startup:263: attempt to concatenate nil and string

Hello,

I have a problem with computercraft.

i built a nuclear power plant station it will be controlled by computer.
i start the computer registering the reactors to Ar_reactors while registering the reactors the error startup:263: attempt to concatenate nil and string is coming

Here the whole code:

function everything()
print('Waiting for possible chunk loading...')
sleep(2) --wait for chunk loading

--------configurations
--sensors--
AR_Sensor_Prefix=''
side=sensors.getController()
--actuators--
BC_side='back'
BCbustransceiver_side='bottom'
ACcolors={c_power=colors.purple,c_ice=colors.blue,c_uran=colors.lime,c_retriever=colors.brown}
mon_side='top' --it is optional to have a monitor

--id tags--
ucell_name='item.itemCellUran'--replace 0 by number till
uneardepleted_name='item.itemCellUranEmpty'
ureenriched_name='item.itemCellUranEnriched'
ice_name='tile.ice'
--------configurations end
message={}
function update(arg)
term.clear()
if #arg>0 then message=arg end
for i, v in ipairs(message) do print(v) end
if power==true then s='On' else s='Off' end
print('Power '..s)
print('maxUran:'..tostring(maxUran)..'. To depletion:'..tostring((10000-maxUran-params.Umin)/params.Uspeed/60)..' mn.')
print('min_iceslots:'..tostring(min_iceslots))
print('ice_missing:'..tostring(ice_missing))
print('n_to_withdraw:'..tostring(n_to_withdraw))
print('n_slots_free:'..tostring(n_slots_free))
params=getSavedParams()
updateReactorsState()
for i,reactor in pairs(reactors) do
  if not compress(reactor.ice_slots_start)==compress(reactor.ice_slots) then
	error('Ice slots changed in Reactor '..reactor.name..'. Pos:'..reactor.pos)
  end
end
end
function getReactors()
reactors={}
for i,sensor in ipairs(sensors.getSensors(side)) do
  if sensor:sub(0,#AR_Sensor_Prefix)==AR_Sensor_Prefix then
  if (not sensors.getAvailableReadings(side, sensor)[1]=='No Readings found') or sensors.getAvailableReadings(side, sensor)[1]=='TargetInfo' then
  if sensors.getSensorInfo(side, sensor).cardType=='IndustrialCraft2 SensorModule' then
   sensors.setSensorRange(side,sensor,'8')
   for j, target in ipairs(sensors.getAvailableTargetsforProbe(side,sensor,'ReactorContent')) do
	name='AR Reactor '..sensor:match('^'..AR_Sensor_Prefix..'(.*)')..' '..tostring(i)..':'..tostring(j)
	size=6*(3+tonumber(sensors.getSensorReadingAsDict(side,sensor,target,'Reactor').size))
	pos=target:match('(%d+,%d+,%d+)$')
	reactor={name=name, target=target, sensor=sensor, size=size, pos=pos}
	reactors[target]=reactor
   end
  end end end
end
new_reactors={}
for i,v in pairs(reactors) do new_reactors[#new_reactors+1]=v end
reactors=new_reactors
if #reactors==0 then print('No reactors found. Check adjacency of sensors, type of card and sensors name prefix:'..AR_Sensor_Prefix) end
return reactors
end


function UpdateReactorState(reactor)
local n_slots_filled=0
local ice_missing=0
local n_to_withdraw=0
local maxUran=0
local ice_slots={}
local min_iceslots=64

