef.advtrains and ndef.advtrains.get_aspect then
 		local asp = ndef.advtrains.get_aspect(pos, node) or I.DANGER
 		local suppasp = get_supported_aspects(pos)
-		if suppasp.type == 2 then
+		if suppasp and suppasp.type == 2 then
 			asp = A.type2_to_type1(suppasp, asp)
 		end
 		return adjust_aspect(pos, asp)
diff --git a/advtrains_interlocking/spec/basic_signalling_spec.lua b/advtrains_interlocking/spec/basic_signalling_spec.lua
index 720b274..cce0f15 100644
--- a/advtrains_interlocking/spec/basic_signalling_spec.lua
+++ b/advtrains_interlocking/spec/basic_signalling_spec.lua
@@ -23,6 +23,12 @@ sourcefile("signal_api")
 sourcefile("signal_aspect_accessors")
 fixture("../../demosignals")
 
+minetest.register_node("advtrains_interlocking:signal_sign", {
+	advtrains = {
+		get_aspcet = function() return {main = 19} end
+	}
+})
+
 local D = advtrains.distant
 local I = advtrains.interlocking
 
@@ -32,7 +38,7 @@ local stub_aspect_t1 = {
 	danger = {main = 0, shunt = false},
 }
 local stub_pos_t1 = {}
-for i = 1, 3 do
+for i = 1, 4 do
 	stub_pos_t1[i] = {x = 1, y = 0, z = i}
 end
 
@@ -40,6 +46,7 @@ world.layout {
 	{stub_pos_t1[1], "advtrains_interlocking:ds_danger"},
 	{stub_pos_t1[2], "advtrains_interlocking:ds_slow"},
 	{stub_pos_t1[3], "advtrains_interlocking:ds_free"},
+	{stub_pos_t1[4], "advtrains_interlocking:signal_sign"},
 }
 
 describe("API for supposed signal aspects", function()
@@ -84,4 +91,12 @@ describe("Distant signaling", function()
 		assert.same({}, {D.get_main(stub_pos_t1[3])})
 		assert.same(stub_aspect_t1.free, I.signal_get_aspect(stub_pos_t1[3]))
 	end)
+	it("should reject signal signs", function()
+		D.assign(stub_pos_t1[1], stub_pos_t1[4])
+		assert.same({}, D.get_dst(stub_pos_t1[1]))
+		assert.same({}, {D.get_main(stub_pos_t1[4])})
+		D.assign(stub_pos_t1[4], stub_pos_t1[1])
+		assert.same({}, D.get_dst(stub_pos_t1[4]))
+		assert.same({}, {D.get_main(stub_pos_t1[1])})
+	end)
 end)
-- 
cgit v1.2.3


From e25b1c744dad7daa561ee0b23b006bc616f88f23 Mon Sep 17 00:00:00 2001
From: "Y. Wang" <yw05@forksworld.de>
Date: Sun, 26 Mar 2023 11:53:00 +0200
Subject: Cancel type 2 signals; introduce signal groups for all signals

---
 advtrains_interlocking/README.md                   |  41 ++-
 advtrains_interlocking/aspect.lua                  | 290 +++++++++++++++++++++
 advtrains_interlocking/distant.lua                 |   1 -
 advtrains_interlocking/init.lua                    |   2 +-
 advtrains_interlocking/signal_api.lua              |  28 +-
 advtrains_interlocking/signal_aspect_accessors.lua |  80 ++----
 advtrains_interlocking/signal_aspect_ui.lua        | 127 ++-------
 advtrains_interlocking/signal_aspects.lua          | 202 --------------
 .../spec/basic_signalling_spec.lua                 |  26 +-
 advtrains_interlocking/spec/signal_group_spec.lua  |  95 +++++++
 advtrains_interlocking/spec/type2_spec.lua         | 117 ---------
 advtrains_signals_japan/init.lua                   |  18 +-
 12 files changed, 474 insertions(+), 553 deletions(-)
 create mode 100644 advtrains_interlocking/aspect.lua
 delete mode 100644 advtrains_interlocking/signal_aspects.lua
 create mode 100644 advtrains_interlocking/spec/signal_group_spec.lua
 delete mode 100644 advtrains_interlocking/spec/type2_spec.lua

(limited to 'advtrains_interlocking/spec')

diff --git a/advtrains_interlocking/README.md b/advtrains_interlocking/README.md
index 636ad67..d4a2699 100644
--- a/advtrains_interlocking/README.md
+++ b/advtrains_interlocking/README.md
@@ -2,12 +2,6 @@
 
 The `advtrains_interlocking` mod provides various interlocking and signaling features for Advtrains.
 
-## Signal types
-There are two types of signals in Advtrains:
-
-* Type 1 (speed signals): These signals only give speed information.
-* Type 2 (route signals): These signals mainly provide route information, but sometimes also provide speed information.
-
 ## Signal aspect tables
 
 Signal aspects are represented using tables with the following (optional) fields:
@@ -16,15 +10,16 @@ Signal aspects are represented using tables with the following (optional) fields
 * `dst`: The distant signal aspect. It provides information on the permitted speed after passing the next signal.
 * `shunt`: Whether the train may proceed in shunt mode and, if the main aspect is danger, proceed in shunt mode.
 * `proceed_as_main`: Whether the train should exit shunt mode when proceeding.
-* `type2group`: The type 2 group of the signal.
-* `type2name`: The type 2 signal aspect name.
+* `group`: The name of the signal group.
+* `name`: The name of the signal aspect.
 
 The `main` and `dst` fields may be:
 
 * An positive number indicating the permitted speed,
 * The number 0, indicating that the train should expect to stop at the current signal (or, for the `dst` field, the next signal),
-* The number -1, indicating that the train can proceed (or, for the `dst` field, expect to proceed) at maximum speed, or
-* The constant `false` or `nil`, indicating no change to the speed restriction.
+* The number -1, indicating that the train can proceed (or, for the `dst` field, expect to proceed) at maximum speed,
+* The constant `false`, indicating no change to the speed restriction, or
+* The constant `nil`, indicating that the default value for the name aspect (if present) is used. If no valid signal aspect is named, or the signal aspect does not provide a default value, the value is assumed to be `false`.
 
 ### Node definitions
 
@@ -38,22 +33,19 @@ The node definition should contain an `advtrains` field.
 
 The `advtrains` field of the node definition should contain a `supported_aspects` table for signals with variable aspects.
 
-For type 1 signals, the `supported_aspects` table should contain the following fields:
+The `supported_aspects` table should contain the following fields:
 
 * `main`: A list of values supported for the main aspect.
 * `dst`: A list of values supported for the distant aspect.
 * `shunt`: The value for the `shunt` field of the signal aspect or `nil` if the value is variable.
 * `proceed_as_main`: The value for the `proceed_as_main` field of the signal aspect.
-
-For type 2 signals, the `supported_aspects` table should contain the following fields:
-
-* `type`: The numeric constant `2`.
-* `group`: The type 2 signal group.
+* `group`: The name of the signal group.
+* `name`: A list of supported (named) aspects.
 * `dst_shift`: The phase shift for distant/repeater signals. This field should not be set for main signals.
 
 The `advtrains` field of the node definition should contain a `get_aspect` function. This function is given the position of the signal and the node at the position. It should return the signal aspect table or, in the case of type 2 signals, the name of the signal aspect.
 
