I agree with Joel. I think someone brought this up earlier as well. Most OP_EVAL transactions won't be complex enough to require more than a few loops.
--Zell ------------------------ "It stopped being just a website a long time ago. For many of us, most of us, Wikipedia has become an indispensable part of our daily lives." — Jimmy Wales, Founder of Wikipedia Help protect it now. Please make a donation today: http://www.wikimediafoundation.org/wiki/Donate --- On Sat, 12/31/11, Joel Joonatan Kaartinen <joel.kaarti...@gmail.com> wrote: > From: Joel Joonatan Kaartinen <joel.kaarti...@gmail.com> > Subject: Re: [Bitcoin-development] Alternative to OP_EVAL > To: rocon...@theorem.ca > Cc: bitcoin-development@lists.sourceforge.net > Date: Saturday, December 31, 2011, 4:54 AM > Wouldn't it work to restrict the > number of executions of OP_EVAL allowed > per transaction? That way it wouldn't allow for unlimited > looping. If > there's too many OP_EVAL executions during the transaction > evaluation, > just consider the transaction illegal. 3 would be enough > for the > purposes people have been planning for here I think. > > - Joel > > On Thu, 2011-12-29 at 11:42 -0500, rocon...@theorem.ca > wrote: > > On Thu, 29 Dec 2011, theymos wrote: > > > > > On Thu, Dec 29, 2011, at 01:55 AM, rocon...@theorem.ca > wrote: > > >> The number of operations executed is still > bounded by the number of > > >> operations occurring in the script. > With the OP_EVAL proposal the > > >> script language becomes essentially Turing > complete, with only an > > >> artificial limit on recursion depth > preventing arbitrary computation > > >> and there is no way to know what code will > run without executing it. > > > > > > Even if OP_EVAL allowed infinite depth, you'd > still need to explicitly > > > specify all operations performed, since there is > no way of looping. > > > > That's not true. Gavin himself showed how to use > OP_EVAL to loop: > > OP_PUSHDATA {OP_DUP OP_EVAL} OP_DUP OP_EVAL. > > > > Basically OP_DUP lets you duplicate the code on the > stack and that is the > > key to looping. I'm pretty sure from here we get > get Turing completeness. > > Using the stack operations I expect you can implement > the SK-calculus > > given an OP_EVAL that allows arbitrary depth. > > > > OP_EVAL adds dangerously expressive power to the > scripting language. > > > > > > ------------------------------------------------------------------------------ > Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't > need a complex > infrastructure or vast IT resources to deliver seamless, > secure access to > virtual desktops. With this all-in-one solution, easily > deploy virtual > desktops for less than the cost of PCs and save 60% on VDI > infrastructure > costs. Try it free! http://p.sf.net/sfu/Citrix-VDIinabox > _______________________________________________ > Bitcoin-development mailing list > Bitcoin-development@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/bitcoin-development > ------------------------------------------------------------------------------ Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex infrastructure or vast IT resources to deliver seamless, secure access to virtual desktops. With this all-in-one solution, easily deploy virtual desktops for less than the cost of PCs and save 60% on VDI infrastructure costs. Try it free! http://p.sf.net/sfu/Citrix-VDIinabox _______________________________________________ Bitcoin-development mailing list Bitcoin-development@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bitcoin-development