for i,v in pairs(sensors.getSensorReadingAsDict(side,reactor.sensor,reactor.target,'ReactorContent')) do
  n_slots_filled=n_slots_filled+1
  if v:sub(-2-#ice_name,-3)==ice_name then
   qty=tonumber(string.match(v,'^(%d*)%*'))
   ice_missing=ice_missing+64-qty
   ice_slots[#ice_slots+1]=i
   min_iceslots=math.min(min_iceslots,qty)
  elseif v:sub(-2-#uneardepleted_name,-3)==uneardepleted_name then
   n_to_withdraw=n_to_withdraw+tonumber(v:match('^(%d+)%*'))
  elseif v:sub(-2-#ureenriched_name,-3)==ureenriched_name then
   n_to_withdraw=n_to_withdraw+tonumber(v:match('^(%d+)%*'))
  elseif v:match(ucell_name..'@') then
   m=v:match('@(%d+)$')
   if m==nil then m=0 end
   maxUran=math.max(m,maxUran)
  end
end
table.sort(ice_slots)
reactor.ice_missing=ice_missing
reactor.n_to_withdraw=n_to_withdraw
reactor.n_slots_filled=n_slots_filled
reactor.maxUran=maxUran
reactor.ice_slots=ice_slots
reactor.min_iceslots=min_iceslots
end
function aggregateReactors(reactors)
if #reactors==0 then error('No reactors to aggregate.') end
t_size=0
for i, reactor in pairs(reactors) do
   UpdateReactorState(reactor)
   reactor.ice_slots_start=reactor.ice_slots
   t_size=t_size+reactor.size
end
print('Reactors aggregated. Total size:'..tostring(t_size))
end
function compress(a)
s=''
for i=1,#a do
  s=s..a[i]
end
return s
end
function updateReactorsState()
ice_missing=0
n_to_withdraw=0
n_slots_filled=0
maxUran=0
min_iceslots=64
n_t_ice_slots=0
for i,reactor in pairs(reactors) do
  UpdateReactorState(reactor)
  ice_missing=ice_missing+reactor.ice_missing
  n_to_withdraw=n_to_withdraw+reactor.n_to_withdraw
  n_slots_filled=n_slots_filled+reactor.n_slots_filled
  maxUran=math.max(reactor.maxUran,maxUran)
  min_iceslots=math.min(min_iceslots,reactor.min_iceslots)
  n_t_ice_slots=n_t_ice_slots+#reactor.ice_slots
end
n_slots_free=t_size-n_slots_filled
end

message={}

rs.setBundledOutput(BC_side,0)
BCnumbers={'1','2','4','8','16','32','64','128','256','512','1024','2048','4096','8192','16384','32768'}
BCstate={}
for i=1,#BCnumbers do
BCstate[BCnumbers[i]]=false
end
function setColor(c,Bool)
BCstate[tostring(c)]=Bool
BCnumber=0
for i=1,#BCnumbers do
  if BCstate[BCnumbers[i]]==true then
   BCnumber=BCnumber+tonumber(BCnumbers[i])
  end
end
rs.setBundledOutput(BC_side,BCnumber)
end
power=false
function Power(Bool)
	if not (power==Bool) then
	 power=Bool
  setColor(ACcolors.c_power,Bool)
  if Bool==true then s='On' else s='Off' end
  print('Power '..s)
end
end
function Ice(Bool)
setColor(ACcolors.c_ice,Bool)
end
function Retriever(Bool)
setColor(ACcolors.c_retriever,Bool)
end
function Uran(Bool)
setColor(ACcolors.c_uran,Bool)
end
--fill functions--
function fillUran()
update{}
if n_slots_free > 0 then
  update{'Inserting '..tostring(n_slots_free)..' Uranium cells.'}
  Uran(true)
  while n_slots_free>0 do sleep(params.main_delay) update{} end
  Uran(false)
end
end
function retrieve()
update{}
if n_to_withdraw>0 then
  update{'Retrieving '..tostring(n_to_withdraw)..' near depleted and/or re-enriched cells.'}
  Retriever(true)
  while n_to_withdraw>0 do sleep(params.main_delay) update{} end
  Retriever(false)
end
end
function fillIce()
update{'Filling with ice.'}
if ice_missing>0 then
  Ice(true)
  while ice_missing>0 do sleep(params.main_delay) update{} end
  Ice(false)
end
end

function auto()
update{}
while true do
  while 10000-maxUran<=params.Umin do
	  Power(false)
	  update{'Almost depleted cells detected. Entering depletion cycle'}
	  sleep(params.excess_ice_delay)
	  retrieve()
   fillUran()
   fillIce()
   if 10000-maxUran<params.Umin then
	update{}
	sleep(params.excess_ice_delay)
	Power(true)
	ti=os.clock()
	sleep_duration=(10000-maxUran)/params.Uspeed+params.depletion_delay
	while os.clock()-ti<sleep_duration do
	 update{}
	 sleep(params.main_delay)
	end
	Power(false)
	update{}
   end
  end
  if (n_slots_free>0 or n_to_withdraw>0) then
   Power(false)
   update{'Empty slots near-depleted/re-enriched cells detected.'}
	  sleep(params.excess_ice_delay)
   retrieve()
   fillUran()
  end
  fillIce()
  while (not (10000-maxUran<=params.Umin)) and n_slots_free==0 and n_to_withdraw==0 do
   update{'In main loop.'}
	  Ice(true)
	  Power(true)
	  sleep(params.main_delay)
  end
  Ice(false)
  Power(false)
end
end
function saveReactors(reactors)
file=fs.open('disk/AR_reactors','w')
for i,reactor in  pairs(reactors) do
  s='Entry{name=\''..reactor.name..'\', target=\''..reactor.target..'\', sensor=\''..reactor.sensor..'\', size=\''..reactor.size..'\', pos=\''..reactor.pos..'\', ice_slots_start=\''..compress(reactor.ice_slots_start)..'\'}'
  file.writeLine(s)
end
file.close()
end
function getSavedReactors()
local reactors = {}
	function Entry (B)/>/> reactors[#reactors+1] = b  end
	dofile("disk/AR_reactors")
	for i, r in pairs(reactors) do
	 r.size=tonumber(r.size)
	end
	return reactors
end