-For signals with variable aspects, a corresponding `set_aspect` function should also be defined. This function is given the position of the signal, the node at the position, and the new aspect (or, in the case of type 2 signals, the name of the new signal aspect). For type 1 signals, the new aspect is not guranteed to be supported by the signal itself.
+For signals with variable aspects, a corresponding `set_aspect` function should also be defined. This function is given the position of the signal, the node at the position, and the new aspect. The new aspect is not guaranteed to be supported by the signal itself.
 
 Signals should also have the following callbacks set:
 
@@ -63,23 +55,20 @@ Signals should also have the following callbacks set:
 
 Alternatively, custom callbacks should call the respective functions.
 
-## Type 2 signal groups
+## Signal groups
 
-Type 2 signals belong to signal gruops, which are registered using `advtrains.interlocking.aspects.register_type2`.
+Signals may belong to signal groups are registered using `advtrains.interlocking.aspect.register_group`.
 
 Signal group definitions include the following fields:
 
 * `name`: The internal name of the signal group. It is recommended to use the mod name as a prefix to avoid name collisions.
 * `label`: The description of the signal group.
-* `main`: A list of signal aspects, from the least restrictive (i.e. proceed) to the most restrictive (i.e. danger).
+* `aspects`: A table of signal aspects. Entries with string indices define the signal aspect with the name. Entries with numeric indices (starting from 1, counting upward) contain a list of corresponding aspect names (the first entry is preferred) and are mainly used for routing, where larger indices indicate that the signal with the aspect is closer to the signal with the "danger" (or similar) aspect.
 
 Each aspect in the signal group definition table should contain the following fields:
 
-* `name`: The internal name of the signal aspect.
 * `label`: The description of the signal aspect.
-* `main`, `shunt`, `proceed_as_main`: The fields corresponding to the ones in signal aspect tables.
-
-Type 2 signal aspects are then referred to with the aspect names within the group.
+* `main`, `shunt`, `proceed_as_main`: The default values for the aspect. Note that the `dst` field has no default value as it is automatically adjusted.
 
 ## Notes
 
@@ -89,8 +78,8 @@ It is allowed to provide other methods of setting the signal aspect. However:
 * Please call `advtrains.interlocking.signal_readjust_aspect` after the signal aspect has changed.
 
 ## Examples
-An example of type 1 signals can be found in `advtrains_signals_ks`, which provides a subset of German signals.
+An example of speed signals can be found in `advtrains_signals_ks`, which provides a subset of German signals.
 
-An example of type 2 signals can be found in `advtrains_signals_japan`, which provides a subset of Japanese signals.
+An example of route signals can be found in `advtrains_signals_japan`, which provides a subset of Japanese signals.
 
 The mods mentioned above are also used for demonstation purposes and can also be used for testing.
diff --git a/advtrains_interlocking/aspect.lua b/advtrains_interlocking/aspect.lua
new file mode 100644
index 0000000..1575fb1
--- /dev/null
+++ b/advtrains_interlocking/aspect.lua
@@ -0,0 +1,290 @@
+--- Signal aspect handling.
+-- @module advtrains.interlocking.aspect
+
+local registered_groups = {}
+
+local named_aspect_aspfields = {main = true, shunt = true, proceed_as_main = true}
+
+local signal_aspect = {}
+
+local signal_aspect_metatable = {
+	__eq = function(asp1, asp2)
+		for _, k in pairs {"main", "dst", "shunt", "proceed_as_main"} do
+			local v1, v2 = (asp1[k] or false), (asp2[k] or false)
+			if v1 ~= v2 then
+				return false
+			end
+		end
+		if asp1.group and asp1.group == asp2.group then
+			return asp1.name == asp2.name
+		end
+		return true
+	end,
+	__index = function(asp, field)
+		local method = signal_aspect[field]
+		if method then
+			return method
+		end
+		if not named_aspect_aspfields[field] then
+			return nil
+		end
+		local group = registered_groups[rawget(asp, "group")]
+		if not group then
+			return false
+		end
+		local aspdef = group.aspects[rawget(asp, "name")]
+		if not aspdef then
+			return false
+		end
+		return aspdef[field] or false
+	end,
+	__tostring = function(asp)
+		local st = {}
+		if asp.group and asp.name then
+			table.insert(st, ("%q in %q"):format(asp.name, asp.group))
+		end
+		if asp.main then
+			table.insert(st, ("current %d"):format(asp.main))
+		end
+		if asp.main ~= 0 then
+			if asp.dst then
+				table.insert(st, string.format("next %d", asp.dst))
+			end
+		end
+		if asp.main ~= 0 and asp.proceed_as_main then
+			table.insert(st, "proceed as main")
+		end
+		return ("[%s]"):format(table.concat(st, ", "))
+	end,
+}
+
+local function quicknew(t)
+	return setmetatable(t, signal_aspect_metatable)
+end
+
+--- Signal aspect class.
+-- @type signal_aspect
+
+--- Return a plain version of the signal aspect.
+-- @param[opt=false] raw Bypass metamethods when fetching signal aspects
+-- @return A plain copy of the signal aspect object.
+function signal_aspect:plain(raw)
+	local t = {}
+	for _, k in pairs {"main", "dst", "shunt", "proceed_as_main", "group", "name"} do
+		local v
+		if raw then
+			v = rawget(self, k)
+		else
+			v = self[k]
+		end
+		t[k] = v
+	end
+	return t
+end
+
+--- Create (or copy) a signal aspect object.
+-- Note that signal aspect objects can also be created by calling the `advtrains.interlocking.aspect` table.
+-- @return The newly created signal aspect object.
+function signal_aspect:new()
+	if type(self) ~= "table" then
+		return quicknew{}
+	end
+	local newasp = {}
+	for _, k in pairs {"main", "dst"} do
+		if type(self[k]) == "table" then
+			if self[k].free then
+				newasp[k] = self[k].speed
+			else
+				newasp[k] = 0
+			end
+		else
+			newasp[k] = self[k]
+		end
+	end
+	if type(self.shunt) == "table" then
+		newasp.shunt = self.shunt.free
+		newasp.proceed_as_main = self.shunt.proceed_as_main
+	else
+		newasp.shunt = self.shunt
+	end
+	for _, k in pairs {"group", "name"} do
+		newasp[k] = self[k]
+	end
+	return quicknew(newasp)
+end
+
+--- Modify the signal aspect in-place to fit in the specific signal group.
+-- @param group The signal group. The `nil` indicates a generic group.
+-- @return The (now modified) signal aspect itself.
+function signal_aspect:to_group(group)
+	local cg = self.group
+	local gdef = registered_groups[group]
+	if type(self.name) ~= "string" then
+		self.name = nil
+	end
+	if not gdef then
+		for k in pairs(named_aspect_aspfields) do
+			rawset(self, k, self[k])
+		end
+		self.group = nil
+		self.name = nil
+		return self
+	elseif cg == group and gdef.aspects[self.name] then
+		return self
+	end
+	local newidx = 1
+	if self.main == 0 then
+		newidx = #gdef.aspects
+	end
+	local cgdef = registered_groups[cg]
+	if cgdef then
+		local idx = (cgdef.aspects[self.name] or {}).index
+		if idx then
+			if idx >= #cgdef.aspects then
+				idx = #gdef.aspects
+			elseif idx >= #gdef.aspects then
+				idx = #gdef.aspects-1
+			end
+			newidx = idx
+		end
+	end
+	self.group = group
+	self.name = group.aspects[newidx][1]
+	return self
+end
+
+--- Modify the signal aspect in-place to indicate a specific distant aspect.
+-- @param dst The distant aspect
+-- @param[opt=1] shift The phase shift of the current signal.
+-- @return The (now modified) signal aspect itself.
+function signal_aspect:adjust_distant(dst, shift)
+	if (shift or -1) < 0 then
+		shift = 1
+	end
+	if not dst then
+		self.dst = nil
+		return self
+	end
+	if self.main ~= 0 then
+		self.dst = dst.main
+	else
+		self.dst = nil
+	end
+	local dgdef = registered_groups[dst.group]
+	if dgdef then
+		if self.group == dst.group and shift == 0 then
+			self.name = dst.name
+		else
+			local idx = (dgdef.aspects[dst.name] or {}).index
+			if idx then
+				idx = math.max(idx-shift, 1)
+				self.group = dst.group
+				self.name = dgdef.aspects[idx][1]
+			end
+		end
+	end
+	return self
+end
+
+--- Signal groups.
+-- @section signal_group
+
+--- Register a signal group.
+-- @function register_group
+-- @param def The definition table.
+local function register_group(def)
+	local t = {}
+	local name = def.name
+	if type(name) ~= "string" then
+		return error("Expected signal group name to be a string, got " .. type(name))
+	elseif registered_groups[name] then
+		return error(string.format("Attempt to redefine signal group %q, previously defined in %s", name, registered_groups[name].defined))
+	end
+	t.name = name
+
+	t.defined = debug.getinfo(2, "S").short_src or "[?]"
+
+	local label = def.label or name
+	if type(label) ~= "string" then
+		return error("Label is not a string")
+	end
+	t.label = label
+
+	local mainasps = {}
+	for idx, asp in pairs(def.aspects) do
+		local idxtp = type(idx)
+		if idxtp == "string" then
+			local t = {}
+			t.name = idx
+
+			local label = asp.label or idx
+			if type(label) ~= "string" then
+				return error("Aspect label is not a string")
+			end
+			t.label = label
+
+			for k in pairs(named_aspect_aspfields) do
+				t[k] = asp[k]
+			end
+
+			mainasps[idx] = t
+		end
+	end
+	if #def.aspects < 2 then
+		return error("Insufficient entries in signal aspect list")
+	end
+	for idx, asplist in ipairs(def.aspects) do
+		if type(asplist) ~= "table" then
+			asplist = {asplist}
+		else
+			asplist = table.copy(asplist)
+		end
+		if #asplist < 1 then
+			error("Invalid entry in signal aspect list")
+		end
+		for _, k in ipairs(asplist) do
+			if type(k) ~= "string" then
+				return error("Invalid signal aspect ID")
+			end
+			local asp = mainasps[k]
+			if not asp then
+				return error("Invalid signal aspect ID")
+			end
+			if asp.index ~= nil then
+				return error("Attempt to assign a signal aspect to multiple numeric indices")
+			end
+			asp.index = idx
+		end
+		mainasps[idx] = asplist
+	end
+	t.aspects = mainasps
+
+	registered_groups[name] = t
+end
+
+--- Get the definition of a signal group.
+-- @function get_group_definition
+-- @param name The name of the signal group.
+-- @return[1] The definition for the signal group (if present).
+-- @return[2] The nil constant (otherwise).
+local function get_group_definition(name)
+	local t = registered_groups[name]
+	if t then
+		return table.copy(t)
+	else
+		return nil
+	end
+end
+
+local lib = {
+	register_group = register_group,
+	get_group_definition = get_group_definition,
+}
+
+local libmt = {
+	__call = function(_, ...)
+		return signal_aspect.new(...)
+	end,
+}
+
+return setmetatable(lib, libmt)
diff --git a/advtrains_interlocking/distant.lua b/advtrains_interlocking/distant.lua
index 4175875..32ada82 100644
--- a/advtrains_interlocking/distant.lua
+++ b/advtrains_interlocking/distant.lua
@@ -6,7 +6,6 @@
 local db_distant = {}
 local db_distant_of = {}
 
