function core.parse_pos(param)
	local p = {}
	local playerpos = core.localplayer:get_pos()
	p.x, p.y, p.z = string.match(param, "^([~|%d.-]+)[, ] *([~|%d.-]+)[, ] *([~|%d.-]+)$")
	for k, v in pairs(p) do
		if p[k] == "~" then
			p[k] = playerpos[k]
		else
			p[k] = tonumber(v)
		end
	end
	if p.x and p.y and p.z then
		return true, vector.round(p)
	end
	return false, "Invalid position (" .. param .. ")"
end 

function core.parse_relative_pos(param)
	local success, pos = core.parse_pos(param:gsub("~", "0"))
	if success then pos = vector.round(vector.add(core.localplayer:get_pos(), pos)) end
	return success, pos
end 

function core.switch_to_item(item)
	for index, stack in ipairs(core.get_inventory("current_player").main) do
		if stack:get_name() == item then
			core.localplayer:set_wield_index(index - 1)
			return true
		end
	end
	return false
end

function core.get_pointed_thing()
	local pos = core.camera:get_pos()
	local pos2 = vector.add(pos, vector.multiply(core.camera:get_look_dir(), 5))
	local ray = core.raycast(pos, pos2, true, true)
	
	return ray:next()
end