diff -r 000000000000 -r 0757d85e604b yaml-merge
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/yaml-merge	Sat Dec 17 17:08:33 2011 +0000
@@ -0,0 +1,39 @@
+#!/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(t1) do
+				array[v] = true;
+				t1[i] = nil;
+			end
+			for i,v in ipairs(t2) do
+				array[v] = true;
+			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
+		for v in pairs(array) do
+			table.insert(t1, v);
+		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));