-local A = advtrains.interlocking.aspects
 local pts = advtrains.encode_pos
 local stp = advtrains.decode_pos
 
diff --git a/advtrains_interlocking/init.lua b/advtrains_interlocking/init.lua
index 1a8ef07..4d959cc 100644
--- a/advtrains_interlocking/init.lua
+++ b/advtrains_interlocking/init.lua
@@ -12,7 +12,7 @@ end
 
 local modpath = minetest.get_modpath(minetest.get_current_modname()) .. DIR_DELIM
 
-advtrains.interlocking.aspects = dofile(modpath.."signal_aspects.lua")
+advtrains.interlocking.aspect = dofile(modpath.."aspect.lua")
 
 dofile(modpath.."database.lua")
 dofile(modpath.."distant.lua")
diff --git a/advtrains_interlocking/signal_api.lua b/advtrains_interlocking/signal_api.lua
index 1b4a21c..ce8854a 100644
--- a/advtrains_interlocking/signal_api.lua
+++ b/advtrains_interlocking/signal_api.lua
@@ -19,27 +19,7 @@ advtrains.interlocking.FULL_FREE = {
 	proceed_as_main = true,
 }
 
-local function convert_aspect_if_necessary(asp)
-	if type(asp.main) == "table" then
-		local newasp = {} 
-		if asp.main.free then
-			newasp.main = asp.main.speed
-		else
-			newasp.main = 0
-		end
-		if asp.dst and asp.dst.free then
-			newasp.dst = asp.dst.speed
-		else
-			newasp.dst = 0
-		end
-		newasp.proceed_as_main = asp.shunt.proceed_as_main
-		newasp.shunt = asp.shunt.free
-		-- Note: info table not transferred, it's not used right now
-		return newasp
-	end
-	return asp
-end
-advtrains.interlocking.signal_convert_aspect_if_necessary = convert_aspect_if_necessary
+advtrains.interlocking.signal_convert_aspect_if_necessary = advtrains.interlocking.aspect
 
 function advtrains.interlocking.update_signal_aspect(tcbs, skipdst)
 	if tcbs.signal then
@@ -79,7 +59,7 @@ function advtrains.interlocking.signal_rc_handler(pos, node, player, itemstack,
 	end
 	advtrains.interlocking.show_signal_form(pos, node, pname)
 end
-	
+
 function advtrains.interlocking.show_signal_form(pos, node, pname)
 	local sigd = advtrains.interlocking.db.get_sigd_for_signal(pos)
 	if sigd then
@@ -92,7 +72,7 @@ function advtrains.interlocking.show_signal_form(pos, node, pname)
 				advtrains.interlocking.signal_set_aspect(pos, aspect)
 			end
 			local isasp = advtrains.interlocking.signal_get_aspect(pos, node)
-			
+
 			advtrains.interlocking.show_signal_aspect_selector(
 				pname,
 				ndef.advtrains.supported_aspects,
@@ -123,7 +103,7 @@ local function ipmarker(ipos, connid)
 	local node_ok, conns, rhe = advtrains.get_rail_info_at(ipos, advtrains.all_tracktypes)
 	if not node_ok then return end
 	local yaw = advtrains.dir_to_angle(conns[connid].c)
-	
+
 	-- using tcbmarker here
 	local obj = minetest.add_entity(vector.add(ipos, {x=0, y=0.2, z=0}), "advtrains_interlocking:tcbmarker")
 	if not obj then return end
diff --git a/advtrains_interlocking/signal_aspect_accessors.lua b/advtrains_interlocking/signal_aspect_accessors.lua
index e419515..d91df31 100644
--- a/advtrains_interlocking/signal_aspect_accessors.lua
+++ b/advtrains_interlocking/signal_aspect_accessors.lua
@@ -1,33 +1,12 @@
 --- Signal aspect accessors
 -- @module advtrains.interlocking
 
