File

net.server: Add a predrain callaback just before writes Allows sneaking in things in the write buffer just before it's sent to the network stack. For example ack requests, compression flushes or other things that make sense to send after stanzas or other things. This ensures any additional trailing data sent is included in the same write, and possibly the same TCP packet. Other methods used such as timers or nextTick might not have the same effect as it depends on scheduling.

local data = {}
local getinfo = debug.getinfo;
local function linehook(ev, li)
	local S = getinfo(2, "S");
	if S and S.source and S.source:match"^@" then
		local file = S.source:sub(2);
		local lines = data[file];
		if not lines then
			lines = {};
			data[file] = lines;
			for line in io.lines(file) do
				lines[#lines+1] = line;
			end
		end
		io.stderr:write(ev, " ", file, " ", li, " ", lines[li], "\n");
	end
end
debug.sethook(linehook, "l");