I came across this code, which I assume will be faster than iterating one element at a time. nth0_det(0, [Elem|_], Elem) :- !. nth0_det(1, [_,Elem|_], Elem) :- !. nth0_det(2, [_,_,Elem|_], Elem) :- !. nth0_det(3, [_,_,_,Elem|_], Elem) :- !. nth0_det(4, [_,_,_,_,Elem|_], Elem) :- !. nth0_det(5, [_,_…

This is just a pure guest ( WAG ) but sometimes they are correct. Obviously such generators could could go on until memory is exhausted. So the ISO standard for Prolog set the limit on the number of arguments for such predicates. I don’t think 6 is the limit because lambdas use 7. I tried to find th…

OK I see what you are asking now. (For others the question was edited) I agree that the limit for augments does not apply for list AFAIK, so the decision AFAIK was arbitrarily made by the creator of the code. However in many programming languages, such limits are common and even defined in the st…

In https://www.swi-prolog.org/pldoc/man?section=deep-indexing , there is Currently, the depth of indexing is limited to 7 levels. A list of length more than 6 is essentially a term of depth more than 6, is this why the loop is unrolled only 6 times?

Nth0/3 implementaion in swi-prolog

Discussion

rajashekar November 29, 2020, 1:39pm 3

I do not understand how the limit on number of parameters will apply in this situation.

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Nth0/3 implementaion in swi-prolog

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