JIT-compile ATC commands

4 files changed, 373 insertions, 189 deletions

diff --git a/advtrains/atc.lua b/advtrains/atc.lua
index 64cdcec..9f909c5 100644
--- a/advtrains/atc.lua
+++ b/advtrains/atc.lua
@@ -53,15 +53,7 @@ function atc.send_command(pos, par_tid)
 					atwarn("ATC rail at", pos, ": Rail not on train's path! Can't determine arrow direction. Assuming +!")
 				end
 				
-				local command = atc.controllers[pts].command				
-				command = eval_conditional(command, iconnid==1, train.velocity)
-				if not command then command="" end
-				command=string.match(command, "^%s*(.*)$")
-				
-				if command == "" then
-					atprint("Sending ATC Command to", train_id, ": Not modifying, conditional evaluated empty.")
-					return true
-				end
+				local command = atc.controllers[pts].command
 				
 				atc.train_set_command(train, command, iconnid==1)
 				atprint("Sending ATC Command to", train_id, ":", command, "iconnid=",iconnid)
@@ -188,189 +180,17 @@ function atc.get_atc_controller_formspec(pos, meta)
 	return formspec.."button_exit[0.5,4.5;7,1;save;"..attrans("Save").."]"
 end
 
---from trainlogic.lua train step
-local matchptn={
-	["SM"]=function(id, train)
-		train.tarvelocity=train.max_speed
-		return 2
-	end,
-	["S([0-9]+)"]=function(id, train, match)
-		train.tarvelocity=tonumber(match)
-		return #match+1
-	end,
-	["B([0-9]+)"]=function(id, train, match)
-		if train.velocity>tonumber(match) then
-			train.atc_brake_target=tonumber(match)
-			if not train.tarvelocity or train.tarvelocity>train.atc_brake_target then
-				train.tarvelocity=train.atc_brake_target
-			end
-		end
-		return #match+1
-	end,
-	["BB"]=function(id, train)
-		train.atc_brake_target = -1
-		train.tarvelocity = 0
-		return 2
-	end,
-	["W"]=function(id, train)
-		train.atc_wait_finish=true
-		return 1
-	end,
-	["D([0-9]+)"]=function(id, train, match)
-		train.atc_delay=tonumber(match)
-		return #match+1
-	end,
-	["R"]=function(id, train)
-		if train.velocity<=0 then
-			advtrains.invert_train(id)
-			advtrains.train_ensure_init(id, train)
-			-- no one minds if this failed... this shouldn't even be called without train being initialized...
-		else
-			atwarn(sid(id), attrans("ATC Reverse command warning: didn't reverse train, train moving!"))
-		end
-		return 1
-	end,
-	["O([LRC])"]=function(id, train, match)
-		local tt={L=-1, R=1, C=0}
-		local arr=train.atc_arrow and 1 or -1
-		train.door_open = tt[match]*arr
-		return 2
-	end,
-	["K"] = function(id, train)
-		if train.door_open == 0 then
-			atwarn(sid(id), attrans("ATC Kick command warning: Doors closed"))
-			return 1
-		end
-		if train.velocity > 0 then
-			atwarn(sid(id), attrans("ATC Kick command warning: Train moving"))
-			return 1
-		end
-		local tp = train.trainparts
-		for i=1,#tp do
-			local data = advtrains.wagons[tp[i]]
-			local obj = advtrains.wagon_objects[tp[i]]
-			if data and obj then
-				local ent = obj:get_luaentity()
-				if ent then
-					for seatno,seat in pairs(ent.seats) do
-						if data.seatp[seatno] and not ent:is_driver_stand(seat) then
-							ent:get_off(seatno)
-						end
-					end
-				end
-			end
-		end
-		return 1
-	end,
-	["A([01])"]=function(id, train, match)
-		if not advtrains.interlocking then return 2 end
-		advtrains.interlocking.ars_set_disable(train, match=="0")
-		return 2
-	end,
-}
-
-eval_conditional = function(command, arrow, speed)
-	--conditional statement?
