CC Compas

--
-- Compas
-- Get Turtle orientation (facing north, east, south or west)
-- ComputerCraft 1.76
-- Require Turtle
--
-- author: SukaiPoppuGo
-- licence: CC BY-NC-SA 4.0
-- https://creativecommons.org/licenses/by-nc-sa/4.0/
--

slot = ...

if not slot or not tonumber(slot) or not turtle.select(tonumber(slot)) then
    print([[Usage: compas <slot>
slot provided by a block with facing block.state]])
    return false
end

--setup
turtle.select(tonumber(slot))
turtle.placeUp()
local b,d,s = turtle.inspectUp()

if not b then
    print(s)
    return false
end

local dir2num = {
    ["north"]=1,
    ["east"]=2,
    ["south"]=3,
    ["west"]=4,
}
local num2dir = {
    "north",
    "east",
    "south",
    "west",
}

--Database
local tip = {
--forward
    ["minecraft:brick_stairs"]=0,
    ["minecraft:sandstone_stairs"]=0,
    ["minecraft:red_sandstone_stairs"]=0,
    ["minecraft:stone_brick_stairs"]=0,
    ["minecraft:nether_brick_stairs"]=0,
    ["minecraft:oak_stairs"]=0,
    ["minecraft:dark_oak_stairs"]=0,
    ["minecraft:acacia_stairs"]=0,
    ["minecraft:spruce_stairs"]=0,
    ["minecraft:birch_stairs"]=0,
    ["minecraft:jungle_stairs"]=0,
    ["minecraft:quartz_stairs"]=0,
--inverted
    ["minecraft:chest"]=2,
    ["minecraft:furnace"]=2,
    ["minecraft:trapped_chest"]=2,
    ["minecraft:ender_chest"]=2,
    ["minecraft:dropper"]=2,
    ["minecraft:dispenser"]=2,
    ["minecraft:powered_repeater"]=2,
    ["minecraft:unpowered_repeater"]=2,
    ["minecraft:unpowered_comparator"]=2,
    ["minecraft:pumpkin"]=2,
    ["minecraft:lit_pumpkin"]=2,
    ["computercraft:CC-Computer"]=2,
    ["computercraft:CC-command_computer"]=2,
    ["computercraft:CC-Peripheral"]=2,
--ccw
    ["minecraft:anvil"]=-1,
    ["computercraft:CC-Turtle"]=-1,
    ["computercraft:CC-TurtleAdvanced"]=-1,
}


if d and d.state and d.state.facing then
    if tip[d.name] then
        -- local sDir = num2dir[((dir2num[d.state.facing]+tip[d.name]-1)%4)+1]

        local nRawDir = dir2num[d.state.facing] -- as north=1, east=2, south=3, west=4
        -- Correction according to how the block is positioned
        local nCorrect = nRawDir + tip[d.name]
        -- Determine the correct index by modulo
        local sDir = num2dir[((nCorrect-1)%4)+1]
        print(sDir)
        return sDir
    else
        print(string.format("Please update database with %s", d.name))
        return false
    end
else
    print(string.format("%s has no block.state.facing property", d.name))
    return false
end