function saveParams(params)
file=fs.open('disk/AR_params','w')
for i,v in  pairs(params) do
  s='Entry{\''..tostring(i)..'\',\''..tostring(v)..'\'}'
  file.writeLine(s)
end
file.close()
end
function getSavedParams()
params = {}
if fs.exists("disk/AR_params") then
	 function Entry (B)/>/> params[b[1]]=tonumber(b[2])  end
	 dofile("disk/AR_params")
	end
	return params
end
if fs.exists('disk/AR_reactors') then
print('Found saved reactors in disk/AR_reactors.\nTo reset and choose reactors, delete the file and reboot.')
reactors=getSavedReactors()
else
print('List of reactors not found. Waiting for human interaction, press enter to proceed.')
read()
pre_reactors=getReactors()
reactors={}
print('Listing reactors, enter \y\+enter to confirm or \'n\'+enter to discard.')
for i, reactor in pairs(pre_reactors) do
  for n, v in pairs(reactor) do print(n..':'..v) end
  r=0 while not (r=='y' or r=='n') do r=tostring(read()) end
  print('Choice registed')
  if r=='y' then print('Keeping reactor for AR.') reactors[i]=reactor end
end
end
aggregateReactors(reactors)
updateReactorsState()
saveReactors(reactors)
print('Reactors saved to disk/AR_reactors')
rs.setOutput(BCbustransceiver_side,true)

if fs.exists('disk/AR_params') then
print('Found operational parameters file.\nTo modify, edit disk/AR_params and save.')
params=getSavedParams()
else
print('List of parameters not found. Waiting for human interaction, press enter to proceed.')
read()
function check_edit(table)
  for i,v in pairs(table) do
   print(i)
   print('set to:'..tostring(v))
   print('Edit?y/n+enter')
   repeat r=read() until (r=='y' or r=='n')
   if tostring(r)=='y' then
   print('Write the desired value, and press enter.')
	v=tonumber(tostring(read()))
   end
   params[i]=v
  end
end
params={}
aggregateReactors(reactors)
updateReactorsState()
check_edit({Umin=20,Uspeed=1,excess_ice_delay=5,depletion_delay=5,main_delay=5})
saveParams(params)
print('Parameters saved to disk/AR_params')
end
aggregateReactors(reactors)
if peripheral.isPresent('top') then if peripheral.getType('top')=='monitor' then monitor=peripheral.wrap('top') term.redirect(monitor) end end
auto()
end
local status, err = pcall(everything)
if not status then rs.setOutput(BCbustransceiver_side,false) print(err) end

Here is the 263 line:

s='Entry{name=\''..reactor.name..'\', target=\''..reactor.target..'\', sensor=\''..reactor.sensor..'\', size=\''..reactor.size..'\', pos=\''..reactor.pos..'\', ice_slots_start=\''..compress(reactor.ice_slots_start)..'\'}'

Here is a screenshoot about it:

Split into new topic.

Can you please put the code in pastebin. It is plagued with code markers. Just copy straight from where you edit it to pastebin then I'll look at it

basically it means you have a blank value that you are trying to add to the others…

I found that the best way to find the error is to add some commented code in just before the error…

---[[
print("val 1 ".. firsttext)
print("val 2 ".. secondtext)
--]]

then your error will move to the line of code that has your blank table / string or value in it. Adjust the code untill the value works correctly and then you can make the debugging code commented (just in case of future problems) or select the commented debug code and delete it.

My prefered method is to leave the code in but just make it –[[ Commented debug code. ( —[[ uncommented block )