Merge branch 'master' into cesky-hvozd

Throw away most of the changes in everything except line_automation.
Merge line_automation changes between CH and master

1 files changed, 273 insertions, 273 deletions

diff --git a/advtrains/tracks.lua b/advtrains/tracks.lua
index dba0d7a..fa7b702 100644
--- a/advtrains/tracks.lua
+++ b/advtrains/tracks.lua
@@ -1,273 +1,273 @@
--- tracks.lua
--- rewritten with advtrains 2.5 according to new track registration system
-
-
---[[
-
-Tracks in advtrains are defined by the node definition. They must have at least 2 connections, but can have any number.
-Switchable nodes (turnouts, single/double-slip switches) are implemented by having a separate node (node name) for each of the possible states.
-
-	minetest.register_node(nodename, {
-	... usual node definition ...
-	groups = {
-		advtrains_track = 1,
-		advtrains_track_<tracktype>=1
-		^- these groups tell that the node is a track
-		not_blocking_trains=1,
-		^- this group tells that the node should not block trains although it's walkable.
-	},
-	
-	at_rail_y = 0,
-	^- Height of this rail node (the y position of a wagon that stands centered on this rail)
-	at_conns = {
-		  [1] = { c=0..15, y=0..1 },
-		  [2] = { c=0..15, y=0..1 },
-		( [3] = { c=0..15, y=0..1 }, )
-		( [4] = { c=0..15, y=0..1 }, )
-		( ... )
-	}
-	^- Connections of this rail. There are two general cases:
-	   a) SIMPLE TRACK - the track has exactly 2 connections, and does not feature a turnout, crossing or other contraption
-	      For simple tracks, except for the at_conns table no further setup needs to be specified. A train entering on conn 1 will go out at conn 2 and vice versa.
-		  A track with only one connection defined is not permitted.
-	   b) COMPOUND TRACK - the track has more than 2 connections
-	      This will be used for turnouts and crossings. Tracks with more than 2 conns MUST define 'at_conn_map'.
-		  Switchable nodes, whose state can be changed (e.g. turnouts) MUST define a 'state_map' within the advtrains table as well.
-		  This differs from the behavior up until 2.4.2, where the conn mapping was fixed.
-	^- Connection definition:
-	   - c is the direction of the connection (0-16). For the mapping to world directions see helpers.lua.
-	   - Connections will be auto-rotated with param2 of the node (horizontal, param2 values 0-3 only)
-	   - y is the height of the connection (rail will only connect when this matches)
-	^- The index of a connection inside the conns table (1, 2, 3, ...) is referred throughout advtrains code as 'connid'
-	^- IMPORTANT: For switchable nodes (any kind of turnout), it is crucial that for all of the node's variants the at_conns table stays the same. See below.
-	   
-	at_conn_map = {
-		[1] = 2,
-		[2] = 1,
-		[3] = 1,
-	}
-	^- Connection map of this rail. It specifies when a train enters the track on connid X, on which connid it will leave
-	   This field MUST be specified when the number of connections in at_conns is greater than 2
-	   This field may, and obviously will, vary between nodes for switchable nodes.
-	
-	can_dig = advtrains.track_can_dig_callback
-	after_dig_node = advtrains.track_update_callback
-	after_place_node = advtrains.track_update_callback
-	^- the code in these 3 default minetest API functions is required for advtrains to work, however you can add your own code
-	
-	on_rightclick = advtrains.state_node_on_rightclick_callback
-	^- Must be added if the node is a turnout and if it should be switched by right-click. It will cause the turnout to be switched to next_state.
-	
-	advtrains = {
-		on_train_enter=function(pos, train_id, train, index) end
-		^- called when a train enters the rail
-		on_train_leave=function(pos, train_id, train, index) end
-		^- called when a train leaves the rail
-		
-		-- The following function is only in effect when interlocking is enabled:
-		on_train_approach = function(pos, train_id, train, index, has_entered, lzbdata)
-		^- called when a train is approaching this position, called exactly once for every path recalculation (which can happen at any time)
-		^- This is called so that if the train would start braking now, it would come to halt about(wide approx) 5 nodes before the rail.
-		^- has_entered: when true, the train is already standing on this node with its front tip, and the enter callback has already been called.
-		   Possibly, some actions need not to be taken in this case. Only set if it's the very first node the train is standing on.
-		^- lzbdata should be ignored and nothing should be assigned to it
-		
