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From: Mild Shock <janburse@fastmail.fm>
Newsgroups: comp.lang.prolog
Subject: Is Rust the culprit? (Was: What about the Holy Grail?)
Date: Mon, 22 Jul 2024 22:16:07 +0200
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Maybe Scryer Prolog is a failure, because Rust
is a failure. Building Scryer Prolog on my machine,
after a git pull of a small change, did just

take this much time:

$ time cargo build --release
[...]
real    6m52.663s
user    7m39.043s
sys     0m3.241s

What did Rust do? And this tabling test case,
2000 shuttle, hangs:

/* Scryer Prolog 0.9.4-107 */
?- use_module(library(tabling)).
    true.
?- [user].
:- table c/1.
c(X) :- c(Y), 0 =< Y, Y < 20000, X is -Y-1.
c(X) :- c(Y), -20000 < Y, Y =< 0, X is -Y+1.
c(0).

?- time(c(_)).
%%% hangs ? %%%

It is solved in a blink in SWI-Prolog:

/* SWI-Prolog 9.3.8 */
?- time(c(_)).
% 540,077 inferences, 0.047 CPU in 0.051 seconds (92% CPU, 11521643 Lips)
true .

The test case is from here:

https://github.com/JanWielemaker/tabling_benchmarks/tree/master