-local A = advtrains.interlocking.aspects
+local A = advtrains.interlocking.aspect
 local D = advtrains.distant
 local I = advtrains.interlocking
 local N = advtrains.ndb
 local pts = advtrains.roundfloorpts
 
-local signal_aspect_metatable = {
-	__tostring = function(asp)
-		local st = {}
-		if asp.type2group and asp.type2name then
-			table.insert(st, string.format("%q in group %q", asp.type2name, asp.type2group))
-		end
-		if asp.main then
-			table.insert(st, string.format("current %d", asp.main))
-		end
-		if asp.main ~= 0 then
-			if asp.dst then
-				table.insert(st, string.format("next %d", asp.dst))
-			end
-			if asp.proceed_as_main then
-				table.insert(st, "proceed as main")
-			end
-		end
-		return string.format("[%s]", table.concat(st, ", "))
-	end,
-}
-
 local get_aspect
 
 local supposed_aspects = {}
@@ -37,9 +16,9 @@ local supposed_aspects = {}
 -- @param db The new database.
 function I.load_supposed_aspects(tbl)
 	if tbl then
-		supposed_aspects = tbl
-		for _, v in pairs(tbl) do
-			setmetatable(v, signal_aspect_metatable)
+		supposed_aspects = {}
+		for k, v in pairs(tbl) do
+			supposed_aspects[k] = A(v)
 		end
 	end
 end
@@ -48,7 +27,11 @@ end
 -- @function save_supposed_aspects
 -- @return The current database in use.
 function I.save_supposed_aspects()
-	return supposed_aspects
+	local t = {}
+	for k, v in pairs(supposed_aspects) do
+		t[k] = v:plain(true)
+	end
+	return t
 end
 
 --- Read the aspect of a signal strictly from cache.
@@ -72,7 +55,7 @@ end
 -- @return[2] An empty table (otherwise).
 local function get_ndef(pos)
 	local node = N.get_node(pos)
-	return minetest.registered_nodes[node.name] or {}
+	return (minetest.registered_nodes[node.name] or {}), node
 end
 
 --- Get the aspects supported by a signal.
@@ -94,43 +77,18 @@ end
 -- @return The adjusted signal aspect.
 -- @return The information to pass to the `advtrains.set_aspect` field in the node definitions.
 local function adjust_aspect(pos, asp)
-	asp = table.copy(I.signal_convert_aspect_if_necessary(asp))
-	setmetatable(asp, signal_aspect_metatable)
+	local asp = A(asp)
 
 	local mainpos = D.get_main(pos)
 	local nxtasp
 	if mainpos then
 		nxtasp = get_aspect(mainpos)
 	end
-	if asp.main ~= 0 and mainpos then
-		asp.dst = nxtasp.main
-	else
-		asp.dst = nil
-	end
-
 	local suppasp = get_supported_aspects(pos)
 	if not suppasp then
-		return asp, asp
-	end
-	local stype = suppasp.type
-	if stype == 2 then
-		local group = suppasp.group
-		local name
-		if suppasp.dst_shift and nxtasp then
-			asp.main = nil
-			name = A.type1_to_type2main(nxtasp, group, suppasp.dst_shift)
-		elseif asp.main ~= 0 and nxtasp and nxtasp.type2group == group and nxtasp.type2name then
-			name = A.get_type2_dst(group, nxtasp.type2name)
-		else
-			name = A.type1_to_type2main(asp, group)
-		end
-		asp.type2group = group
-		asp.type2name = name
-		return asp, name
+		return asp
 	end
-	asp.type2name = nil
-	asp.type2group = nil
-	return asp, asp
+	return asp:adjust_distant(nxtasp, suppasp.dst_shift):to_group(suppasp.group)
 end
 
 --- Get the aspect of a signal without accessing the cache.
@@ -140,13 +98,9 @@ end
 -- @return[1] The signal aspect adjusted using `adjust_aspect` (if present).
 -- @return[2] The nil constant (otherwise).
 local function get_real_aspect(pos)
-	local ndef = get_ndef(pos)
+	local ndef, node = get_ndef(pos)
 	if ndef.advtrains and ndef.advtrains.get_aspect then
 		local asp = ndef.advtrains.get_aspect(pos, node) or I.DANGER
-		local suppasp = get_supported_aspects(pos)
-		if suppasp and suppasp.type == 2 then
-			asp = A.type2_to_type1(suppasp, asp)
-		end
 		return adjust_aspect(pos, asp)
 	end
 	return nil
@@ -176,11 +130,11 @@ local function set_aspect(pos, asp, skipdst)
 	local ndef = minetest.registered_nodes[node.name]
 	if ndef and ndef.advtrains and ndef.advtrains.set_aspect then
 		local oldasp = I.signal_get_aspect(pos) or DANGER
-		local newasp, aspval = adjust_aspect(pos, asp)
+		local newasp = adjust_aspect(pos, asp)
 		set_supposed_aspect(pos, newasp)
-		ndef.advtrains.set_aspect(pos, node, aspval)
+		ndef.advtrains.set_aspect(pos, node, newasp)
 		I.signal_on_aspect_changed(pos)
-		local aspect_changed = A.not_equalp(oldasp, newasp)
+		local aspect_changed = oldasp ~= newasp
 		if (not skipdst) and aspect_changed then
 			D.update_main(pos)
 		end
diff --git a/advtrains_interlocking/signal_aspect_ui.lua b/advtrains_interlocking/signal_aspect_ui.lua
index 186d2fe..d36c6bc 100644
--- a/advtrains_interlocking/signal_aspect_ui.lua
+++ b/advtrains_interlocking/signal_aspect_ui.lua
@@ -1,7 +1,7 @@
 local F = advtrains.formspec
 local players_aspsel = {}
 
-local function describe_t1_main_aspect(spv)
+local function describe_main_aspect(spv)
 	if spv == 0 then
 		return attrans("Danger (halt)")
 	elseif spv == -1 then
@@ -13,7 +13,7 @@ local function describe_t1_main_aspect(spv)
 	end
 end
 
-local function describe_t1_shunt_aspect(shunt)
+local function describe_shunt_aspect(shunt)
 	if shunt then
 		return attrans("Shunting allowed")
 	else
@@ -21,7 +21,7 @@ local function describe_t1_shunt_aspect(shunt)
 	end
 end
 