-		-- The following information is required if the node is a turnout (e.g. can be switched into different positions)
-		node_state = "st"
-		^- The name of the state this node represents
-		^- Conventions for this field are as follows:
-		   - Two-way straight/turn switches: 'st'=straight branch, 'cr'=diverting/turn branch
-		   - 3-way turnouts, Y-turnouts: 'l'=left branch, 's'=straight branch, 'r'=right branch
-		   
-		node_next_state = "cr"
-		^- The name of the state that the turnout should be switched to when it is right-clicked
-		
-		node_fallback_state = "st"
-		^- The name of the state that the turnout should "fall back" to when it is released
-		   Only used by the interlocking system, when a route on the node is released it is switched back to this state.
-		
-		node_state_map = {
-			["st"] = "<node name of the st variant>",
-			["cr"] = "<node name of the cr variant>",
-			... etc ...
-		}
-		^- Map of state name to the appropriate node name that should be set by advtrains when a switch is requested
-		   Note that for all of those nodes, the at_conns table must be identical (however the conn_map will vary)
-		   
-		node_on_switch_state = function(pos, node, oldstate, newstate)
-		^- Called when the node state is switched by advtrains, after the node replacement has commenced.
-		
-		Turnout switching can happen programmatically via advtrains.setstate(pos, state), via user right_click or via the interlocking system.
-		In no other situation is it permissible to exchange track nodes in-place, unless both at_conns and at_conn_map stay identical.
-		
-		Note that the fields node_state, node_next_state and node_state_map completely replace the getstate/setstate functions.
-		There must be a one-to-one mapping between states and node names and no function can be defined for state switching.
-		This principle enables the seamless working of the interlocking autorouter and reduces failure points.
-		The node_state_* system can also be used as drop-in replacement for the passive-API-enabled nodes (andrews-cross, mesecon_switch etc.)
-		The advtrains API functions advtrains.getstate() and advtrains.setstate() remain the programmatic access points, but will now utilize the new state system.
-		
-		
-		trackworker_next_rot = <nodename of next rotation step>,
-		^- if set, right-click with trackworker will set this node
-		trackworker_rot_incr_param2 = true
-		^- if set, trackworker will increase node param2 on rightclick
-		
-		trackworker_next_var = <nodename of next variant>
-		^- if set, left-click with trackworker will set this node
-	}
-	})
-
-]]--
-
--- This file provides some utilities to register tracks, but tries to not get into the way too much
-
-
-function advtrains.track_can_dig_callback(pos, player)
-	local ok, reason = advtrains.can_dig_or_modify_track(pos)
-	if not ok and player then
-		minetest.chat_send_player(player:get_player_name(), attrans("This track can not be removed!") .. " " .. reason)
-	end
-	return ok
-end
-
-function advtrains.track_update_callback(pos)
-	advtrains.ndb.update(pos)
-end
-
-function advtrains.state_node_on_rightclick_callback(pos, node, player)
-	if advtrains.check_turnout_signal_protection(pos, player:get_player_name()) then
-		local ndef = minetest.registered_nodes[node.name]
-		if ndef and ndef.advtrains and ndef.advtrains.node_next_state then
-			advtrains.setstate(pos, ndef.advtrains.node_next_state, node)
-			advtrains.log("Switch", player:get_player_name(), pos)
-		end
-	end
-end
-
--- advtrains.register_node_4rot(name, nodedef)
--- Registers four rotations for the node defined by nodedef (0°, 30°, 45° and 60°; the 4 90°-steps are already handled by the param2, resulting in 16 directions total).
--- You must provide the definition for the base node, and certain fields are altered automatically for the 3 additional rotations:
---  name: appends the suffix "_30", "_45" or "_60"
---  description: appends the rotation (human-readable) in parenthesis
---  tiles_prefix: if defined, "tiles" field will be set as prefix..rotationExtension..".png"
---  mesh_prefix, mesh_suffix: if defined, "mesh" field will be set as prefix..rotationExtension..suffix
---  at_conns: are rotated according to the node rotation
---  node_state_map, trackworker_next_var: appends the suffix appropriately.
---  groups: applies save_in_at_nodedb and not_blocking_trains groups if not already present
--- The nodes are registered in the trackworker to be rotated with right-click.
--- definition_mangling_function is an optional parameter. For each of the 4 rotations, it gets passed the modified node definition and may perform final modifications to it.
