performing part of a function once in lua

Question

i am currently playing ftb on minecraft and have gotten into the mod called computer craft, that uses lua as its programing language. i have written a basic script so far for clearing out rooms with 3 directions and any size. the directions are Right Left and Center. the center is for if the person wants the door to be the center of the room. but i am having trouble performing a function i made along wit a bit of code one in another function once.

this is the function i want to perform once in another function

function hwd()
 for m = 1,w*0.5 do
 turtle.dig()
 echest()
 turtle.forward()
 end
end 

this is the main function

function cntr()
 if d == "c" then
 for p = 1,w do
 length()
 turtle.turnRight()
 turtle.dig()
 echest()
 turtle.forward()
 turtle.turnLeft()
 end
 end
end

the part i need to perform once in on the first loop will look like this

turtle.turnLeft()
hwd()
turtle.turnRight()

after "for p = 1,w do" and before "length()"

i have the script working without the center part but need to ad this part. any help would be greatly appreciated.

for the working script head to: http://pastebin.com/Uf5Li1Cy

for the script with the added center part head to: http://pastebin.com/AqZHQrFb

• hugomg: What is the error that you are currently getting?
• Etan Reisner: Is the question here how to only call hwd() during the first iteration of the loop?
• SubTox1c: i am getting no error since the code isnt finished for me to execute it but yes and no Etan i want it to call the hole function but want hwd() to be called on the first iteration

Answer 1

Does the loop always execute at least once? Then simply put that code right before the loop.

 -- do the special thing
 for p = 1,w do

If not, you can put it the loop guarded by a boolean:

 local didTheSpecialThing = false
 for p = 1,w do
 if not didTheSpecialThing then
 -- do the special thing
 didTheSpecialThing = true
 end
 ...

Or you could put it before the loop, with a check to see if it needs to be executed:

 if w > 0 then
 -- do the special thing
 end
 for p = 1,w do

• SubTox1c: Mud i thank you greatly. The last 1 worked perfectly now all i need to do is add in a mob/gravel detection bit and maybe block lite detect for torches. now i can do the finishing touches to my turtle script. i cant thank you enough.