yaml-merge

#!/usr/bin/env lua5.1

local yaml = require "yaml";

function merge_in(t1, t2, depth)

	depth = depth or 0;

	if type(t1) == "table" and type(t2) == "table" then

		local array = {};

		if depth < 2 then -- numeric

			for i,v in ipairs(t2) do

				array[v] = true;

				table.insert(t1, v);

			end

		end

		for k,v in pairs(t2) do -- non-numeric

			if not(type(k) == "number" and array[v]) then -- fixme, merge non-numeric

				t1[k] = merge_in(t1[k], v, depth + 1);

			end

		end

	elseif t2 ~= nil then

		t1 = t2;

	end

	return t1;

end

local out = {};

for i, fn in ipairs(arg) do

	local f = assert(io.open(fn, "r"));

	merge_in(out, yaml.load(f:read("*a")));

	f:close();

end

print(yaml.dump(out));