[Question]How to edit the existing Excavate script?

i'd like to try and edit the existing excavate script. my goal here is to add a filter to it. could anybody help get me started or point me in the right direction?

i'm trying to get a turtle to destroy everything like in excavate except for the first few blocks in its inventory. i know it should look something like this

while not move forward
  if turtle.compareforward() = false
    then
	  turtle.select(2)
    else
	  turtle.dig()
else
turtle.forward()
end

i know this script is awful and full of bugs but its how i'd think it may look. something similar perhaps. i know it doesn't compare the other slots yet, but maybe w/ some help i can get this working.

thanks for your time!

You won't be able to edit it because it's inside the rom folder which is un-writable.

Copy it to your turtle as excavate and then edit it from there.

cp rom/programs/turtle/excavate excavate

ah okay, that'll make it easier for me! but now for the filtering. any idea how that may look? what confuses me is getting it to check multiple slots :(/>

Use a simple for loop:

inventoryToStartAt = 3
inventoryToEndAt = 9

for i = inventoryToStartAt, inventoryToEndAt do
    -- What do you mean by destroy the inventories? Do you mean drop the blocks?
    turtle.select(i)
    turtle.drop()
end

no it doesn't have to drop anything. just NOT break specific blocks in its inventory, or return them either i guess when it goes back to refuel/deposit. i'm looking at the excavate script now & its pretty confusing :(/>
i figure i just need to add a function near the place where it tries to dig. but i just realized that the default excavate stops when it can't dig anymore, so i'm wondering if putting a filter on it will cause it to stop prematurely >.<

Oh, ok then you need the block you don't want the turtle to break in the turtle in any slot and then you turtle.compare() / compareUp() compareDown()

turtle.select(16) -- lets say you put the block you don't want to break in slot 16 (if you're not using tekkit....)
if turtle.compare() or turtle.compareUp() or turtle.compareDown() then
    -- code if it is that block
else
   -- code if it isn't
end

Something like that?

yes exactly, so in the else section would i have it switch to slot 2 and have another if statement in there? and then lets say in that If statement in that Else i'd have it break? so like:

turtle.select(1) -- lets say you put the block you don't want to break in slot 1
if turtle.compare() or turtle.compareUp() or turtle.compareDown() then
    -- move along
else
   turtle.select(2)
	  if turtle.compare() or turtle.compareUp() or turtle.compareDown()
	  then
		 -- move along
	  else
		 turtle.select(3)
		   if turtle.compare() or turtle.compareUp() or turtle.compareDown()
			  then
				  -- move along
			  else
				    turtle.dig()
end

sorry i know thats REALLY bad but i'm trying to learn as i go!