[Theory] Halting problem

[Norbert Nemec]

On 10/10/10 19:36, %u wrote:
> == Quote from Norbert Nemec (Norbert at Nemec-online.de)'s article
>> In language design, the theoretical halting problem actually is often an
>> argument because the compiler does not know the memory limitation at run
>> time. The finite memory of the machine can therefore not be used to
>> reason about a piece of code. For the purpose of the compiler, the
>> machine has to be assumed to have arbitrarily much (i.e. infinite) memory.
> I don't know people in language design, but I suspect they know their stuff and I
> would be surprised to hear that they would think of the theoretical Halting
> problem where the practical halting problem as an argument would suffice. Programs
> generally can't index an infinite amount of memory.
> Why would they use an argument which rests on an abstract system where they could
> just as easily use an argument based on an actual system.

Basically: because 1GB=infinity for all purposes of logical reasoning.

> Anyway, I made this thread because in uni I got the Halting problem explained in
> totally the wrong context and would like other people not to make the same wrong
> first step.

I know that situation very well: having the big Aha-effect after years 
of misunderstanding calls for telling people about it. Actually, I find 
it quite interesting to discuss this kind of issues once in a while.