---  signature: function definition_mangling_function(name, nodedef, rotationIndex, rotationSuffix)
---  Example usage: define the setstate function of turnouts (if that is not done via the "automatic" way of state_node_map)
-local rotations = {
-	{i = 0, s = "",    h = " (0)",  n = "_30"},
-	{i = 1, s = "_30", h = " (30)", n = "_45"},
-	{i = 2, s = "_45", h = " (45)", n = "_60"},
-	{i = 3, s = "_60", h = " (60)", n = ""},
-}
-function advtrains.register_node_4rot(ori_name, ori_ndef, definition_mangling_function)
-	for _, rot in ipairs(rotations) do
-		local ndef = table.copy(ori_ndef)
-		if ori_ndef.advtrains then
-			-- make sure advtrains table is deep-copied because we may need to replace node_state_map
-			ndef.advtrains = table.copy(ori_ndef.advtrains)
-		else
-			ndef.advtrains = {} -- we need the table later for trackworker
-		end
-		-- Perform the name mangling
-		local suffix = rot.s
-		local name = ori_name..suffix
-		ndef.description = ori_ndef.description .. rot.h
-		if ori_ndef.tiles_prefix then
-			ndef.tiles = { ori_ndef.tiles_prefix .. suffix .. ".png" }
-		end
-		if ori_ndef.mesh_prefix then
-			ndef.mesh = ori_ndef.mesh_prefix .. suffix .. ori_ndef.mesh_suffix
-		end
-		-- rotate connections
-		if ori_ndef.at_conns then
-			ndef.at_conns = advtrains.rotate_conn_by(ori_ndef.at_conns, rot.i)
-		end
-		-- update node state map if present
-		if ori_ndef.advtrains then
-			if ori_ndef.advtrains.node_state_map then
-				local new_nsm = {}
-				for state, nname in pairs(ori_ndef.advtrains.node_state_map) do
-					new_nsm[state] = nname .. suffix
-				end
-				ndef.advtrains.node_state_map = new_nsm
-			end
-			if ori_ndef.advtrains.trackworker_next_var then
-				ndef.advtrains.trackworker_next_var = ori_ndef.advtrains.trackworker_next_var .. suffix
-			end
-			-- apply trackworker rot field
-			ndef.advtrains.trackworker_next_rot = ori_name .. rot.n
-			ndef.advtrains.trackworker_rot_incr_param2 = (rot.n=="")
-		end
-		-- apply groups
-		ndef.groups.save_in_at_nodedb = 1
-		ndef.groups.not_blocking_trains = 1
-		
-		-- give the definition mangling function an option to do some adjustments
-		if definition_mangling_function then
-			definition_mangling_function(name, ndef, rot.i, suffix)
-		end
-		
-		-- register node
-		minetest.register_node(":"..name, ndef)
-		
-		-- if this has the track_place_group set, register as a candidate for the track_place_group
-		if ndef.advtrains.track_place_group then
-			advtrains.trackplacer.register_candidate(ndef.advtrains.track_place_group, name, ndef, ndef.advtrains.track_place_single, true)
-		end
-	end
-end
-
--- track-related helper functions
-
-function advtrains.is_track(nodename)
-	if not minetest.registered_nodes[nodename] then
-		return false
-	end
-	local nodedef=minetest.registered_nodes[nodename]
-	if nodedef and nodedef.groups.advtrains_track then
-		return true
-	end
-	return false
-end
-
--- returns the connection tables of the track with given node details
--- returns: conns table, railheight, conn_map table
-function advtrains.get_track_connections(name, param2)
-	local nodedef=minetest.registered_nodes[name]
-	if not nodedef then atprint(" get_track_connections couldn't find nodedef for nodename "..(name or "nil")) return nil end
-	local noderot=param2
-	if not param2 then noderot=0 end
-	if noderot > 3 then atprint(" get_track_connections: rail has invaild param2 of "..noderot) noderot=0 end
-	
-	if not nodedef.at_conns then
-		return nil
-	end
-	--atdebug("Track connections of ",name,param2,":",nodedef.at_conns)
-	return advtrains.rotate_conn_by(nodedef.at_conns, noderot*AT_CMAX/4), (nodedef.at_rail_y or 0), nodedef.at_conn_map
-end
-
--- Function called when a track is about to be dug or modified by the trackworker
--- Returns either true (ok) or false,"translated string describing reason why it isn't allowed"
--- Impl Note: possibly duplicate code in "self contained TCB" - see interlocking/tcb_ts_ui.lua!
-function advtrains.can_dig_or_modify_track(pos)
-	if advtrains.get_train_at_pos(pos) then
-		return false, attrans("Position is occupied by a train.")
-	end
-	-- interlocking: tcb, signal IP a.s.o.
-	if advtrains.interlocking then
-		-- TCB?
-		if advtrains.interlocking.db.get_tcb(pos) then
-			return false, attrans("There's a Track Circuit Break here.")
-		end
-		-- signal ip?
-		if advtrains.interlocking.db.is_ip_at(pos, true) then -- is_ip_at with purge parameter
-			return false, attrans("There's a Signal Influence Point here.")
-		end
-	end
-	return true
-end
+-- tracks.lua

