A while back I saw an example contract which allowed users to send any ERC-20 tokens through one of its functions, but I can't seem to find anything about this anywhere anymore. So, what is the simplest way to implement:
a) A function in a smart contract that allows the contract to handle transactions between another (specific) token contract?
b) A function allowing for any ERC-20 token to be used (probably through the user specifying the token contract)?
Thanks.