-local function describe_t1_distant_aspect(spv)
+local function describe_distant_aspect(spv)
 	if spv == 0 then
 		return attrans("Expect to stop at the next signal")
 	elseif spv == -1 then
@@ -33,9 +33,9 @@ local function describe_t1_distant_aspect(spv)
 	end
 end
 
-advtrains.interlocking.describe_t1_main_aspect = describe_t1_main_aspect
-advtrains.interlocking.describe_t1_shunt_aspect = describe_t1_shunt_aspect
-advtrains.interlocking.describe_t1_distant_aspect = describe_t1_distant_aspect
+advtrains.interlocking.describe_main_aspect = describe_main_aspect
+advtrains.interlocking.describe_shunt_aspect = describe_shunt_aspect
+advtrains.interlocking.describe_distant_aspect = describe_distant_aspect
 
 local function dsel(p, q, x, y)
 	if p == nil then
@@ -51,19 +51,23 @@ local function dsel(p, q, x, y)
 	end
 end
 
-local function describe_supported_aspects_t1(suppasp, isasp)
+local function describe_supported_aspects(suppasp, isasp)
 	local t = {}
 
-	local entries = {}
-	local selid = 1
-	for idx, spv in ipairs(suppasp.main) do
-		if isasp and spv == (isasp.main or false) then
+	local entries = {attrans("Use default value")}
+	local selid = 0
+	local mainasps = suppasp.main
+	if type(mainasps) ~= "table" then
+		mainasps = {mainasps or false}
+	end
+	for idx, spv in ipairs(mainasps) do
+		if isasp and spv == rawget(isasp, "main") then
 			selid = idx
 		end
-		entries[idx] = describe_t1_main_aspect(spv)
+		entries[idx+1] = describe_main_aspect(spv)
 	end
 	t.main = entries
-	t.main_current = selid
+	t.main_current = selid+1
 	t.main_string = tostring(isasp.main)
 	if t.main == nil then
 		t.main_string = ""
@@ -83,21 +87,21 @@ local function describe_supported_aspects_t1(suppasp, isasp)
 
 	entries = {}
 	selid = 1
-	for idx, spv in ipairs(suppasp.dst) do
+	for idx, spv in ipairs(suppasp.dst or {}) do
 		if isasp and spv == (isasp.dst or false) then
 			selid = idx
 		end
-		entries[idx] = describe_t1_distant_aspect(spv)
+		entries[idx] = describe_distant_aspect(spv)
 	end
 	t.dst = entries
 	t.dst_current = selid
 	return t
 end
 
-advtrains.interlocking.describe_supported_aspects_t1 = describe_supported_aspects_t1
+advtrains.interlocking.describe_supported_aspects = describe_supported_aspects
 
-local function make_signal_aspect_selector_t1(suppasp, purpose, isasp)
-	local t = describe_supported_aspects_t1(suppasp, isasp)
+local function make_signal_aspect_selector(suppasp, purpose, isasp)
+	local t = describe_supported_aspects(suppasp, isasp)
 	local formmode = 1
 
 	local pos
@@ -142,55 +146,6 @@ local function make_signal_aspect_selector_t1(suppasp, purpose, isasp)
 	return table.concat(form)
 end
 
-local function make_signal_aspect_selector_t2(suppasp, purpose, isasp)
-	local def = advtrains.interlocking.aspects.get_type2_definition(suppasp.group)
-	if not def then
-		return nil
-	end
-	local formmode = 1
-
-	local pos
-	if type(purpose) == "table" then
-		formmode = 2
-		pos = purpose.pos
-	end
-	local form = {
-		"formspec_version[4]",
-		string.format("size[8,%f]", ({4.25, 10.25})[formmode]),
-		F.S_label(0.5, 0.5, "Select signal aspect")
-	}
-	if formmode == 1 then
-		form[#form+1] = F.label(0.5, 1, purpose)
-	else
-		form[#form+1] = F.S_label(0.5, 1, "Signal at @1", minetest.pos_to_string(pos))
-	end
-
-	local entries = {}
-	local selid = #def.main
-	if isasp then
-		if isasp.type2name ~= def.main[selid].name then
-			selid = 1
-		end
-	end
-	if selid > 1 then
-		selid = 2
-	end
-	local entries = {
-		def.main[1].label,
-		def.main[#def.main].label,
-	}
-	form[#form+1] = F.S_label(0.5, 1.5, "Signal group: @1", def.label)
-	form[#form+1] = F.dropdown(0.5, 2, 7, "asp_sel", entries, selid, true)
-	form[#form+1] = F.S_button_exit(0.5, 3, 7, "asp_save", "Save signal aspect")
-
-	if formmode == 2 then
-		form[#form+1] = advtrains.interlocking.make_ip_formspec_component(pos, 0.5, 4, 7)
-		form[#form+1] = advtrains.interlocking.make_dst_formspec_component(pos, 0.5, 5.5, 7, 4.25)
-	end
-
-	return table.concat(form)
-end
-
 function advtrains.interlocking.show_signal_aspect_selector(pname, p_suppasp, p_purpose, callback, isasp)
 	local suppasp = p_suppasp or {
 		main = {0, -1},
@@ -205,18 +160,7 @@ function advtrains.interlocking.show_signal_aspect_selector(pname, p_suppasp, p_
 		purpose = {pname = pname, pos = pos}
 	end
 
-	local form
-	if suppasp.type == 2 then
-		if suppasp.dst_shift then
-			if pos then
-				advtrains.interlocking.show_ip_form(pos, pname)
-			end
-			return
-		end
-		form = make_signal_aspect_selector_t2(suppasp, purpose, isasp)
-	else
-		form = make_signal_aspect_selector_t1(suppasp, purpose, isasp)
-	end
+	local form = make_signal_aspect_selector(suppasp, purpose, isasp)
 	if not form then
 		return
 	end
@@ -241,9 +185,9 @@ local function usebool(sup, val, free)
 	end
 end
 
-local function get_aspect_from_formspec_t1(suppasp, fields, psl)
+local function get_aspect_from_formspec(suppasp, fields, psl)
 	local maini = tonumber(fields.asp_mainsel)
-	local main = suppasp.main[maini]
+	local main = suppasp.main[(maini or 0)-1]
 	if not maini then
 		local mainval = fields.asp_mainval
 		if mainval == "-1" then
@@ -253,6 +197,8 @@ local function get_aspect_from_formspec_t1(suppasp, fields, psl)
 		else
 			main = nil
 		end
+	elseif maini <= 1 then
+		main = nil
 	end
 	local shunti = tonumber(fields.asp_shunt)
 	local shunt = suppasp.shunt
@@ -271,19 +217,6 @@ local function get_aspect_from_formspec_t1(suppasp, fields, psl)
 	}
 end
 
