[Haskell-cafe] GHC 7.0.1 developer challenges

John D. Ramsdell ramsdell0 at gmail.com
Wed Dec 15 01:13:52 CET 2010

On Tue, Dec 14, 2010 at 1:48 PM, Peter Simons <simons at cryp.to> wrote:
> I beg your pardon? I didn't say anything about "32M". I said that
> designing software to rely on a GHC-enforced memory limit as a means of
> "dealing" with infinite loops feels really not like a particularly good
> solution.

Sorry about that. I think the previous responder was asserting the 32M
limit, not you.

The program I wrote analyzes cryptographic protocols.  It is
theoretically impossible to decide if there is a finite number of
answers to every protocol question that can be posed within our
framework.  Thus, I cannot guarantee termination.

What I can and do, is allow users to set a step count bound, after
which the program aborts.  But guess what users do.  They keep
increasing the step count  bound to see if just a few more steps will
allow termination on their problem.  Of course, some end up setting
the bound so high, that thrashing occurs.  So for implementations of
undecidable algorithms, you really need an intelligent memory bound on
the GHC runtime.


More information about the Haskell-Cafe mailing list