token_standard.fi

struct TokenData(
	string name,
	string symbol,
	nat decimals
);
struct PassthroughData(
	address from,
	mutez amount,
	bytes contractData
);

storage bmap[address=>mutez] balances;
storage TokenData data;

entry transfer(address to, mutez amount, ?bytes contractData){
  assert(storage.balances.in(SENDER));
  let mutez bal = storage.balances.get(SENDER);
  assert(bal >= input.amount);
  storage.balances.push(SENDER, sub(bal, input.amount));
  
  bal = mutez 0;
  if (storage.balances.in(input.to)){
    bal = storage.balances.get(input.to);
  }
  storage.balances.push(input.to, add(bal, input.amount));
	
  if (isset(input.contractData)){
    transfer(input.to, mutez 0, new PassthroughData(SENDER, input.amount, to_some(input.contractData)));
  }
}