Retrospective legislation in Contract Law?

the law that will apply is when the cause of action arose i.e. when the contract was made it has got nothing to do with the time of legal action. for e.g. if u are suing for breach of contract then ur cause of action is the making of the contract and its breach. cause of action are those facts which u have to prove before the courts in order to get remedy. also one has to go through the new law and check whether the retrospective effect was given or not. some transitional provisions are given which one has to go through . check out that too