Problem with a function

i wantet to build a litte funtion for my turtle, but this code:

function GeheZu (zielx , zielz)
print(zielx)
print(zielz)
print("gehe zu")
while x < zielx and x < 18 do
  turtle.forward()
  x = x + 1
  sleep(0.5)
end
while x > zielx and x > 1 do
  turtle.back()
  x = x - 1
  sleep(0.5)
end
while z < zielz and z <3 do
  turtle.up()
  z = z + 1
  sleep(0.5)
end
while z > zielz and z > 1 do
  turtle.down()
  z = z - 1
  sleep(0.5)
end

print("fertig")
end

produce this error:

test:20: attemt to compare __lt on nil and number

hope someone can help me

this is just a function so where is the line 20 of your code ?

Since this is a single function and we can't tell which line is line 20 of your code, I'm going to take a guess and say that either the variables x or z doesn't exist or hasn't been initialized before you call this function.

It would be of great help if you posted your full code.

1. Indent your code.
2. Show us line 20.
3. You probably havnt set any variables to be anything.

sry :rolleyes:/>
here the complete code

x, z = 1
iForm = 0
iEffekt = 0
iFarbe = 0
iStart = 0
function GeheZu (zielx , zielz)
print(zielx)
print(zielz)
print("gehe zu")
while x < zielx and x < 18 do
  turtle.forward()
  x = x + 1
  sleep(0.5)
end
while x > zielx and x > 1 do
  turtle.back()
  x = x - 1
  sleep(0.5)
end
while z < zielz and z <3 do
  turtle.up()
  z = z + 1
  sleep(0.5)
end
while z > zielz and z > 1 do
  turtle.down()
  z = z - 1
  sleep(0.5)
end

print("fertig")
end
-- Auswahlmenü --
shell.run("clear")
print("Waehle eine Form:")
print("1 - Kugel - klein")
print("2 - Kugel - gross")
print("3 - zerstreut")
print("4 - Stern")
print("5 - Creeper")
print("")
write("Gebe eine Zahl (1-5) ein: ")
while iForm == 0 do
form1 = io.read()
form = (form1 + 0)
if form >= 1 and form <= 5 then
  iForm = 1
else
  print("Falsche Eingabe! Bitte eine Zahl 1-5 eingeben!")
end
end
shell.run("clear")
print("Waehle einen Effekt:")
print("1 - keiner")
print("2 - Glitzern")
print("3 - Schweife")
print("")
write("Gebe eine Zahl (1-3) ein: ")
while iEffekt == 0 do
effekt1 = io.read()
effekt = (effekt1 + 0)
if effekt >= 1 and effekt <= 3 then
  iEffekt = 1
else
  print("Falsche Eingabe! Bitte eine Zahl 1-3 eingeben!")
end
end
shell.run("clear")
print("Waehle eine Farbe:")
print("1  - Weiss	   9  - Hellgrau")
print("2  - Orange	  10 - Tuerkis")
print("3  - Magenta	 11 - Violett")
print("4  - Hellblau	12 - Blau")
print("5  - Gelb		13 - Braun")
print("6  - Hellgruen   14 - Gruen")
print("7  - Rosa		15 - Rot")
print("8  - Grau		16 - Schwarz")
print("")
write("Gebe eine Zahl (1-16) ein: ")
while iFarbe == 0 do
farbe1 = io.read()
farbe = (farbe1 + 0)
if farbe >= 1 and farbe <= 16 then
  iFarbe = 1
else
  print("Falsche Eingabe! Bitte eine Zahl 1-16 eingeben!")
end
end
-- Startbefehl --
-- Schwarzpulver aufnehmen --
GeheZu(5,1)
turtle.select(1)
turtle.turnRight()
turtle.suck()
turtle.turnLeft()

Ah there is the problem. On the first line you do x, z = 1. This sets x to 1, but z is not set to anything, meaning it becomes nil. Try this instead: x, z = 1, 1.

that was the problem!

thank you :)/>