+-- rewritten with advtrains 2.5 according to new track registration system

+

+

+--[[

+

+Tracks in advtrains are defined by the node definition. They must have at least 2 connections, but can have any number.

+Switchable nodes (turnouts, single/double-slip switches) are implemented by having a separate node (node name) for each of the possible states.

+

+	minetest.register_node(nodename, {

+	... usual node definition ...

+	groups = {

+		advtrains_track = 1,

+		advtrains_track_<tracktype>=1

+		^- these groups tell that the node is a track

+		not_blocking_trains=1,

+		^- this group tells that the node should not block trains although it's walkable.

+	},

+	

+	at_rail_y = 0,

+	^- Height of this rail node (the y position of a wagon that stands centered on this rail)

+	at_conns = {

+		  [1] = { c=0..15, y=0..1 },

+		  [2] = { c=0..15, y=0..1 },

+		( [3] = { c=0..15, y=0..1 }, )

+		( [4] = { c=0..15, y=0..1 }, )

+		( ... )

+	}

+	^- Connections of this rail. There are two general cases:

+	   a) SIMPLE TRACK - the track has exactly 2 connections, and does not feature a turnout, crossing or other contraption

+	      For simple tracks, except for the at_conns table no further setup needs to be specified. A train entering on conn 1 will go out at conn 2 and vice versa.

+		  A track with only one connection defined is not permitted.

+	   b) COMPOUND TRACK - the track has more than 2 connections

+	      This will be used for turnouts and crossings. Tracks with more than 2 conns MUST define 'at_conn_map'.

+		  Switchable nodes, whose state can be changed (e.g. turnouts) MUST define a 'state_map' within the advtrains table as well.

+		  This differs from the behavior up until 2.4.2, where the conn mapping was fixed.