-	local is_cond, cond_applies, compare
-	local cond, rest=string.match(command, "^I([%+%-])(.+)$")
-	if cond then
-		is_cond=true
-		if cond=="+" then
-			cond_applies=arrow
-		end
-		if cond=="-" then
-			cond_applies=not arrow
-		end
-	else 
-		cond, compare, rest=string.match(command, "^I([<>]=?)([0-9]+)(.+)$")
-		if cond and compare then
-			is_cond=true
-			if cond=="<" then
-				cond_applies=speed<tonumber(compare)
-			end
-			if cond==">" then
-				cond_applies=speed>tonumber(compare)
-			end
-			if cond=="<=" then
-				cond_applies=speed<=tonumber(compare)
-			end
-			if cond==">=" then
-				cond_applies=speed>=tonumber(compare)
-			end
-		end
-	end	
-	if is_cond then
-		atprint("Evaluating if statement: "..command)
-		atprint("Cond: "..(cond or "nil"))
-		atprint("Applies: "..(cond_applies and "true" or "false"))
-		atprint("Rest: "..rest)
-		--find end of conditional statement
-		local nest, pos, elsepos=0, 1
-		while nest>=0 do
-			if pos>#rest then
-				atwarn(sid(id), attrans("ATC command syntax error: I statement not closed: @1",command))
-				return ""
-			end
-			local char=string.sub(rest, pos, pos)
-			if char=="I" then
-				nest=nest+1
-			end
-			if char==";" then
-				nest=nest-1
-			end
-			if nest==0 and char=="E" then
-				elsepos=pos+0
-			end
-			pos=pos+1
-		end
-		if not elsepos then elsepos=pos-1 end
-		if cond_applies then
-			command=string.sub(rest, 1, elsepos-1)..string.sub(rest, pos)
-		else
-			command=string.sub(rest, elsepos+1, pos-2)..string.sub(rest, pos)
-		end
-		atprint("Result: "..command)
-	end
-	return command
-end
-
 function atc.execute_atc_command(id, train)
-	--strip whitespaces
-	local command=string.match(train.atc_command, "^%s*(.*)$")
-	
-	
-	if string.match(command, "^%s*$") then
-		train.atc_command=nil
-		return
-	end
-
-	train.atc_command = eval_conditional(command, train.atc_arrow, train.velocity)
-	
-	if not train.atc_command then return end
-	command=string.match(train.atc_command, "^%s*(.*)$")
-	
-	if string.match(command, "^%s*$") then
-		train.atc_command=nil
-		return
-	end
-	
-	for pattern, func in pairs(matchptn) do
-		local match=string.match(command, "^"..pattern)
-		if match then
-			local patlen=func(id, train, match)
-			
-			atprint("Executing: "..string.sub(command, 1, patlen))
-			
-			train.atc_command=string.sub(command, patlen+1)
-			if train.atc_delay<=0 and not train.atc_wait_finish then
-				--continue (recursive, cmds shouldn't get too long, and it's a end-recursion.)
-				atc.execute_atc_command(id, train)
-			end
-			return
+	local w, e = advtrains.atcjit.execute(id, train)
+	if w then
+		for i = 1, #w, 1 do
+			atwarn(sid(id),w[i])
 		end
 	end
-	atwarn(sid(id), attrans("ATC command parse error: Unknown command: @1", command))
-	atc.train_reset_command(train, true)
+	if e then
+		atwarn(sid(id),e)
+		atc.train_reset_command(train, true)
+	end
 end
 
 
diff --git a/advtrains/atcjit.lua b/advtrains/atcjit.lua
new file mode 100644
index 0000000..0d400ea
--- /dev/null
+++ b/advtrains/atcjit.lua
@@ -0,0 +1,206 @@
+local aj_cache = {}
+
+local aj_tostring
+
+local matchptn = {
+	["A[01FT]"] = function(match)
+		return string.format(
+			"advtrains.interlocking.set_ars_disable(train,%s)",
+			(match=="0" or match=="F") and "true" or "false"), false
+	end,
+	["BB"] = function()
+		return [[do
+			train.atc_brake_target = -1
+			train.tarvelocity = 0
