PROLOG, meaning of

Question

I don't understand what is the meaning of

[sopio|...], [...|...]|...

in the result of ?- findall([X,Y], indirectowner(X, Y), L).:

L = [[sopio, badri], [temur, badri], [temur, leila], [badri, anuki], [badri, tamar], [tamar, ioseb], [sopio, anuki], [sopio|...], [...|...]|...].

I have dafined following facts:

owner(sopio,badri).
owner(temur,badri).
owner(temur,leila).
owner(badri,anuki).
owner(badri,tamar).
owner(tamar,ioseb).

and clauses:

indirectowner(X,Z) :-
owner(X,Z).
indirectowner(X,Z) :-
owner(X,Y), owner(Y,Z).

You might want to have a look at [SWI Prolog show long list](https://stackoverflow.com/questions/8231762/swi-prolog-show-long-list) — lurker, Jun 05 '18 at 20:45

user27815 · Accepted Answer · 2018-06-05T20:25:46.920

3

The answer is abbreviated in order to avoid having too much output on the screen. In SWI-Prolog you can press w after the query to write the whole answer but for your query you need YOURquery ; true. because it is deterministic and for the w to be accepted it needs a non-deterministic query. You can also change the behaviour using Prolog flags.

edited Jun 05 '18 at 20:25

answered Jun 05 '18 at 20:20

user27815

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3

Better: `; false.`! – mat Jun 05 '18 at 20:49
why is that better? – 3va Jun 05 '18 at 21:06
2

Because it does not make a query that otherwise fails succeed! In other words, it does not increase the set of solutions. A shorter version: `;0=1.` – mat Jun 05 '18 at 21:19

PROLOG, meaning of

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