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