+		end]], 2
+	end,
+	["B([0-9]+)"] = function(match)
+		return string.format([[do
+			train.atc_brake_target = %s
+			if not train.tarvelocity or train.tarvelocity > train.atc_brake_target then
+				train.tarvelocity = train.atc_brake_target
+			end
+		end]], match),#match+1
+	end,
+	["D([0-9]+)"] = function(match)
+		return string.format("train.atc_delay = %s", match), #match+1, true
+	end,
+	["(%bI;)"] = function(match)
+		local i = 2
+		local l = #match
+		local epos
+		while (i<l) do
+			local b, e, c = string.find(match,"([IE])",i)
+			if c == "I" then
+				b, e = string.find(match,"%bI;", b)
+				-- This is unlikely to happen since the %b pattern is balanced
+				if not (b and e) then return nil, "Malformed nested I statement" end
+				i = e+1
+			else
+				epos = b
+				break
+			end
+		end
+		local endp = string.find(match,"[WDI]") and true
+		local cond = string.match(match,"^I([+-])")
+		if cond then
+			local vtrue = string.sub(match, 3, epos and epos-1 or -2)
+			local vfalse = epos and string.sub(match, epos+1, -2)
+			local cstr = (cond == "-") and "not" or ""
+			local tstr, err = aj_tostring(vtrue, 1, true)
+			if not tstr then return nil, err end
+			if vfalse then
+				local fstr, err = aj_tostring(vfalse, 1, true)
+				if not fstr then return nil, err end
+				return string.format("if %s train.atc_arrow then %s else %s end",
+					cstr, tstr, fstr), l, endp
+			else
+				return string.format("if %s train.atc_arrow then %s end", cstr, tstr), l, endp
+			end
+		else
+			local op, ref = string.match(match,"^I([<>]=?)([0-9]+)")
+			if not op then
+				return _, "Invalid I statement"
+			end
+			local spos = 2+#op+#ref
+			local vtrue = string.sub(match, spos, epos and epos-1 or -2)
+			local vfalse = epos and string.sub(match, epos+1, -2)
+			local cstr = string.format("train.velocity %s %s", op, ref)
+			local tstr = aj_tostring(vtrue, 1, true)
+			if vfalse then
+				local fstr, err = aj_tostring(vfalse, 1, true)
+				if not fstr then return nil, err end
+				return string.format("if %s then %s else %s end", cstr, tstr, fstr), l, endp
+			else
+				return string.format("if %s then %s end", cstr, tstr), l, endp
+			end
+		end
+	end,
+	["K"] = function()
+		return [=[do
+			if train.door_open == 0 then
+				_w[#_w+1] = attrans("ATC Kick command warning: Doors are closed")
+			elseif train.velocity>0 then
+				_w[#_w+1] = attrans("ATC Kick command warning: Train moving")
+			else
+				local tp = train.trainparts
+				for i = 1, #tp do
+					local data = advtrains.wagons[tp[i]]
+					local obj = advtrains.wagon_objects[tp[i]]
+					if data and obj then
+						local ent = obj:get_luaentity()
+						if ent then
+							for seatno, seat in pairs(ent.seats) do
+								if data.seatp[seatno] and not ent:is_driver_stand(seat) then
+									ent:get_off(seatno)
+								end
+							end
+						end
+					end
+				end
+			end
+		end]=], 1
+	end,
+	["O([LR])"] = function(match)
+		local tt = {L = -1, R = 1}
+		return string.format("train.door_open = %d*(train.atc_arrow and 1 or -1)",tt[match]), 2
+	end,
+	["OC"] = function(match)
+		return "train.door_open = 0", 2
+	end,
+	["R"] = function()
+		return [[
+			if train.velocity<=0 then
+				advtrains.invert_train(id)
+				advtrains.train_ensure_init(id, train)
+			else
+				_w[#_w+1] = attrans("ATC Reverse command warning: didn't reverse train, train moving!")
