No idea.

init.lua

@@ -1,7 +1,61 @@
+local statedir = minetest.get_worldpath() .. '/' .. minetest.get_current_modname() .. "/"
+local oldprint=print
+local function print(...)
+ for k,v in ipairs({...}) do
+  oldprint("[Test3D] "..tostring(v))
+ end
+end
+print("Test3D loading.")
+print("State directory: "..statedir)
+if not digiline then
+ print("Digilines not found.")
+ return
+ end
 local function t21_digiline_receive(pos, node, channel, msg)
  print(pos,node,channel,msg)
 end
+print("Created T21 digiline function")
 
+print("Loading/creating states")
+_G.test3d = {}
+_G.test3d.states={}
+-- states:
+--[[
+{
+mem = {4096 ints}
+nodes = int
+pc = int
+}
+]]--
+function _G.test3d.save()
+ local f = io.open(statedir.."/states.txt","wb")
+ for k,v in pairs(test3d.states) do
+  f:write(tostring(k).."\n")
+  local g=io.open(statedir.."/"..tostring(k))
+  for l,m in ipairs(test3d.states[k]) do
+   g:write(tostring(m).."\n")
+  end
+  g:close()
+ end
+ f:close()
+end
+_G.test3d.laststate=0
+_G.test3d.genstate = {}
+local statetab={}
+os.execute("mkdir "..statedir) -- just in case, 50/50 this kills minetest on some platforms
+local f=io.open(statedir.."/states.txt","rb")
+local statetab={}
+if f ~= nil then
+ f:close()
+ for l in io.lines(statedir.."/states.txt") do
+  print("State: "..l)
+ end
+end
+print("Creating T21 formspec")
+local function t21_set_meta(pos)
+ minetest.get_meta(pos):set_string("formspec", "field[channel;Channel;${channel}]\nfield[statename;State;${statename}]")
+end
+minetest.register_on_shutdown(test3d.save)
 minetest.register_node("test3d:t21", {
  description = "T21 Execution Node",
  tiles = {
@@ -16,6 +70,7 @@ minetest.register_node("test3d:t21", {
    },
   },
  },
+ on_construct = t21_set_meta,
  on_punch = function(pos, _, _, _)
   local meta=minetest.get_meta(pos)
   local cbeep = meta:get_int("test3d_running")
@@ -34,8 +89,17 @@ minetest.register_node("test3d:t21", {
   effector = {
    action = t21_digiline_receive
   }
- }
+ },
+ on_receive_fields = function(pos,_,fields,sender)
+  local meta = minetest.get_meta(pos)
+  _G.test3d.states[meta:get_string("statename")].nodes=_G.test3d.states[meta:get_string("statename")].nodes-1 -- decrement node counter
+  meta:set_string("statename",fields.statename)
+  meta:set_string("channel",fields.channel) -- channel the thing listens for commands on
+  _G.test3d.states[meta:get_string("statename")].nodes=_G.test3d.states[meta:get_string("statename")].nodes+1 -- increment new node counter
+ end
 })
+print("T21 node registered")
+
 minetest.register_abm({
  nodenames={"test3d:t21"},
  interval=1,
@@ -46,12 +110,25 @@ minetest.register_abm({
   local beepState = meta:get_int("test3d_running")
   if beepState == nil then beepState=1 end
 --  print(beepState)
-  if beepState == 1 then
-   minetest.sound_play("default_break_glass",{
+  if beepState == 1 and meta:get_string("statename") ~= nil and meta:get_string("statename") ~= "" then
+--[[   minetest.sound_play("default_break_glass",{
     pos=pos,
     max_hear_distance=100
    })
+]]--
+   print("Running T21 node with instance "..tostring(meta:get_string("statename")).." at position "..tostring(pos.x)..","..tostring(pos.y)..","..tostring(pos.z))
   end
  end,
 })
-print("Test3D loaded.")
+print("T21 ABMs registered")
+
+minetest.register_chatcommand("lua", { -- I'm a terrible person
+ params = "<text>",
+ description = "Execute some Lua code",
+ privs = {talk = true},
+ func = function( _ , text)
+  e,lstr = pcall(loadstring(text))
+  minetest.chat_send_all(tostring(lstr))
+ end,
+})
+