pathTest.lua

local keepRunning=true
local borderBlock="minecraft:glass"

local turnedRightLast=false
local shouldGoDown=false


local x=0
local y=0
local z=0

local function goForward() write("F") return turtle.forward() end
local function turnRight() write("R") turtle.turnRight() end
local function turnLeft() write("L") turtle.turnLeft() end
local function detectBorder() local success, data = turtle.inspect() if success then if data.name == borderBlock then return true else return false end end end
local function detectBorderUp() local success, data = turtle.inspectUp() if success then if data.name == borderBlock then shouldGoDown=true end end end
local function detectDown() local success, data = turtle.inspectDown() if success then return data.name end end
local function suckAll () turtle.suck() turtle.suckDown() turtle.suckUp() end
local function goUp() write("U")  y=y+1 return turtle.up() end
local function goDown() write("D") y=y-1 return  turtle.down() end
local function upOrDown ()
    if detectBorderUp() then

    end
end
local function turnAround () turnRight() turnRight() end

local function detectCorner()
    -- Look forward
    local borderForward = detectBorder()
    -- Look left
    turnLeft()
    local borderLeft = detectBorder()
    -- turn Right and look
    turnRight()
    local borderRight = detectBorder()
    -- turn back left (so we are looking forward)
    turnLeft()
    if (borderForward and borderLeft) or (borderForward and borderRight) then
        if shouldGoDown then
            goDown()
        else
            goUp()
        end
        turnAround()
    end
end



while keepRunning do
    while not turtle.detect() do
        -- White we didn't detect anything
        goForward()
    end
    detectCorner()

end



-- -- go forward to border
    -- -- at border turn right
    -- -- try to go forward.  If not forward, and not at top, go up




    -- if not goForward() then
    --     if detectBorder() then
    --         write("B")
    --         if not turnedRightLast then
    --             write("rt")
    --             if not uTurnRight() then
    --                 if not detectedTop then
    --                     if not goUp() then
    --                         if detectBorderUp() then
    --                             detectedTop=true
    --                             goDown()
    --                         end
    --                     else
    --                         uTurnRight()
    --                         uTurnRight()
    --                     end
    --                 uTurnLeft()
    --                 else
    --                     goDown()

    --                 end
    --             end
    --         turnedRightLast=true
    --      else
    --             write("lt")
    --             if not uTurnLeft() then
    --                 goUp()
    --                 uTurnRight()
    --             end
    --             turnedRightLast=false
    --      end
    --     else
    --         turtle.dig()
    --         suckAll()
    --     end
    -- end