+			end]], 1
+	end,
+	["SM"] = function()
+		return "train.tarvelocity=train.max_speed", 2
+	end,
+	["S([0-9]+)"] = function(match)
+		return string.format("train.tarvelocity=%s",match), #match+1
+	end,
+	["W"] = function()
+		return "train.atc_wait_finish=true", 1, true
+	end,
+}
+
+local function aj_tostring_single(cmd, pos)
+	if not pos then pos = 1 end
+	for pattern, func in pairs(matchptn) do
+		local match = {string.match(cmd, "^"..pattern, pos)}
+		if match[1] then
+			return func(unpack(match))
+		end
+	end
+	return nil
+end
+
+aj_tostring = function(cmd, pos, noreset)
+	if not pos then pos = 1 end
+	local t = {}
+	local endp = false
+	while pos <= #cmd do
+		if string.match(cmd,"^%s+$", pos) then break end
+		local _, e = string.find(cmd, "^%s+", pos)
+		if e then pos = e+1 end
+		local str, len
+		str, len, endp = aj_tostring_single(cmd, pos)
+		if not str then
+			return nil, (len or "Invalid command or malformed I statement: "..string.sub(cmd,pos))
+		end
+		t[#t+1] = str
+		pos = pos+len
+		if endp then
+			if endp then
+				t[#t+1] = string.format("_c[#_c+1]=%q",string.sub(cmd, pos))
+			end
+			break
+		end
+	end
+	return table.concat(t,"\n"), pos
+end
+
+local function aj_compile(cmd)
+	if aj_cache[cmd] then
+		local x = aj_cache[cmd]
+		if type(x) == "function" then
+			return x
+		else
+			return nil, x
+		end
+	end
+	local str, err = aj_tostring(cmd)
+	if not str then
+		aj_cache[cmd] = err
+		return nil, err
+	end
+	local str = string.format([[return function(id,train)
+		local _c = {}
+		local _w = {}
+		%s
+		if _c[1] then train.atc_command=table.concat(_c)
+		else train.atc_command = nil end
+		return _w, nil
+	end]], str)
+	local f, e = loadstring(str)
+	if not f then return nil, e end
+	f = f()
+	aj_cache[cmd] = f
+	return f
+end
+
+local function aj_execute(id,train)
+	if not train.atc_command then return end
+	local func, err = aj_compile(train.atc_command)
+	if func then return func(id,train) end
+	return nil, err
+end
+
+return {
+	compile = aj_compile,
+	execute = aj_execute
+}
diff --git a/advtrains/init.lua b/advtrains/init.lua
index 083281e..927d9e8 100644
--- a/advtrains/init.lua
+++ b/advtrains/init.lua
@@ -198,6 +198,8 @@ advtrains.meseconrules =
 
 advtrains.fpath=minetest.get_worldpath().."/advtrains"
 
+advtrains.atcjit=dofile(advtrains.modpath.."/atcjit.lua")
+
 dofile(advtrains.modpath.."/path.lua")
 dofile(advtrains.modpath.."/trainlogic.lua")
 dofile(advtrains.modpath.."/trainhud.lua")
diff --git a/advtrains/tests/atcjit_spec.lua b/advtrains/tests/atcjit_spec.lua
new file mode 100644
index 0000000..8e2a8b7
--- /dev/null
+++ b/advtrains/tests/atcjit_spec.lua
@@ -0,0 +1,156 @@
+package.path  =  "../?.lua;" .. package.path
+advtrains = {}
+_G.advtrains = advtrains
+function _G.attrans(...) return ... end
+function advtrains.invert_train() end
+function advtrains.train_ensure_init() end
+
+local atcjit = require("atcjit")
+
+local function assert_atc(train, warn, err, res)
+	local w, e = atcjit.execute(train.id,train)
+	assert.same(err, e)
+	if w then assert.same(warn, w) end
+	assert.same(res, train)
+end
+
+local function thisatc(desc, train, warn, err, res)
+	it(desc, function() assert_atc(train, warn, err, res) end)
+end
+
+describe("simple ATC track", function()
+	local t = {
+		atc_arrow = true,
