gistfile1.lua

--
-- Let you write code like
-- 		chain(func1):next(func2):next(func3):go()
--
function chain(cb)
	local queue = {}

	local n, go;
	go = function()
		local cb = table.remove(queue, 1)
		if cb then cb(go) end
	end

	n = {
		next = function(a1, a2)
			local cb = a2 or a1
			table.insert(queue, cb)
			return {
				next = n.next,
				go = go
			}
		end,
		go = go
	}
	return n.next(cb)
end

--
-- Example
--
local c = chain(function(done)
	print('X')
	done()
end):next(function(done)
	print('Y')
	done()
end):next(function(done)
	print('Z')
	done()
end):go()