There is no need for a BIP draft. "Turing complete" is just a fancy, executive-impressing term for "it can run any computer program", or put even more simply, "it can loop"
Furthermore, the specification of such a language is trivial. It is the economics of validation that is the complex piece. Proving whether or not a program will halt as expected - The Halting Problem - is near impossible for most complex programs. As a result, your proof is... running the program. That produces enormous validation consequences and costs for generic-execution scripts when applied to a decentralized network of validation P2P nodes. If you need that capability, it is just as easy to use a normal C/C++/etc. computer language, with your preferred algorithm libraries and development tools. See https://github.com/jgarzik/moxiebox for a working example of provable execution. On Thu, Dec 10, 2015 at 9:35 AM, Luke Durback via bitcoin-dev < bitcoin-dev@lists.linuxfoundation.org> wrote: > Hello Bitcoin-Dev, > > I hope this isn't out of line, but I joined the mailing list to try to > start a discussion on adding opcodes to make Script Turing Pseudo-Complete > as Wright suggested is possible. > > --- > > In line with Wright's suggestion, I propose adding a return stack > alongside the, already existing, control stack. > > The principle opcodes (excluding conditional versions of call and > return_from) needed are > > OP_DEFINITION_START FunctionName: The code that follows is the definition > of a new function to be named TransactionSenderAddress.FunctionName. If > this function name is already taken, the transaction is marked invalid. > Within the transaction, the function can be called simply as FunctionName. > > OP_DEFINITION_END: This ends a function definition > > OP_FUNCTION_NAME FunctionName: Gives the current transaction the name > FunctionName (this is necessary to build recursive functions) > > --- > > OP_CALL Namespace.FunctionName Value TransactionFee: This marks the > transaction as valid. It also pushes the current execution location onto > the return stack, debits the calling transaction by the TransactionFee and > Value, and creates a new transaction specified by Namespace.FunctionName > with both stacks continued from before (this may be dangerous, but I see no > way around it) with the specified value. > > OP_RETURN_FROM_CALL_AND_CONTINUE: This pops the top value off the return > stack and continues from the specified location with both stacks in tact. > > --- > > It would also be useful if a transaction can create another transaction > arbitrarily, so to prepare for that, I additionally propose > > OP_NAMESPACE: Pushes the current namespace onto the control stack > > This, combined with the ability to make new transactions arbitrarily would > allow a function to pay its creator. > > > > I understand that this isn't all that is needed, but I think it's a > start. I hope this proposal has met you all well, > > Luke Durback > > _______________________________________________ > bitcoin-dev mailing list > bitcoin-dev@lists.linuxfoundation.org > https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev > >
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