Just Scryer or for any ISO Prolog?

[hurufu]

First of all thanks for trying to implement a long awaited package manager for Prolog.

In many places it is written explicitly that pkg.pl is for Scryer Prolog. Have you considered other Prologs? I think all of them can benefit from common package system. If there are some compatibility problems we can write for example small translation layer that will slightly massage module text to get accepted by the widest variety of Prologs.

[constraintAutomaton]

I’d say yes, but how to do it is still an open question. Right now¹, I think @bakaq is working on making it compatible with Trealla Prolog in #15. There’s also some relevant discussion happening here. Issue #24 is also related to this issue. You are very welcome if you have some insight about how to do it ☺️. I think also this thread is more vaguely related to the question.

Footnotes

1. We're still working with a fairly minimal implementation. ↩

[constraintAutomaton]

Oh, this thread too is related to it.

[bakaq]

See previous discussion about this at #1, in specific my thought process in #1 (comment).

Basically, I think reimplementing LogTalk is too much work for a first thing, and a pure ISO (without system specific functionality like modules or dif/2) wouldn't be too useful for the things I want to do. My main goal is to allow an ecosystem to form around library(reif) and library(clpz), as that is the greatest impact, and for this it suffices to support Scryer Prolog and similar systems (like Trealla, which I think already works with this package manager and I'll put it into the CI soon).

We are thinking about wider compatibility somewhat, but I don't think it should be a priority at this point. Currently the things we depend that go beyond the original ISO 13211-1 are DCGs (comming in 13211-3), a Quintus-style module system, term expansion, dif/2, shell/2, some file handling predicates, predicates for dealing with environment variables, and either ignoring unknown modules or having them at the same place as Scryer. These features seem to be mostly widely available or easy to shim, but GNU Prolog doesn't have modules for example.

This project is meant to just be an experiment for now, and it's public domain so eventually the relevant parts could be reused for a more general or more official package manager even if I completely lose interest.

[triska]

As of June 2025, DCGs are part of the Prolog standard via ISO/IEC TS 13211-3:2025!