+		atc_command = " B12WB8WBBWOLD15ORD15OCD1RS10WSM",
+		door_open = 0,
+		max_speed = 20,
+		tarvelocity = 10,
+		velocity = 0,
+	}
+	thisatc("should make the train slow down to 12", t, {}, nil,{
+		atc_arrow = true,
+		atc_brake_target = 12,
+		atc_command = "B8WBBWOLD15ORD15OCD1RS10WSM",
+		atc_wait_finish = true,
+		door_open = 0,
+		max_speed = 20,
+		tarvelocity = 10,
+		velocity = 0,
+	})
+	thisatc("should make the train brake to 8", t, {}, nil, {
+		atc_arrow = true,
+		atc_brake_target = 8,
+		atc_command  = "BBWOLD15ORD15OCD1RS10WSM",
+		atc_wait_finish = true,
+		door_open = 0,
+		max_speed = 20,
+		tarvelocity = 8,
+		velocity = 0,
+	})
+	thisatc("should make the train stop", t, {}, nil, {
+		atc_arrow = true,
+		atc_brake_target = -1,
+		atc_command = "OLD15ORD15OCD1RS10WSM",
+		atc_wait_finish = true,
+		door_open = 0,
+		max_speed = 20,
+		tarvelocity = 0,
+		velocity = 0,
+	})
+	thisatc("should make the train open its left doors", t, {}, nil, {
+		atc_arrow = true,
+		atc_brake_target = -1,
+		atc_command = "ORD15OCD1RS10WSM",
+		atc_delay = 15,
+		atc_wait_finish = true,
+		door_open = -1,
+		max_speed = 20,
+		tarvelocity = 0,
+		velocity = 0,
+	})
+	thisatc("should make the train open its right doors", t, {}, nil,{
+		atc_arrow = true,
+		atc_brake_target = -1,
+		atc_command = "OCD1RS10WSM",
+		atc_delay = 15,
+		atc_wait_finish = true,
+		door_open = 1,
+		max_speed = 20,
+		tarvelocity = 0,
+		velocity = 0,
+	})
+	thisatc("should make the train close its doors", t, {}, nil, {
+		atc_arrow = true,
+		atc_brake_target = -1,
+		atc_command = "RS10WSM",
+		atc_delay = 1,
+		atc_wait_finish = true,
+		door_open = 0,
+		max_speed = 20,
+		tarvelocity = 0,
+		velocity = 0,
+	})
+	thisatc("should make the train depart and accelerate to 10", t, {}, nil, {
+		atc_arrow = true,
+		atc_brake_target = -1,
+		atc_command = "SM",
+		atc_delay = 1,
+		atc_wait_finish = true,
+		door_open = 0,
+		max_speed = 20,
+		tarvelocity = 10,
+		velocity = 0,
+	})
+	thisatc("should make the train accelerate to 20", t, {}, nil, {
+		atc_arrow = true,
+		atc_brake_target = -1,
+		atc_delay = 1,
+		atc_wait_finish = true,
+		door_open = 0,
+		max_speed = 20,
+		tarvelocity = 20,
+		velocity = 0,
+	})
+end)
+
+describe("ATC track with whitespaces", function()
+	local t = {
+		atc_command = " \t\n OC \n S20 \r "
+	}
+	thisatc("should not cause errors", t, {}, nil, {
+		door_open = 0,
+		tarvelocity = 20,
+	})
+end)
+
+describe("empty ATC track", function()
+	local t = {atc_command = ""}
+	thisatc("should not do anything", t, {}, nil, {})
+end)
+
+describe("ATC track with nested I statements", function()
+	local t = {
+		atc_arrow = false,
+		atc_command = "I+OREI>5I<=10S16WORES12;D15;;OC",
+		velocity = 10,
+		door_open = 0,
+	}
+	thisatc("should make the train accelerate to 16", t, {}, nil,{
+		atc_arrow = false,
+		atc_command = "ORD15OC",
+		atc_wait_finish = true,
+		velocity = 10,
+		door_open = 0,
+		tarvelocity = 16,
+	})
+end)
+
+describe("ATC track with invalid statement", function()
+	local t = { atc_command = "Ifoo" }
+	thisatc("should report an error", t, {}, "Invalid command or malformed I statement: Ifoo", t)
+end)
+
+describe("ATC track with invalid I condition", function()
+	local t = { atc_command = "I?;" }
+	thisatc("should report an error", t, {}, "Invalid I statement", t)
+end)