-local function get_aspect_from_formspec_t2(suppasp, fields, psl)
-	local sel = tonumber(fields.asp_sel)
-	local def = advtrains.interlocking.aspects.get_type2_definition(suppasp.group)
-	if not (sel and def) then
-		return
-	end
-	if sel ~= 1 then
-		sel = #def.main
-	end
-	local asp = advtrains.interlocking.aspects.type2_to_type1(suppasp, sel)
-	return asp
-end
-
 minetest.register_on_player_receive_fields(function(player, formname, fields)
 	local pname = player:get_player_name()
 	local psl = players_aspsel[pname]
@@ -292,11 +225,7 @@ minetest.register_on_player_receive_fields(function(player, formname, fields)
 			local suppasp = psl.suppasp
 			if fields.asp_save then
 				local asp
-				if suppasp.type == 2 then
-					asp = get_aspect_from_formspec_t2(suppasp, fields, psl)
-				else
-					asp = get_aspect_from_formspec_t1(suppasp, fields, psl)
-				end
+				asp = get_aspect_from_formspec(suppasp, fields, psl)
 				if asp then
 					psl.callback(pname, asp)
 				end
diff --git a/advtrains_interlocking/signal_aspects.lua b/advtrains_interlocking/signal_aspects.lua
deleted file mode 100644
index 14e04c7..0000000
--- a/advtrains_interlocking/signal_aspects.lua
+++ /dev/null
@@ -1,202 +0,0 @@
---- Signal aspect handling.
--- @module advtrains.interlocking.aspects
-
-local type2defs = {}
-
---- Register a type 2 signal group.
--- @function register_type2
--- @param def The definition table.
-local function register_type2(def)
-	local t = {type = 2}
-	local name = def.name
-	if type(name) ~= "string" then
-		return error("Name is not a string")
-	elseif type2defs[name] then
-		return error(string.format("Attempt to redefine type 2 signal aspect group %q, previously defined in %s", name, type2defs[name].defined))
-	end
-	t.name = name
-
-	t.defined = debug.getinfo(2, "S").short_src or "[?]"
-
-	local label = def.label or name
-	if type(label) ~= "string" then
-		return error("Label is not a string")
-	end
-	t.label = label
-
-	local mainasps = {}
-	for idx, asp in ipairs(def.main) do
-		local t = {}
-		local name = asp.name
-		if type(name) ~= "string" then
-			return error("Aspect name is not a string")
-		end
-		t.name = name
-
-		local label = asp.label or name
-		if type(label) ~= "string" then
-			return error("Aspect label is not a string")
-		end
-		t.label = label
-
-		t.main = asp.main
-		t.shunt = asp.shunt
-		t.proceed_as_main = asp.proceed_as_main
-		mainasps[idx] = t
-		mainasps[name] = idx
-	end
-	t.main = mainasps
-
-	type2defs[name] = t
-end
-
---- Get the definition of a type 2 signal group.
--- @function get_type2_definition
--- @param name The name of the signal group.
--- @return[1] The definition for the signal group (if present).
--- @return[2] The nil constant (otherwise).
-local function get_type2_definition(name)
-	local t = type2defs[name]
-	if t then
-		return table.copy(t)
-	else
-		return nil
-	end
-end
-
---- Get the name of the distant aspect before the current aspect.
--- @function get_type2_dst
--- @param group The name of the group.
--- @param name The name of the current aspect.
--- @return[1] The name of the distant aspect (if present).
--- @return[2] The nil constant (otherwise).
-local function get_type2_dst(group, name)
-	local def = type2defs[group]
-	if not def then
-		return nil
-	end
-	local aspidx = name
-	if type(name) ~= "number" then
-		aspidx = def.main[name] or 1
-	end
-	return def.main[math.max(1, aspidx-1)].name
-end
-
---- Convert a type 2 signal aspect to a type 1 signal aspect.
--- @function type2_to_type1
--- @param suppasp The table of supported aspects for the signal.
--- @param asp The name of the signal aspect.
--- @return[1] The type 1 signal aspect table (if present).
--- @return[2] The nil constant (otherwise).
-local function type2_to_type1(suppasp, asp)
-	local name = suppasp.group
-	local shift = suppasp.dst_shift
-	local def = type2defs[name]
-	if not def then
-		return nil
-	end
-	local aspidx
-	if type(asp) == "number" then
-		aspidx = asp
-	else
-		aspidx = def.main[asp] or 2
-	end
-	local realidx = math.min(#def.main, aspidx+(shift or 0))
-	local asptbl = def.main[realidx]
-	if not asptbl then
-		return nil
-	end
-	if type(asp) == "number" then
-		asp = asptbl.name
-	end
-	local main, shunt, dst
-	if shift then
-		dst = asptbl.main
-	else
-		main = asptbl.main
-		shunt = asptbl.shunt
-		dst = def.main[math.min(#def.main, aspidx+1)].main
-	end
-	if main == 0 then
-		dst = nil
-	end
-
-	local t = {
-		main = main,
-		shunt = shunt,
-		proceed_as_main = asptbl.proceed_as_main,
-		type2name = asptbl.name,
-		type2group = name,
-		dst = dst,
-	}
-	if aspidx > 1 and aspidx < #asptbl then
-		t.dst = asptbl[aspidx+1].main
-	end
-	return t
-end
-
---- Convert a type 1 signal aspect table to a type 2 signal aspect.
--- @function type1_to_type2main
--- @param asp The type 1 signal aspect table
--- @param group The signal aspect group
--- @param[opt=0] shift The shift for the signal aspect.
--- @return[1] The name of the signal aspect (if present).
--- @return[2] The nil constant (otherwise).
-local function type1_to_type2main(asp, group, shift)
-	local def = type2defs[group]
-	if not def then
-		return nil
-	end
-	local t_main = def.main
-	local idx
-	if group == asp.type2group and t_main[asp.type2name] then
-		idx = t_main[asp.type2name]
-	elseif not asp.main or asp.main == -1 then
-		idx = 1
-	elseif asp.main == 0 then
-		idx = #t_main
-	else
-		idx = #t_main-1
-	end
-	return t_main[math.max(1, idx-(shift or 0))].name
-end
-
---- Compare two type 1 signal aspect tables.
--- @function equalp
--- @param asp1 The first signal aspect table.
--- @param asp2 The second signal aspect table.
--- @return Whether the two signal aspect tables give the same (type 1 aspect) information.
-local function equalp(asp1, asp2)
-	if asp1 == asp2 then -- same reference
-		return true
-	else
-		for _, k in pairs {"main", "shunt", "dst"} do
-			if asp1[k] ~= asp2[k] then
-				return false
-			end
-		end
-	end
-	if asp1.type2group and asp1.type2group == asp2.type2group then
-		return asp1.type2name == asp2.type2name
-	end
-	return true
-end
-
---- Compare two signal aspect tables.
--- @function not_equalp
--- @param asp1 The first signal aspect table.
--- @param asp2 The second signal aspect table.
--- @return The negation of `equalp``(asp1, asp2)`.
-local function not_equalp(asp1, asp2)
-	return not equalp(asp1, asp2)
-end
-
-return {
-	register_type2 = register_type2,
-	get_type2_definition = get_type2_definition,
-	get_type2_dst = get_type2_dst,
-	type2_to_type1 = type2_to_type1,
-	type1_to_type2main = type1_to_type2main,
-	equalp = equalp,
-	not_equalp = not_equalp,
-}
diff --git a/advtrains_interlocking/spec/basic_signalling_spec.lua b/advtrains_interlocking/spec/basic_signalling_spec.lua
index cce0f15..a4e1e3a 100644
--- a/advtrains_interlocking/spec/basic_signalling_spec.lua
+++ b/advtrains_interlocking/spec/basic_signalling_spec.lua
@@ -8,7 +8,7 @@ mineunit("core")
 