+	^- Connection definition:

+	   - c is the direction of the connection (0-16). For the mapping to world directions see helpers.lua.

+	   - Connections will be auto-rotated with param2 of the node (horizontal, param2 values 0-3 only)

+	   - y is the height of the connection (rail will only connect when this matches)

+	^- The index of a connection inside the conns table (1, 2, 3, ...) is referred throughout advtrains code as 'connid'

+	^- IMPORTANT: For switchable nodes (any kind of turnout), it is crucial that for all of the node's variants the at_conns table stays the same. See below.

+	   

+	at_conn_map = {

+		[1] = 2,

+		[2] = 1,

+		[3] = 1,

+	}

+	^- Connection map of this rail. It specifies when a train enters the track on connid X, on which connid it will leave

+	   This field MUST be specified when the number of connections in at_conns is greater than 2

+	   This field may, and obviously will, vary between nodes for switchable nodes.

+	

+	can_dig = advtrains.track_can_dig_callback

+	after_dig_node = advtrains.track_update_callback

+	after_place_node = advtrains.track_update_callback

+	^- the code in these 3 default minetest API functions is required for advtrains to work, however you can add your own code

+	

+	on_rightclick = advtrains.state_node_on_rightclick_callback

+	^- Must be added if the node is a turnout and if it should be switched by right-click. It will cause the turnout to be switched to next_state.

+	

+	advtrains = {

+		on_train_enter=function(pos, train_id, train, index) end

+		^- called when a train enters the rail

+		on_train_leave=function(pos, train_id, train, index) end

+		^- called when a train leaves the rail

+		

+		-- The following function is only in effect when interlocking is enabled:

+		on_train_approach = function(pos, train_id, train, index, has_entered, lzbdata)

+		^- called when a train is approaching this position, called exactly once for every path recalculation (which can happen at any time)

+		^- This is called so that if the train would start braking now, it would come to halt about(wide approx) 5 nodes before the rail.

+		^- has_entered: when true, the train is already standing on this node with its front tip, and the enter callback has already been called.

+		   Possibly, some actions need not to be taken in this case. Only set if it's the very first node the train is standing on.

+		^- lzbdata should be ignored and nothing should be assigned to it

+		

+		-- The following information is required if the node is a turnout (e.g. can be switched into different positions)

+		node_state = "st"

+		^- The name of the state this node represents

+		^- Conventions for this field are as follows:

+		   - Two-way straight/turn switches: 'st'=straight branch, 'cr'=diverting/turn branch

+		   - 3-way turnouts, Y-turnouts: 'l'=left branch, 's'=straight branch, 'r'=right branch

+		   

+		node_next_state = "cr"

+		^- The name of the state that the turnout should be switched to when it is right-clicked

+		

+		node_fallback_state = "st"

+		^- The name of the state that the turnout should "fall back" to when it is released

+		   Only used by the interlocking system, when a route on the node is released it is switched back to this state.

+		

+		node_state_map = {

+			["st"] = "<node name of the st variant>",

+			["cr"] = "<node name of the cr variant>",

+			... etc ...

+		}

+		^- Map of state name to the appropriate node name that should be set by advtrains when a switch is requested

+		   Note that for all of those nodes, the at_conns table must be identical (however the conn_map will vary)

+		   

+		node_on_switch_state = function(pos, node, oldstate, newstate)

+		^- Called when the node state is switched by advtrains, after the node replacement has commenced.

+		

+		Turnout switching can happen programmatically via advtrains.setstate(pos, state), via user right_click or via the interlocking system.

+		In no other situation is it permissible to exchange track nodes in-place, unless both at_conns and at_conn_map stay identical.

+		

+		Note that the fields node_state, node_next_state and node_state_map completely replace the getstate/setstate functions.

+		There must be a one-to-one mapping between states and node names and no function can be defined for state switching.

+		This principle enables the seamless working of the interlocking autorouter and reduces failure points.

