gistfile1.lua

-- For use with the ComputerCraft Minecraft mod. http://computercraft.info/
--
-- To use, just get a mining turtle then create a script
-- do: edit miner
-- then write this script(I know, tedious).
-- Once finished just do `miner` to start finding diamonds!

-- Keeps track of up and down movements
downCounter = 0
upCounter = 0
maxLevelSearch = 15

-- Return true if there's a bedrock block under us
atBedrock = function(slot)
  local bedrockItem = turtle.select(slot)

  if bedrockItem then
    if turtle.detectDown() then
      return turtle.compareDown()
    end
  end

  return false
end

-- Move down, with room for people to walk
moveDown = function()
  turtle.digDown()
  if turtle.down() then
    downCounter = downCounter + 1
  end

  turtle.dig()
  turtle.forward()
  turtle.dig()
end

-- Move up in the same fashion built from move down
moveUp = function()
  -- We may need to dig also
  turtle.back()
  if turtle.up() then
    upCounter = upCounter + 1
  end
end

clearInventory = function(count)
  for i = 1, count do
    turtle.select(i)
    turtle.drop()
  end

  return true
end

search = function(width, depth)
  -- Most bugs have been fixed, but some things are 
  -- still random. Rogue turtles happen a lot so be ready to lose it.

  -- Counters
  local movementsCounter = 0
  local widthCounter = 0
  local searchLevelCounter = 0

  -- Dig and move half of the width
  moveHalfWidth = function()
    repeat
      turtle.dig()
      turtle.forward()
      movementsCounter = movementsCounter + 1
    until movementsCounter >= width/2
    movementsCounter = 0
  end

  -- Move to right side from middle, and go up one level
  nextLevel = function()
    turtle.turnRight()
    moveHalfWidth()

    turtle.digUp()
    turtle.up()
    turtle.turnLeft()
  end

  -- Moves to the middle from the far left, created by the width level loop
  moveToMiddleFromLeft = function()
    turtle.turnRight()
    moveHalfWidth()
    -- Do an extra move since the main
    -- width level loop ends up ready for the next forward depth dig
    turtle.dig()
    turtle.forward()
    turtle.dig()
    turtle.forward()
    turtle.turnLeft()
  end

  -- Dig forward a depth minus the single block depth used to
  -- track across width
  digDepthLevel = function()
    repeat
        turtle.dig()
        turtle.forward()
        movementsCounter = movementsCounter + 1
      until movementsCounter >= depth - 1
      movementsCounter = 0
  end

  -- Rotates the turtle to dig depth levels
  rotate = function(side)
    if side == "left" then
      turn = turtle.turnLeft
    else
      turn = turtle.turnRight
    end

    turn()
    turtle.dig()
    turtle.forward()
    turn()
  end

  -- Move to right side to start searching
  turtle.turnRight()
  moveHalfWidth()
  turtle.turnLeft()

  repeat -- Start level count loop
    repeat -- Start width level loop
      -- Dig one depth level forward
      digDepthLevel()
      widthCounter = widthCounter + 1

      -- Turn around to do reverse width level
      rotate("left")

      -- Dig one level reverse
      digDepthLevel()
      widthCounter = widthCounter + 1

      -- Turn around to do forward width level
      rotate("right")
    until widthCounter >= width + 1

    -- Move back to middle space
    moveToMiddleFromLeft()

    -- If we havent reached max level yet go up to next level
    searchLevelCounter = searchLevelCounter + 1
    if searchLevelCounter < maxLevelSearch then
      widthCounter = 0 -- Reset
      nextLevel()
    end
  until searchLevelCounter >= maxLevelSearch -- End level count loop

  return true
end

init = function()
  repeat
    moveDown()
  until atBedrock(1)
  print("We're at bedrock. It is " .. downCounter .. " blocks down.")

  repeat
    -- Move up 4 levels, to keep away from bedrock holes
    moveUp()
  until upCounter >= 4
  downCounter = downCounter - 4
  upCounter = 0 -- Reset

  print("Clearing inventory to start searching.")
  clearInventory(9) -- 9 is the inv cap for -1.33 and 16 is +1.33

  print("Now searching.")
  search(15, 15)

  -- Do something cool here to get rid of cobblestone and other
  -- useless blocks, only return with good shit.

  print("Going back up to surface, " .. downCounter .. " blocks up.")
  repeat
    -- This is hard as fuck to figure out, for some reason it's incredibly random
    moveUp()
  until upCounter >= downCounter - 1
end
init()