 _G.advtrains = {
 	interlocking = {
-		aspects = fixture("../../signal_aspects"),
+		aspect = fixture("../../aspect"),
 	},
 	ndb = {
 		get_node = minetest.get_node,
@@ -31,12 +31,16 @@ minetest.register_node("advtrains_interlocking:signal_sign", {
 
 local D = advtrains.distant
 local I = advtrains.interlocking
+local A = I.aspect
 
 local stub_aspect_t1 = {
 	free = {main = -1},
 	slow = {main = 6},
 	danger = {main = 0, shunt = false},
 }
+for k, v in pairs(stub_aspect_t1) do
+	stub_aspect_t1[k] = A(v)
+end
 local stub_pos_t1 = {}
 for i = 1, 4 do
 	stub_pos_t1[i] = {x = 1, y = 0, z = i}
@@ -55,14 +59,14 @@ describe("API for supposed signal aspects", function()
 		I.load_supposed_aspects(tbl)
 		assert.same(tbl, I.save_supposed_aspects())
 	end)
-	it("should set and get type 1 signals properly", function ()
+	it("should set and get signals properly", function ()
 		local pos = stub_pos_t1[2]
 		local asp = stub_aspect_t1.slow
-		local newasp = { main = math.random(1,5) }
-		assert.same(asp, I.signal_get_aspect(pos))
+		local newasp = A{ main = math.random(1,5) }
+		assert.equal(asp, I.signal_get_aspect(pos))
 		I.signal_set_aspect(pos, newasp)
-		assert.same(newasp, I.signal_get_aspect(pos))
-		assert.same(asp, I.signal_get_real_aspect(pos))
+		assert.equal(newasp, I.signal_get_aspect(pos))
+		assert.equal(asp, I.signal_get_real_aspect(pos))
 		I.signal_set_aspect(pos, asp)
 	end)
 end)
@@ -72,9 +76,9 @@ describe("Distant signaling", function()
 		for i = 1, 2 do
 			D.assign(stub_pos_t1[i], stub_pos_t1[i+1])
 		end
-		assert.same(stub_aspect_t1.danger, I.signal_get_aspect(stub_pos_t1[1]))
-		assert.same({main = 6, dst = 0}, I.signal_get_aspect(stub_pos_t1[2]))
-		assert.same({main = -1, dst = 6}, I.signal_get_aspect(stub_pos_t1[3]))
+		assert.equal(stub_aspect_t1.danger, I.signal_get_aspect(stub_pos_t1[1]))
+		assert.equal(A{main = 6, dst = 0}, I.signal_get_aspect(stub_pos_t1[2]))
+		assert.equal(A{main = -1, dst = 6}, I.signal_get_aspect(stub_pos_t1[3]))
 	end)
 	it("should report assignments properly", function()
 		assert.same({stub_pos_t1[1], "manual"}, {D.get_main(stub_pos_t1[2])})
@@ -82,8 +86,8 @@ describe("Distant signaling", function()
 	end)
 	it("should update distant aspects automatically", function()
 		I.signal_set_aspect(stub_pos_t1[2], {main = 2, dst = -1})
-		assert.same({main = 2, dst = 0}, I.signal_get_aspect(stub_pos_t1[2]))
-		assert.same({main = -1, dst = 2}, I.signal_get_aspect(stub_pos_t1[3]))
+		assert.equal(A{main = 2, dst = 0}, I.signal_get_aspect(stub_pos_t1[2]))
+		assert.equal(A{main = -1, dst = 2}, I.signal_get_aspect(stub_pos_t1[3]))
 	end)
 	it("should unassign signals when one is removed", function()
 		world.set_node(stub_pos_t1[2], "air")
diff --git a/advtrains_interlocking/spec/signal_group_spec.lua b/advtrains_interlocking/spec/signal_group_spec.lua
new file mode 100644
index 0000000..bc9d007
--- /dev/null
+++ b/advtrains_interlocking/spec/signal_group_spec.lua
@@ -0,0 +1,95 @@
+require "mineunit"
+mineunit("core")
+
+_G.advtrains = {
+	interlocking = {
+		aspect = sourcefile("aspect"),
+	},
+	ndb = {
+		get_node = minetest.get_node,
+		swap_node = minetest.swap_node,
+	}
+}
+
+fixture("advtrains_helpers")
+sourcefile("database")
+sourcefile("signal_api")
+sourcefile("distant")
+sourcefile("signal_aspect_accessors")
+
+local A = advtrains.interlocking.aspect
+local D = advtrains.distant
+local I = advtrains.interlocking
+local N = advtrains.ndb
+
+local groupdef = {
+	name = "foo",
+	aspects = {
+		proceed = {main = -1},
+		caution = {},
+		danger = {main = 0},
+		"proceed",
+		{"caution"},
+		"danger",
+	},
+}
+
+for k, v in pairs(groupdef.aspects) do
+	minetest.register_node("advtrains_interlocking:" .. k, {
+		advtrains = {
+			supported_aspects = {
+				group = "foo",
+			},
+			get_aspect = function() return A{group = "foo", name = k} end,
+			set_aspect = function(pos, _, name)
+				N.swap_node(pos, {name = "advtrains_interlocking:" .. name})
+			end,
+		}
+	})
+end
+
+local origin = vector.new(0, 0, 0)
+local dstpos = vector.new(0, 0, 1)
+
+world.layout {
+	{origin, "advtrains_interlocking:danger"},
+	{dstpos, "advtrains_interlocking:proceed"},
+}
+
+describe("signal group registration", function()
+	it("should work", function()
+		A.register_group(groupdef)
+		assert(A.get_group_definition("foo"))
+	end)
+	it("should only be allowed once for the same group", function()
+		assert.has.errors(function() A.register_group(type2def) end)
+	end)
+	it("should handle nonexistant groups", function()
+		assert.is_nil(A.get_group_definition("something_else"))
+	end)
+	it("should reject invalid definitions", function()
+		assert.has.errors(function() A.register_group({}) end)
+		assert.has.errors(function() A.register_group({name="",label={}}) end)
+		assert.has.errors(function() A.register_group({name="",aspects={}}) end)
+	end)
+end)
+
+describe("signal aspect", function()
+	it("should handle empty fields properly", function()
+		assert.equal(A{main = 0}, A{group="foo", name="danger"}:to_group())
+	end)
+	it("should be converted properly", function()
+		assert.equal(A{main = 0}, A{group="foo", name="danger"})
+		assert.equal(A{}, A{group="foo", name="caution"})
+		assert.equal(A{main = -1}, A{group="foo", name="proceed"})
+	end)
+end)
+
+describe("signals in groups", function()
+	it("should support distant signaling", function()
+		assert.equal("caution", A():adjust_distant(A{group="foo",name="danger"}).name)
+		assert.equal("proceed", A():adjust_distant(A{group="foo",name="caution"}).name)
+		assert.equal("proceed", A():adjust_distant(A{group="foo",name="proceed"}).name)
+		assert.equal("danger", A{group="foo",name="danger"}:adjust_distant{}.name)
+	end)
+end)
diff --git a/advtrains_interlocking/spec/type2_spec.lua b/advtrains_interlocking/spec/type2_spec.lua
deleted file mode 100644
index ac23574..0000000
--- a/advtrains_interlocking/spec/type2_spec.lua
+++ /dev/null
@@ -1,117 +0,0 @@
-require "mineunit"
-mineunit("core")
-
-_G.advtrains = {
-	interlocking = {
-		aspects = sourcefile("signal_aspects"),
