How to push sokoban boxes in PICO-8

sokoban_pushing.p8

function _init()
 player = {
 	x=1,
 	y=1,
	direction = 5
 }
 	poke(0x5f2c,3)
end

directions = {
	left = 1,
	right = 2,
	up = 3,
	down = 4,
	none = 5
}
dir_table = {
	{-1,0},{1,0},{0,-1},{0,1},{0,0}
}

function _update()
	pressed = false
	if btnp(0) then
		player.direction = directions.left
		pressed = true
	elseif btnp(1) then
		player.direction = directions.right
		pressed = true
	elseif btnp(2) then
		player.direction = directions.up
		pressed = true
	elseif btnp(3) then
		player.direction = directions.down
		pressed = true
	end
  -- if we pressed move
	if pressed then
		local newx = player.x+dir_table[player.direction][1]
		local newy = player.y+dir_table[player.direction][2]

		-- not a wall
		if mget(newx,newy) ~= 1 then
			-- check if it is a box
			if mget(newx,newy) > 15 then
				-- check if the box can move as well
				local newbx = newx+dir_table[player.direction][1]
				local newby = newy+dir_table[player.direction][2]
				if mget(newbx,newby) == 0 or mget(newbx,newby) == 4 then
					-- move box
					-- save tile first
					local tile = mget(newx,newy)
					mset(newbx,newby,tile)
					mset(newx,newy,0)
					-- move player
					player.x = newx
					player.y = newy
				end
			else  -- not box, so move
				player.x = newx
				player.y = newy
			end
		end
	end
end

function _draw()
	cls()
  -- I used tile 1 as walls, 2 as the player, 3 as the boxes, for as the spots
  -- to push on
	local tileascii = {"[]","","█","()"}
	local tilecolor = {1,1,4,9}
	print("웃", player.x*8, player.y*8,6)
	for i=0,8 do
		for j=0,6 do
			local tile = mget(i,j)
			if tile ~= 0 then
					print(tileascii[tile],i*8,j*8,tilecolor[tile])
				end
			else
				--print(".",i*8,j*8,1)
			end
		end
	end
 end

Made for my Kofi article about a sokoban word puzzle game: https://ko-fi.com/post/PICO-ASCII-Jam-0--In-the-beningi-G2G11RQH04