+		The node_state_* system can also be used as drop-in replacement for the passive-API-enabled nodes (andrews-cross, mesecon_switch etc.)

+		The advtrains API functions advtrains.getstate() and advtrains.setstate() remain the programmatic access points, but will now utilize the new state system.

+		

+		

+		trackworker_next_rot = <nodename of next rotation step>,

+		^- if set, right-click with trackworker will set this node

+		trackworker_rot_incr_param2 = true

+		^- if set, trackworker will increase node param2 on rightclick

+		

+		trackworker_next_var = <nodename of next variant>

+		^- if set, left-click with trackworker will set this node

+	}

+	})

+

+]]--

+

+-- This file provides some utilities to register tracks, but tries to not get into the way too much

+

+

+function advtrains.track_can_dig_callback(pos, player)

+	local ok, reason = advtrains.can_dig_or_modify_track(pos)

+	if not ok and player then

+		minetest.chat_send_player(player:get_player_name(), attrans("This track can not be removed!") .. " " .. reason)

+	end

+	return ok

+end

+

+function advtrains.track_update_callback(pos)

+	advtrains.ndb.update(pos)

+end

+

+function advtrains.state_node_on_rightclick_callback(pos, node, player)

+	if advtrains.check_turnout_signal_protection(pos, player:get_player_name()) then

+		local ndef = minetest.registered_nodes[node.name]

+		if ndef and ndef.advtrains and ndef.advtrains.node_next_state then

+			advtrains.setstate(pos, ndef.advtrains.node_next_state, node)

+			advtrains.log("Switch", player:get_player_name(), pos)

+		end

+	end

+end

+

+-- advtrains.register_node_4rot(name, nodedef)

+-- Registers four rotations for the node defined by nodedef (0°, 30°, 45° and 60°; the 4 90°-steps are already handled by the param2, resulting in 16 directions total).

+-- You must provide the definition for the base node, and certain fields are altered automatically for the 3 additional rotations:

+--  name: appends the suffix "_30", "_45" or "_60"

+--  description: appends the rotation (human-readable) in parenthesis

+--  tiles_prefix: if defined, "tiles" field will be set as prefix..rotationExtension..".png"

+--  mesh_prefix, mesh_suffix: if defined, "mesh" field will be set as prefix..rotationExtension..suffix

+--  at_conns: are rotated according to the node rotation

+--  node_state_map, trackworker_next_var: appends the suffix appropriately.

+--  groups: applies save_in_at_nodedb and not_blocking_trains groups if not already present

+-- The nodes are registered in the trackworker to be rotated with right-click.

+-- definition_mangling_function is an optional parameter. For each of the 4 rotations, it gets passed the modified node definition and may perform final modifications to it.

+--  signature: function definition_mangling_function(name, nodedef, rotationIndex, rotationSuffix)

+--  Example usage: define the setstate function of turnouts (if that is not done via the "automatic" way of state_node_map)

+local rotations = {

+	{i = 0, s = "",    h = " (0)",  n = "_30"},

+	{i = 1, s = "_30", h = " (30)", n = "_45"},

+	{i = 2, s = "_45", h = " (45)", n = "_60"},

+	{i = 3, s = "_60", h = " (60)", n = ""},

+}

+function advtrains.register_node_4rot(ori_name, ori_ndef, definition_mangling_function)

+	for _, rot in ipairs(rotations) do

+		local ndef = table.copy(ori_ndef)

+		if ori_ndef.advtrains then

+			-- make sure advtrains table is deep-copied because we may need to replace node_state_map

+			ndef.advtrains = table.copy(ori_ndef.advtrains)

