Learn Ethereum smart contract programming

Post by justusw » Mon, Jul 24, 2017, 10:11 AM UTC

halflings wrote: post #25

omarforgotpwd wrote: post #16

Programmable smart contracts are a great idea in a world where programmers write bug free code. That world does not exist yet. Until we have near-perfect code writing AIs every new smart contract is just a disaster waiting to happen.

That's like saying legal contracts are a disaster because we do not live in an ideal world where lawyers don't do mistakes, and there are no legal loopholes. Granted, bugs are much more common than legal loopholes, but in the same way an operating system's APIs and constraints are tested until it becomes reliable enough for other people to rely on it, I can see some standard types of contracts (in the same way as in…

Post by ym705 » Mon, Jul 24, 2017, 10:16 AM UTC

hexhex wrote: post #33

I didn't have high expectations for Solidity considering the recent vulnerabilities, but even these were disappointed. If some guy writes this kind of code at home, alright, but this as the alleged foundation for our future financial system? Frightening. Just one example: "Our function EndLottery() must be only accessible by the owner of the lottery." [0] function EndLottery() public { if (msg.sender == owner) { ...…

Post by ym705 » Mon, Jul 24, 2017, 10:18 AM UTC

jsnathan wrote: post #29

ym705 wrote: post #20

Earlier quoted context omitted.

Could you explain more how would it be possible?

In the example code used, the random number which determines the winner is derived from the previous block hash. Since the lottery-owner determines when the function is run, they could call the function when the previous block hash favors their own bet, or else modify their bet before calling the function.

Post by staticelf » Mon, Jul 24, 2017, 10:19 AM UTC

mbrock wrote: post #30

staticelf wrote: post #17

The problem I see with Ethereum is that it is way too complex. I have read perhaps at least 10 times on their home page without even understanding what it does, what problems it solves etc. This is the sole reason why I don't think it will be successful in it's current state. With most successful tech or services or whatever the core idea is often super simple to grasp and you can instantly see the benefit. I don't s…

You know Bitcoin is useful. One of the useful things in Bitcoin is that you can make a transaction conditional on a multiparty approval ("multisig"). This is used by many organizations to control funds in a safe way. Ethereum lets you construct even more interesting types of transactions. For example you can easily implement the logic of a crowdfunding (unless X is raised by time Y everyone is refunded). In that cont…

Post by ym705 » Mon, Jul 24, 2017, 10:22 AM UTC

staticelf wrote: post #38

mbrock wrote: post #30

Earlier quoted context omitted.

You know Bitcoin is useful. One of the useful things in Bitcoin is that you can make a transaction conditional on a multiparty approval ("multisig"). This is used by many organizations to control funds in a safe way. Ethereum lets you construct even more interesting types of transactions. For example you can easily implement the logic of a crowdfunding (unless X is raised by time Y everyone is refunded). In that cont…

Ok but that raises a lot of technical questions. Do I myself host that logic or is the logic itself distributed? While creating a crowdfunding contract, I am the host in my mind so assuming that the smart contract is hosted on my machines this must mean that when people are sending Ethereum to my wallet the logic does it's thing? Another version of that could be that the logic is sent out to all interested peers and…