How do I count the line count of a script?

I'm working on making a plugin that shows info on a script when it is selected, and know how to test for the selection and get the name, but how do I count how many lines it has?

You would have to get the source of the script(as Spongocardo stated) and reconstruct the entire text-I had already done something like this. This is heavily based off of BuildIn Libraries' Helper Library.

function getSource(s)
	local lines = {};
	local str = "";
	for i = 1, string.len(s.Source) do
		if (string.sub(s.Source, i, i) == "\n") then
			lines[#lines+1] = str;
			str = "";
		else
			str = str..string.sub(s.Source, i, i);
		end
	end

	if (str ~= "") then
		lines[#lines+1] = str;
	end
	return lines;
end

Now you could do #lines to find how many lines it has.