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From: Mild Shock <janburse@fastmail.fm>
Newsgroups: comp.lang.prolog
Subject: Is there room to adopt a flag strict_iso?
Date: Tue, 24 Jun 2025 18:00:28 +0200
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 > **iso_strict** is ISO-conforming strict mode, providing
 > only ISO features and no implementation specific ones

Maybe a good name would then be "use_strict", instead
of "strict_iso", if a permutation of it is already
used in the form "iso_strict" by ECLiPSe Prolog.
"use_strict" would be motivated from JavaScript:

 > JavaScript's strict mode is a way to *opt in* to a
restricted variant of JavaScript, thereby implicitly
opting-out of "sloppy mode". Strict mode isn't just a subset:
it *intentionally* has different semantics from normal
code. Strict mode code and non-strict mode code can
coexist, so scripts can opt into strict mode incrementally.

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Strict_mode

In JavaScript the mode is local. You can place the
"use_strict" directive inside any function you want, and
opt in to this function and all sub functions.
So "use_strict=on" would mean ISO conforming.

This would solve the problem that some Prolog systems
have an "iso" flag, but setting it to true does not
imply they become 100% ISO conforming. It rather tells
the system to have the behaviour of some

predicates change to ISO conforming. So the "use_strict"
would be a conformity flag, and not a scope flag. It
would not reduce the scope of a Prolog system or a
Prolog modul to use less built-ins, flags etc..