init.lua

-- WRITE CHANGES to FILE

local write_gofile = function() 
	local output = ''
	for name, coords in pairs(GONETWORK) do
		output = output..name..':'..coords.x..','..coords.y..','..coords.z..';'
	end
	local f = io.open(minetest.get_worldpath()..'/destinations.go', "w")
		f:write(output)
		io.close(f)
end



GONETWORK = {}
local gonfile = io.open(minetest.get_worldpath()..'/destinations.go', "r")  
if gonfile then
	local contents = gonfile:read()
	io.close(gonfile)
	if contents ~= nil then 
		local entries = contents:split(";") 
		for i,entry in pairs(entries) do
			local goname, coords = unpack(entry:split(":"))
			local p = {}
				p.x, p.y, p.z = string.match(
				coords, "^([%d.-]+)[, ] *([%d.-]+)[, ] *([%d.-]+)$"
				)
			if p.x and p.y and p.z then
				GONETWORK[goname] = 
				{x = tonumber(p.x),y= tonumber(p.y),z = tonumber(p.z)}
			end
		end
	end
end



-- CHAT COMMANDS

minetest.register_chatcommand("setgo", {
	params = "<name>",
	description = "set /go destination",
	privs = {server=true},
	func = function(name, param)
		local target = minetest.get_player_by_name(name)
		if target then
			GONETWORK[param] = target:getpos()
			write_gofile()
			minetest.chat_send_player(name, "/go "..param.." set")
			return
		end
	end,
})



minetest.register_chatcommand("go", {
	params = "<goname>",
	description = "go to destination",
	func = function(name, param)
		if GONETWORK[param] == nil then
			minetest.chat_send_player(name, "no such destination")
			return
		end
		teleportee = minetest.get_player_by_name(name)
		teleportee:setpos(GONETWORK[param])
	end,
})



minetest.register_chatcommand("delgo", {
	params = "<name>",
	description = "delete /go destination",
	privs = {server=true},
	func = function(name, param)
		if GONETWORK[param] then 
			GONETWORK[param] = nil
			write_gofile()
		end
	end,
})



minetest.register_chatcommand("listgo", {
	params = "<goname>",
	description = "list all go destinations",
	func = function(name, param)
		for go, coords in pairs(GONETWORK) do
			minetest.chat_send_player(
			name, "/go "..go.. ' at '..coords.x..','..coords.y..','..coords.z
			)
		end		
	end,
})