Mapreader

I've created an api that takes a table of multiline strings and turns it into a function that moves the turtle from start to end. Mark the starting position with "X", continue the path with #, and go up and down by using "U" or "D".

nerd explination

In reality, my code returns a table. I simply used the __call metamethod to make it act like a function. It recognises #, U, and D as places to move to, and then will move up from the space of U or down from the space of D.

There is only one function: mapreader.path( table[, yield] )
if yield is true, the function will need to be called again for each movement, allowing you to add more code if you like.

the code

function path( tMaps, _yield )
	--Find start
	local function findStart()
		for k, sMap in ipairs( tMaps ) do
			local l = 1
			for line in sMap:gmatch( '[^\r\n]+' ) do
				for i = 1, #line do
					if line:sub( i, i ):upper() == "X" then
						return {x = i, y = l, z = k}
					end
				end
				l = l + 1
			end
		end
	end
	--update removes already used path bits
	local function update( tbl )
		local l = 1
		local newString = {}
		local oldChar
		for line in tMaps[ tbl.z ]:gmatch( '[^\r\n]+' ) do
			if l == tbl.y then
				newString[l] = line:sub( 1, tbl.x - 1 ).." "..line:sub( tbl.x + 1, #line )
				oldChar = line:sub( tbl.x, tbl.x )
			else
				newString[l] = line
			end
			l = l + 1
		end
		return table.concat( newString, "\n" ), oldChar
	end
	--orient function
	local face = "up"
	local function orient( direction )
		if face == "up" and direction == "up" then
			return
		elseif face == "up" and direction == "right" then
			turtle.turnRight()
			face = "right"
		elseif face == "up" and direction == "left" then
			turtle.turnLeft()
			face = "left"
		elseif face == "up" and direction == "down" then
			turtle.turnRight()
			turtle.turnRight()
			face = "down"
		elseif face == "right" and direction == "up" then
			turtle.turnLeft()
			face = "up"
		elseif face == "right" and direction == "right" then
			return
		elseif face == "right" and direction == "left" then
			turtle.turnLeft()
			turtle.turnLeft()
			face = "left"
		elseif face == "right" and direction == "down" then
			turtle.turnRight()
			face = "down"
		elseif face == "left" and direction == "up" then
			turtle.turnRight()
			face = "up"
		elseif face == "left" and direction == "right" then
			turtle.turnRight()
			turtle.turnRight()
			face = "right"
		elseif face == "left" and direction == "left" then
			return
		elseif face == "left" and direction == "down" then
			turtle.turnLeft()
			face = "down"
		elseif face == "down" and direction == "up" then
			turtle.turnLeft()
			turtle.turnLeft()
			face = "up"
		elseif face == "down" and direction == "right" then
			turtle.turnLeft()
			face = "right"
		elseif face == "down" and direction == "left" then
			turtle.turnRight()
			face = "left"
		elseif face == "down" and direction == "down" then
			return
		end
	end
	--Find next position
	local function findNext( tbl )
		local oldChar
		tMaps[ tbl.z ], oldChar = update( tbl )
		local l = 1
		local compare = {
			D = true,
			U = true,
			["#"] = true,
			d = true,
			u = true,
		}
		--Check current level
		for line in tMaps[ tbl.z ]:gmatch( '[^\r\n]+' ) do
			if l == tbl.y - 1 and compare[ line:sub( tbl.x, tbl.x ) ] then
				--turtle should move "up"
				return function() orient( "up" ) return turtle.forward() end, {x = tbl.x, y = tbl.y - 1, z = tbl.z}
			elseif l == tbl.y and compare[ line:sub( tbl.x - 1, tbl.x - 1 ) ] then
				--turtle should move "left"
				return function() orient( "left" ) return turtle.forward() end, {x = tbl.x - 1, y = tbl.y, z = tbl.z}
			elseif l == tbl.y and compare[ line:sub( tbl.x + 1, tbl.x + 1 ) ] then
				--turtle should move "right"
				return function() orient( "right" ) return turtle.forward() end, {x = tbl.x + 1, y = tbl.y, z = tbl.z}
			elseif l == tbl.y + 1 and compare[ line:sub( tbl.x, tbl.x ) ]then
				--turtle should move "down"
				return function() orient( "down" ) return turtle.forward() end, {x = tbl.x, y = tbl.y + 1, z = tbl.z}
			elseif oldChar:upper() == "U" then
				return function() return turtle.up() end, {x = tbl.x, y = tbl.y, z = tbl.z + 1}
			elseif oldChar:upper() == "D" then
				return function() return turtle.down() end, {x = tbl.x, y = tbl.y, z = tbl.z - 1}
			end
			l = l + 1
		end		
	end
	local place = findStart()
	local path = {}
	while place do
		path[#path + 1], place = findNext( place )
	end
	path.x = 1
	path.yield = _yield
	local mt = {
	__call = function()
		if path[ path.x ] and path.yield then
			local success = path[ path.x ]()
			path.x = path.x + 1
			return success
		elseif path[ path.x ] then
			repeat
				path[ path.x ]()
				path.x = path.x + 1
			until not path[ path.x ]
		else
			return false
		end
	end,
	}
	setmetatable( path, mt )
	return path
end

pastebin get XPYenpku mapreader

Screenshots & example code coming soon