XPost: comp.theory, comp.lang.c++, comp.lang.c
From: polcott333@gmail.com
On 11/4/2025 7:20 PM, Mike Terry wrote:
>
> I don't really see that PO has declined recently - It seems to me he's
> been the way he is for as long as I recall. I would say he's become
> markedly ruder of late, though! Maybe that's all related to his LLMs
> pandering to his delusions and giving him a renewed confidence.
>
>
> Mike.
>
>
news://news.eternal-september.org/20251103195844.661@kylheku.com
On 11/3/2025 10:28 PM, Kaz Kylheku wrote:
>
> How about this minimal viable H:
>
> #include // C interpreter's own API
>
> bool H(fptr P)
> {
> interp *s = interp_init(P);
>
> for (int i = 0; i < 3; i++) {
> if (interp_step(s))
> return true;
> }
>
> return false;
> }
>
> H initializes an interpreter for its argument P.
> Then it applies a very simple abort logic: it
> steps the interpreter state three times. If
> during those three steps, P terminates, it returns
> true. Otherwise it assumes P is nonterminating and
> returns false.
>
> (Pretend that more complicated abort criteria are there.)
>
> The interpreter API consists of primitives built
> into the system, so it isn't traced.
>
> So then we have D:
>
> void D(void)
> {
> if (H(D)) { for (;;); }
> return;
> }
>
> Let's trace H(D). We indicate the simulation levels from 0,
> step numbers from 1 within each level, with a bit of indentation
> to tell apart the levels:
>
*This is the part that Kaz does not understand*
i == 0 reaches if (interp_step(s))
i == 1 reaches if (interp_step(s))
i == 2 reaches if (interp_step(s))
i == 3 NEVER reaches if (interp_step(s))
The whole point is that D simulated by H
cannot possbly reach its own simulated
"return" statement no matter what H does.
If we continue the simulation with the exact
same machine state then H simply returns false
because i == 3.
--
Copyright 2025 Olcott "Talent hits a target no one else can hit; Genius
hits a target no one else can see." Arthur Schopenhauer
--- SoupGate-Win32 v1.05
* Origin: you cannot sedate... all the things you hate (1:229/2)
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