-	},
-	ndb = {
-		get_node = minetest.get_node,
-		swap_node = minetest.swap_node,
-	}
-}
-
-fixture("advtrains_helpers")
-sourcefile("database")
-sourcefile("signal_api")
-sourcefile("distant")
-sourcefile("signal_aspect_accessors")
-
-local A = advtrains.interlocking.aspects
-local D = advtrains.distant
-local I = advtrains.interlocking
-local N = advtrains.ndb
-
-local type2def = {
-	name = "foo",
-	main = {
-		{name = "proceed", main = -1},
-		{name = "caution"},
-		{name = "danger", main = 0},
-	},
-}
-
-for _, v in pairs(type2def.main) do
-	minetest.register_node("advtrains_interlocking:" .. v.name, {
-		advtrains = {
-			supported_aspects = {
-				type = 2,
-				group = "foo",
-			},
-			get_aspect = function() return v.name end,
-			set_aspect = function(pos, _, name)
-				N.swap_node(pos, {name = "advtrains_interlocking:" .. name})
-			end,
-		}
-	})
-end
-
-local function asp(group, name, dst)
-	return A.type2_to_type1({group = group, dst_shift = shift}, name)
-end
-
-local origin = vector.new(0, 0, 0)
-local dstpos = vector.new(0, 0, 1)
-
-world.layout {
-	{origin, "advtrains_interlocking:danger"},
-	{dstpos, "advtrains_interlocking:proceed"},
-}
-
-describe("type 2 signal group registration", function()
-	it("should work", function()
-		A.register_type2(type2def)
-		assert(A.get_type2_definition("foo"))
-	end)
-	it("should only be allowed once for the same group", function()
-		assert.has.errors(function() A.register_type2(type2def) end)
-	end)
-	it("should handle nonexistant groups", function()
-		assert.is_nil(A.get_type2_definition("something_else"))
-	end)
-	it("should reject invalid definitions", function()
-		assert.has.errors(function() A.register_type2({}) end)
-		assert.has.errors(function() A.register_type2({name="",label={}}) end)
-		assert.has.errors(function() A.register_type2({name="",main={{name={}}}}) end)
-		assert.has.errors(function() A.register_type2({name="",main={{name="",label={}}}}) end)
-	end)
-end)
-
-describe("signal aspect conversion", function()
-	it("should work for converting from type 1 to type 2", function()
-		assert.equal("danger", A.type1_to_type2main({main = 0}, "foo"))
-		assert.equal("caution", A.type1_to_type2main({main = 6}, "foo"))
-		assert.equal("proceed", A.type1_to_type2main({}, "foo"))
-	end)
-	it("should reject invalid type 2 signal information", function()
-		assert.is_nil(A.type1_to_type2main({}, "?"))
-		assert.is_nil(A.type2_to_type1({}, "x"))
-		assert.same(asp("foo","caution"), asp("foo", "x"))
-	end)
-	it("should accept integer indices for type 2 signal aspects", function()
-		assert.same(asp("foo", "caution"), asp("foo", 2))
-		assert.same(asp("foo", "danger"), asp("foo", 10))
-		assert.same(asp("foo", "proceed"), asp("foo", 1))
-		assert.is_nil(asp("foo", -0.5))
-	end)
-end)
-
-describe("type 2 signals", function()
-	it("should support distant signaling", function()
-		assert.equal("caution", A.get_type2_dst("foo", 3))
-		assert.equal("proceed", A.get_type2_dst("foo", "caution"))
-		assert.equal("proceed", A.get_type2_dst("foo", "proceed"))
-	end)
-	it("should work with accessors", function()
-		assert.same(asp("foo","danger"), I.signal_get_aspect(origin))
-		local newasp = {type2group = "foo", type2name = "proceed", main = 6}
-		I.signal_set_aspect(origin, newasp)
-		assert.same(newasp, I.signal_get_aspect(origin))
-	end)
-	it("should work with distant signaling", function()
-		assert.same(asp("foo","proceed"), I.signal_get_aspect(dstpos))
-		local dstasp = {type2group = "foo", type2name = "proceed", dst = 6, main = -1}
-		D.assign(origin, dstpos)
-		assert.same(dstasp, I.signal_get_aspect(dstpos))
-	end)
-end)
diff --git a/advtrains_signals_japan/init.lua b/advtrains_signals_japan/init.lua
index fe74259..7d8dc1e 100644
--- a/advtrains_signals_japan/init.lua
+++ b/advtrains_signals_japan/init.lua
@@ -291,10 +291,10 @@ local aspnames = {
 }
 local function process_signal(name, sigdata, isrpt)
 	local typename = "advtrains_signals_japan:" .. name
-	local type2def = {}
-	type2def.name = typename
-	type2def.main = {}
-	type2def.label = S(string.format("Japanese signal (type %s)", string.upper(name)))
+	local groupdef = {}
+	groupdef.name = typename
+	groupdef.aspects = {}
+	groupdef.label = S(string.format("Japanese signal (type %s)", string.upper(name)))
 	local def = {}
 	local tx = {}
 	def.typename = typename
@@ -322,7 +322,8 @@ local function process_signal(name, sigdata, isrpt)
 			tt[#tt+1] = string.format("0,%d=(advtrains_hud_bg.png\\^[colorize\\:%s)", lightcount-1, color)
 		end
 		tx[aspname] = table.concat(tt, ":")
-		type2def.main[idx] = {name = asp.name, label = S(aspnames[asp.name]), main = asp.main, proceed_as_main = true}
+		groupdef.aspects[idx] = {asp.name}
+		groupdef.aspects[asp.name] = {label = S(aspnames[asp.name]), main = asp.main, proceed_as_main = true}
 	end
 	local invimg = {
 		string.format("[combine:%dx%d", lightcount*4+1, lightcount*4+1),
@@ -337,7 +338,7 @@ local function process_signal(name, sigdata, isrpt)
 	end
 	def.inventory_image = table.concat(invimg, ":")
 	if not isrpt then
-		advtrains.interlocking.aspects.register_type2(type2def)
+		advtrains.interlocking.aspect.register_group(groupdef)
 	end
 	return def
 end
@@ -400,15 +401,14 @@ for _, rtab in ipairs {
 				drop = "advtrains_signals_japan:"..sigtype.."_danger_0",
 				advtrains = {
 					supported_aspects = {
-						type = 2,
 						group = siginfo.typename,
 						dst_shift = siginfo.isdst and 0,
 					},
 					get_aspect = function()
-						return asp
+						return {group = siginfo.typename, name = asp}
 					end,
 					set_aspect = function(pos, node, asp)
-						advtrains.ndb.swap_node(pos, {name = "advtrains_signals_japan:"..sigtype.."_"..asp.."_"..rot, param2 = node.param2})
+						advtrains.ndb.swap_node(pos, {name = "advtrains_signals_japan:"..sigtype.."_"..(asp.name).."_"..rot, param2 = node.param2})
 					end,
 				},
 				on_rightclick = advtrains.interlocking.signal_rc_handler,
-- 
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