The pack `reif` couldn't be installed due to a 404 and seems now removed

As I mentioned in the irc channel, I seem to recall having a reif package which was failing with a 404,
and now:

?- pack_install(reif).
% Contacting server at ... done
Warning: No registered pack matches "reif"

are the ideas implemented in (indexing dif/2) implemented elsewhere?
A few days ago I wrote to prof Tom Schrijvers, which was listed as the maintainer, and he answered that unfortunately he didn’t have much free time to maintain it, but we are free to adopt it.

Could that be hosted directly on the swi website?

I don’t think it’s a SWI-Prolog “pack”. You can get it directly from here:
which is linked from here:

(Putting this into a “pack” is on my ever-growing “to-do” list …)


Yes indeed @peter.ludemann, this topic was the equivalent of “it would be very nice to have that as a pack”. It’s also useful for newcomers that read the metalevel tutorial - which hugely emphasizes that library - to not be confused by the non-existence of the pack.

I was planning on putting the source file on github, then creating a pack. It’s not a lot of work, but I just hadn’t got around to doing it …

Should the repo be put under a particular organization in github? Like,
I can also do it if you give me the above details, having just read

No. Packs are in principle not hosted under the SWI-Prolog organization. They are community contributions and maintained outside the core system.

1 Like

I’ll add reif to my github repository … I’ve already done that for pack(edcg) when the previous maintainer archived the code. Please give me a few days.


Sorry for the delay, as I needed this on my laptop too, I went ahead and created the repo at

It shows up automatically at so I’ll mark this as solved :slight_smile: