Quote from: AlexGR on March 15, 2016, 11:06:35 AM

Quote from: TPTB_need_war on March 15, 2016, 10:43:11 AM

The primary reason that smart contracts are basically useless, is because a block chain can't form a consensus about anything external, except for signatures transactions that are authorized by public key cryptography to modify block chain state.

I'm sure they have some not very widespread uses but the "virtual computer" concept is definitely useless, so far.

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It can only form a consensus about block chain state transformation with the clock period being blocks and the longest chain rule.

Still, if the clock period is block, and, code-wise, can be used as a ...clock, then there is a clock.

So, say, I write a program which says "I add 42 to 42 to 42 to 42 ...until next block is found".

No you can't. Programs can only look at blocks in the past, not the future and there is no "until a block is found" operation. More practically if there were, a program that tried to do a long-running loop like that would likely run out of gas (which results in state rollback and loss of gas). Programs have to be small and simple.