Builder 2.0

--[[
    Buil everything from a string char.

    Commands characters:
        - moving:
            - i: move turtle forward
            - j: turn turtle to left
            - k: move turtle backward
            - l: turn turtle to right
            - u: move turtle up
            - n: move turtle down

        - building:
            - 0: select and place down the item in slot 1
            - 1: select and place down the item in slot 2
            - 2: select and place down the item in slot 3
            - 3: select and place down the item in slot 4
            - 4: select and place down the item in slot 5
            - 5: select and place down the item in slot 6
            - 6: select and place down the item in slot 7
            - 7: select and place down the item in slot 8
            - 8: select and place down the item in slot 9
            - 9: select and place down the item in slot 10
            - a: select and place down the item in slot 11
            - b: select and place down the item in slot 12
            - c: select and place down the item in slot 13
            - d: select and place down the item in slot 14
            - e: select and place down the item in slot 15
            - f: select and place down the item in slot 16
            - z: place down the item in last selected slot
            - x: search for the first slot not empty and place down it (useful for big constructions with the same block type and you have the turtle filled with the same block)
]]--

-- get args
local args = {...}

local strCommand = args[1]

local function getConstructionSlot()
    for i = 1,16 do
        if turtle.getItemCount(i) > 0 then
            return i
        end
    end

    return 0
end

local function selectConstructionSlot()
    local slot = getConstructionSlot()

    if slot > 0 then
        turtle.select(slot)
    else
        printError("No construction material found")
    end
end

local function turtleMove(command)
    if command == 'i' then
        return turtle.forward()
    elseif command == 'k' then
        return turtle.back()
    elseif command == 'j' then
        return turtle.turnLeft()
    elseif command == 'l' then
        return turtle.turnRight()
    elseif command == 'u' then
        return turtle.up()
    elseif command == 'n' then
        return turtle.down()
    end

    return false
end

local function selectInventory(command)
    if command == '0' then
        return turtle.select(1)
    elseif command == '1' then
        return turtle.select(2)
    elseif command == '2' then
        return turtle.select(3)
    elseif command == '3' then
        return turtle.select(4)
    elseif command == '4' then
        return turtle.select(5)
    elseif command == '5' then
        return turtle.select(6)
    elseif command == '6' then
        return turtle.select(7)
    elseif command == '7' then
        return turtle.select(8)
    elseif command == '8' then
        return turtle.select(9)
    elseif command == '9' then
        return turtle.select(10)
    elseif command == 'a' then
        return turtle.select(11)
    elseif command == 'b' then
        return turtle.select(12)
    elseif command == 'c' then
        return turtle.select(13)
    elseif command == 'd' then
        return turtle.select(14)
    elseif command == 'e' then
        return turtle.select(15)
    elseif command == 'f' then
        return turtle.select(16)
    end

    return false
end

for i = 1, #strCommand do
    local c = strCommand:sub(i, i)

    if c == 'z' or selectInventory(c) then
        -- place
        turtle.placeDown()
    elseif c == 'x' then
        -- place
        selectConstructionSlot()
        turtle.placeDown()
    elseif turtleMove(c) then
        -- move
    else
        -- invalid char
        print("Invalid char command "..c)
    end
end