-- nef version 2 20211221
function _freeciv_state_dump()

local script = "" -- toggle comment on next line for lang. support in Npp etc..
 .. [[ 
local sc = {n=0;ul="unit_lost"}
for s, n in function(sc)return find.signal_callback (sc.ul,0), sc.n +1 end, sc, nil
do sc[n] = s; sc.n = n; signal.remove (sc.ul,s ) end
local f = (function()
  for p in players_iterate () do
    for i, itr in ipairs {p.cities_iterate, p.units_iterate} do
      for uc in itr(p) do
        if uc.tile then local id, T = 0
          repeat T = find.unit_type (id); id = id +1
            if T and T:can_exist_at_tile(uc.tile)
            then return {p = p, t = uc.tile, T = T}
            end
          until not T
        end
      end
    end
  end
end) ()
local ne = setmetatable ( {find.nonexistent ()}, 
 {__index = function (t, a)  -- upvalue: f
  local unit = 
    assert( f and edit.create_unit (f.p, f.t, f.T, 0, nil, -1),
                      "No suitable player to restore Nonexistent")
  edit.unit_kill (unit, "used", f.p); t[a] = unit; return t[a] end} )
  
local index = function (t, a) t[a] = {}; return t[a] end;     
local t = setmetatable ( {_ENV}, {
   __call  = function (t, im, ...)    local m = t[im]
              for i, a in ipairs ({...}) do m = setmetatable (t[a],m) end 
              return m
             end;
   __index = index;
                                 } )
for n, s in ipairs(sc) do signal.connect(sc.ul,s) end
local sc = setmetatable({},{__index = index;} )  -- ]] 
  .."\n"
 -- *******end of the vars script prologue*********
  local TT -- forward
  local ri = {_ENV}
  local t1 = setmetatable (  { [ri[1]] = 1; n = 1;
 rollback = function (t1)
              t1.t2 = {}; getmetatable(t1).__index = t1.t2; 
              t1.r = t1.n
            end;
 commit   = function (t1, ri)                           
              for tbl, inx in pairs (t1.t2) do t1[tbl] = inx; ri[inx] = tbl end; 
              t1.n = t1.r
            end;
 newset   = function (t1, da)
              if not t1[da] then t1.r = t1.r +1; t1.t2[da] = t1.r end return t1[da]
            end;
 getmeta  = function (da) 
              da = getmetatable(da); return type (da) == "table" and da
            end;                
                       } , {            
     __call   =  function (t1, da) local d, x = da, {}
         repeat d = t1.getmeta(d)
           if d then d = rawget(d, "_fc_keep") else return {} end 
           local T = type(d); if T ~= "table" 
           then if (TT [T](d)).text then break else return {} end
           else if x[d]             then break else x[d]=true end
           end 
         until false

         local s, dx = {}
         while da do   -- beware side effect in newset
            dx = not t1[da] and t1.getmeta (da)
            table.insert (s, 1, t1:newset(da)); da = dx
         end; return {text = "t("..table.concat(s, ", ")..")"} 
                  
                 end;  -- __call
                           }  )

  local function get_text(da) 
    if not da:find ("[%c\x80-\xFF]") then return ("%q"):format(da) end -- else
    local s= {}; for i = 1, #da do s[i] = da:byte (i) end
    return "string.char("..table.concat(s, ", ")..")"
  end
                  
  local NE = setmetatable ( {[find.nonexistent ()] = 1;n=1},
   {__index = function (t, a) t.n = t.n + 1; t[a] = t.n; return t.n end;} )
  local p2      = {Unit = "nil, "; City = "nil, ";}
  local n_list ={direction = true;}
  local no_text = function (da) return {} end
  local text_ok = function (da) return {text= ("%q"):format(da)} end
        TT      = setmetatable ( {                       -- table first
    boolean      = text_ok;
    number       = text_ok;
    -- number       = function (da) return {text= ("%s"):format(da)} end;
    -- number       = function (da) return {text= da} end;
    thread       = no_text;
    ["function"] = no_text;
    ["nil"]      = no_text;
    table        = t1;         -- see __call in t1 metatable
    userdata     = function (da)      -- upvalues:  p2, NE, n_list         
        local  Type = tolua.type (da); local l_ud = Type:lower()
        local  rule, name, id = da.rule_name, da.name, da.id return            { 
           text = Type == "Nonexistent" and "ne["..NE[da].."]"  or
                  find [l_ud] and (rule or name or id) and "find."..l_ud.."("..
                  ( rule and ("%q"):format(da:rule_name())          or
                  ( name and n_list [l_ud] and ("%q"):format(name)) or
                  --[[id and]] (p2[Type] or "")..(math.floor(id)) )..")"       }
                   end;
    string       = function (da)
                    return { text = get_text(da), us  = da:find ("^_[%w_]*$")  }
                   end;     
                            }, {                      -- now metatable
       __call = function (tt, da) return tt [type(da)] (da) end;
                               }  ) -- TT []
  
  
  for inx, tbl in ipairs (ri) do
     for ca, cd in next, tbl, nil do t1:rollback()
       local a, d = TT (ca), TT (cd)
       if    a.text and (inx > 1 or not a.us) and d.text 
       then  t1:commit (ri); script = script.. 
         "rawset(t["..inx.."], "..a.text..", "..d.text.."); \n" 
       end
     end     -- in next
  end       -- in ipairs
  
  for s_id, ss in (function (s, s_id) s_id = s_id + 1
        local ss = find.signal (s_id) return ss and s_id, ss 
				   end), nil, -1 do
    for c_id, cf in (function (ss, c_id) c_id = c_id + 1
          local cf = find.signal_callback (ss, c_id) return cf and c_id, cf 
                     end), ss, -1 do
      script = script..(("sc[%s][%s] = "..get_text(cf).."; \n"):format(s_id, c_id)) 
    end;  -- for c_id, cf
  end  -- for s_id, ss 
  
  return script.."if type(_fc_restore)=='function' then _fc_restore(t,ne,sc) end\n"
  
end