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On 5/31/2024 2:50 AM, Fred. Zwarts wrote:how can it be that H is pure but correct simulation of H is not pure?Op 31.mei.2024 om 00:01 schreef olcott:*pure function H definitely halts you are confused*On 5/30/2024 4:54 PM, joes wrote:>Am Thu, 30 May 2024 09:55:24 -0500 schrieb olcott:>
>typedef int (*ptr)(); // ptr is pointer to int function in CYeah, of course not, if H doesn’t halt.
00 int H(ptr p, ptr i);
01 int D(ptr p)
02 {
03 int Halt_Status = H(p, p);
04 if (Halt_Status)
05 HERE: goto HERE;
06 return Halt_Status;
07 }
08
09 int main()
10 {
11 H(D,D);
12 return 0;
13 }
>
The left hand-side are line numbers of correct C code.
This code does compile and does conform to c17.
>
Everyone with sufficient knowledge of C can easily determine that D
correctly emulated by any *pure function* H (using an x86 emulator)
cannot possibly reach its own simulated final state at line 06 and halt.
>
To actually understand my words (as in an actual honest dialogue)
you must pay careful attention to every single word. Maybe you
had no idea that *pure functions* must always halt.
>
Or maybe you did not know that every computation that never reaches
its own final state *DOES NOT HALT* even if it stops running because
it is no longer simulated.
Since the claim is that H is also a computation, it holds for H, as well. That means that H *DOES NOT HALT* even if it stops running because it is no longer simulated.
>
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