Trigger functions after a predefined sequence of keys have been pressed (LÖVE)

sequences.lua

------Copyright 2015  Pablo A. Mayobre------
--Licensed under the terms of MIT Lincense--

local seq = {}

local split = function (text,pat)
	local t = {}
	while true do
		local pos1, pos2 = text:find(pat, 1, true)
		if not pos1 then
			t[#t + 1] = text
			return t
		end
		t[#t + 1] = text:sub(1, pos1 - 1)
		text = text:sub(pos2 + 1)
	end
end

local unpack = unpack or table.unpack

seq.new = function (self,f,t)
	local steps = {}

	for k,v in ipairs(split(t, ",")) do
		steps[k] = split(v,"+")
	end

	self.inst[#self.inst + 1] = {
		f = f;
		steps = steps;
		current = 1;
	}
end

seq.update = function (self)
	for k,v in ipairs(self.inst) do
		if love.keyboard.isDown(unpack(v.steps[v.current])) then
			v.current = v.current + 1
		end

		if v.current > #v.steps then
			v.f()
			self.inst[k] = nil
		end
	end
end

return seq

Define a new sequence using sequences:new() as follows:

sequences = require "sequences"

local callback = function ()
    --This is gonna be called when the sequence is matched
end

local sequence = "up,up,down,down,left,right,left,right,b,a" --The Konami code sequence

sequences:new(callback,sequence)

You can also define key combinations that should be pressed at the same time as follows:

local sequence = "ctrl+shift+c" --Code used for console in games like The Sims and such
sequences:new(calback,sequence)

Or a combination of both things

sequence = "up+down,left+right"
sequences:new(callback,sequence)

Remember to call sequences:update() in you love.update callback

love.update = function ()
    sequences:update()
end