CC Turtle Lib

-- Let dir 0-3 be {N, E, S, W}
-- east is positive x, south is positive z

directions = {'north','east','south','west'}

default = {x=0,y=0,z=0,direction=0}

function save(table,filename)
    local file = fs.open(filename,"w")
    file.write(textutils.serialize(table))
    file.close()
end

function load(filename)
    local file = fs.open(filename,"r")
    local data = textutils.unserialize(file.readAll())
    file.close()
    return data
end

function dir(dir)
    for i, v in pairs(directions) do
        if string.lower(dir) == v then
            return i
        end
    end
    return false
end

function forward(dist)
    if not turtle then return end
    pos = getPos('locale')
    if turtle.forward() then
        dx = math.floor(math.cos((pos['direction']-1)*math.pi/2))
        dz = -math.floor(math.cos(pos['direction']*math.pi/2))
        pos['x'] = pos['x'] + dx
        pos['z'] = pos['z'] + dz
        save(pos,'locale')
        return true
    end
    return false
end
fwd = forward

function right()
    if not turtle then return end
    pos = getPos('locale')
    if turtle.turnRight() then
        pos['direction'] = (pos['direction'] + 1)%4
        save(pos,'locale')
        return true
    end
    return false
end

function left()
    if not turtle then return end
    pos = getPos('locale')
    if turtle.turnLeft() then
        pos['direction'] = (pos['direction'] - 1)%4
        save(pos,'locale')
        return true
    end
    return false
end

function up()
    if not turtle then return end
    pos = getPos('locale')
    if turtle.up() then
        pos['y'] = pos['y'] + 1
        save(pos,'locale')
        return true
    end
    return false
end

function down()
    if not turtle then return end
    pos = getPos('locale')
    if turtle.down() then
        pos['y'] = pos['y'] - 1
        save(pos,'locale')
        return true
    end
    return false
end

function getPos()
    if not turtle then return end
    if not fs.exists('locale') then
        save(default, 'locale')
    end
    return load('locale')
end