Not sure if this a bug but I defined the following: three_pairs(X,Y,Z, R):- X =(,), Y =(,), Z =(,), R = (X,Y,Z). For the query: three_pairs(,,,Result). I got the following with out parenthesis around the last pair: Result = ((, ), (, ), , ). I expected the following: Result = ((, ), (, ),…

[image] vjktm: three_pairs(X,Y,Z, R):- X =(,), Y =(,), Z =(,), R = (X,Y,Z). For the query: three_pairs(,,,Result). I got the following with out parenthesis around the last pair: Result = ((, ), (, ), , ). I expected the following: Result = ((, ), (, ), (, )). However, if I do: three_…

you should use code fences (i.e. three backtick) otherwise your code is pretty unreadable: three_pairs(X,Y,Z, R):- X =(_,_), Y =(_,_), Z =(_,_), R = (X,Y,Z).

OT: you can use the three dots menu and then the Edit Raw icon to get the Prolog code of the question

Sorry, bad cut/paste from SWI-Prolog console.

Thank you everyone for your responses and links to related discussions. I now know a bit more about SWI-Prolog, pairs, comma lists and comma operator. I will name the pairs as it seems to be the recommended solution.

Possibly bad result in console for a triple of pairs

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brebs October 7, 2022, 6:32pm 5

Use a term name, for less confusion - Surprising result with equals dot dot

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Possibly bad result in console for a triple of pairs

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