+		else

+			ndef.advtrains = {} -- we need the table later for trackworker

+		end

+		-- Perform the name mangling

+		local suffix = rot.s

+		local name = ori_name..suffix

+		ndef.description = ori_ndef.description .. rot.h

+		if ori_ndef.tiles_prefix then

+			ndef.tiles = { ori_ndef.tiles_prefix .. suffix .. ".png" }

+		end

+		if ori_ndef.mesh_prefix then

+			ndef.mesh = ori_ndef.mesh_prefix .. suffix .. ori_ndef.mesh_suffix

+		end

+		-- rotate connections

+		if ori_ndef.at_conns then

+			ndef.at_conns = advtrains.rotate_conn_by(ori_ndef.at_conns, rot.i)

+		end

+		-- update node state map if present

+		if ori_ndef.advtrains then

+			if ori_ndef.advtrains.node_state_map then

+				local new_nsm = {}

+				for state, nname in pairs(ori_ndef.advtrains.node_state_map) do

+					new_nsm[state] = nname .. suffix

+				end

+				ndef.advtrains.node_state_map = new_nsm

+			end

+			if ori_ndef.advtrains.trackworker_next_var then

+				ndef.advtrains.trackworker_next_var = ori_ndef.advtrains.trackworker_next_var .. suffix

+			end

+			-- apply trackworker rot field

+			ndef.advtrains.trackworker_next_rot = ori_name .. rot.n

+			ndef.advtrains.trackworker_rot_incr_param2 = (rot.n=="")

+		end

+		-- apply groups

+		ndef.groups.save_in_at_nodedb = 1

+		ndef.groups.not_blocking_trains = 1

+		

+		-- give the definition mangling function an option to do some adjustments

+		if definition_mangling_function then

+			definition_mangling_function(name, ndef, rot.i, suffix)

+		end

+		

+		-- register node

+		minetest.register_node(":"..name, ndef)

+		

+		-- if this has the track_place_group set, register as a candidate for the track_place_group

+		if ndef.advtrains.track_place_group then

+			advtrains.trackplacer.register_candidate(ndef.advtrains.track_place_group, name, ndef, ndef.advtrains.track_place_single, true)

+		end

+	end

+end

+

+-- track-related helper functions

+

+function advtrains.is_track(nodename)

+	if not minetest.registered_nodes[nodename] then

+		return false

+	end

+	local nodedef=minetest.registered_nodes[nodename]

+	if nodedef and nodedef.groups.advtrains_track then

+		return true

+	end

+	return false

+end

+

+-- returns the connection tables of the track with given node details

+-- returns: conns table, railheight, conn_map table

+function advtrains.get_track_connections(name, param2)

+	local nodedef=minetest.registered_nodes[name]

+	if not nodedef then atprint(" get_track_connections couldn't find nodedef for nodename "..(name or "nil")) return nil end

+	local noderot=param2

+	if not param2 then noderot=0 end

+	if noderot > 3 then atprint(" get_track_connections: rail has invaild param2 of "..noderot) noderot=0 end

+	

+	if not nodedef.at_conns then

+		return nil

+	end

+	--atdebug("Track connections of ",name,param2,":",nodedef.at_conns)

+	return advtrains.rotate_conn_by(nodedef.at_conns, noderot*AT_CMAX/4), (nodedef.at_rail_y or 0), nodedef.at_conn_map

+end

+

+-- Function called when a track is about to be dug or modified by the trackworker

+-- Returns either true (ok) or false,"translated string describing reason why it isn't allowed"

+-- Impl Note: possibly duplicate code in "self contained TCB" - see interlocking/tcb_ts_ui.lua!

+function advtrains.can_dig_or_modify_track(pos)

+	if advtrains.get_train_at_pos(pos) then

+		return false, attrans("Position is occupied by a train.")

+	end

+	-- interlocking: tcb, signal IP a.s.o.

+	if advtrains.interlocking then

+		-- TCB?

+		if advtrains.interlocking.db.get_tcb(pos) then

+			return false, attrans("There's a Track Circuit Break here.")

+		end

+		-- signal ip?

+		if advtrains.interlocking.db.is_ip_at(pos, true) then -- is_ip_at with purge parameter

+			return false, attrans("There's a Signal Influence Point here.")

+		end

+	end

+	return true

+end