map reading

function path( mstring, _yield )
	--Find start
	local function findStart()
		local l = 1
		for line in mstring:gmatch( '[^\r\n]+' ) do
			for i = 1, #line do
				if line:sub( i, i ) == "X" then
					return {x = i, y = l}
				end
			end
			l = l + 1
		end
	end
	--update removes already used path bits
	local function update( tbl )
		local l = 1
		local newString = {}
		for line in mstring:gmatch( '[^\r\n]+' ) do
			if l == tbl.y then
				newString[l] = line:sub( 1, tbl.x - 1 ).." "..line:sub( tbl.x + 1, #line )
			else
				newString[l] = line
			end
			l = l + 1
		end
		return table.concat( newString, "\n" )
	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 )
		mstring = update( tbl )
		local l = 1
		for line in mstring:gmatch( '[^\r\n]+' ) do
			if l == tbl.y - 1 and 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}
			elseif l == tbl.y and 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}
			elseif l == tbl.y and 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}
			elseif l == tbl.y + 1 and 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}
			end
			l = l + 1
		end
	end

	local place = findStart()
	local path = {}
	while true do
		path[#path + 1], place = findNext( place )
		if not place then
			break
		end
	end
	path.yield = _yield
	path.go = coroutine.create( function()
		for _, move in ipairs( path ) do
			local success = move()
			if path.yield then
				coroutine.yield( success )
			end
		end
	end )
	local mt = {
		__call = function()
			return coroutine.resume( path.go ) or coroutine.status( path.go )
		end,
	}
	setmetatable( path, mt )
	return path
end

os.loadAPI( "mapreader" )
local map = [[
X####
		# --I give up. Stupid spacing
#####
]]
local move = mapreader.path( map, false )
print( "path created" )
move()