prolog

问题 you can use =.. to convert simple terms. ?- x(a,b,c) =.. A. A = [x, a, b, c]. what about complex terms : x(a,b(c,d)) ==> [x,a,[b,c,d]] x(a,b(c,q(d))) ==> [x,a,[b,c,[q,d]]] then as separate task i want to re-generate the terms with changed functor : x(a,b(c,d)) ==> [x,a,[b,c,d]] ==> y(a,f(c,d)) 回答1: deep_univ(X, Y) :- X =.. [H|Rest], ( Rest = [] -> Y = X ; maplist(deep_univ, Rest, ExpRest), Y=[H|ExpRest] ). rev_univ([H|Rest], Y) :- maplist(rev_univ, Rest, RestT), Y =.. [H|RestT]. rev_univ(H, H

问题 you can use =.. to convert simple terms. ?- x(a,b,c) =.. A. A = [x, a, b, c]. what about complex terms : x(a,b(c,d)) ==> [x,a,[b,c,d]] x(a,b(c,q(d))) ==> [x,a,[b,c,[q,d]]] then as separate task i want to re-generate the terms with changed functor : x(a,b(c,d)) ==> [x,a,[b,c,d]] ==> y(a,f(c,d)) 回答1: deep_univ(X, Y) :- X =.. [H|Rest], ( Rest = [] -> Y = X ; maplist(deep_univ, Rest, ExpRest), Y=[H|ExpRest] ). rev_univ([H|Rest], Y) :- maplist(rev_univ, Rest, RestT), Y =.. [H|RestT]. rev_univ(H, H

问题 David Tonhofer posed an interesting problem about occurs check. An occurs check aware coroutine can be realized as follows with a predicate with_occurs_check/2 which can be easily implemented as a refinement of with_occurs_check/1: occurs_check_aware_freeze(X, G) :- current_prolog_flag(F), freeze(X, with_occurs_check(F, G)). Namely by using an with_occurs_check/2 with a further parameter. But the main problem of a realiable with_occurs_check/[1,2] that also works with backtracking remains.

问题 This question is directly related to first order logic creating terms for arithmetic expressions using prolog. After implementing the logic as per the link I have issues with the formatting of the ourput for printauth/1 . It currently results as 8-2+4* -3 , how is it possible to get something like ((8-2)+(4* -3)) (notice its not the same as +(-(8,2),*(4,-3))) . I have been trying to using various options (\k,\q) in format/2 predicate but nothing works. even I tried write_canonical and other

问题 I want to restrict the query property(X, use, Y) to values of Y in the list [a,b,c] . c/1 is true for only those values of Y . I thought the following would work, but it doesn't. c(a). c(b). c(c). property(X, use, Y). c(Y). The following statements yield only false . person(1). property(1, use, _). I'm using Problog, but I'm not using any Problog functions here, so I think I am misunderstanding something about unification. I thought c(Y) would generate the list and Y would be unified across

问题 I am attempting to write a predicate for the following task. Write a predicate distances(Bs, B, Ds) where Bs and Ds are lists of variables such that the ith element of the Ds is the absolute difference between the variable B and the ith element of Bs know this is incorrect but it what I believe I roughly should be trying to do distances([],_,[]). distances([H|T],B,A) :-abs(H - B,A),distances(T,B,A) Do I need to return the result of the abs predicate into the recusive call to distance? I can

问题 I am learning Prolog these days and need to combine two list into one that follows this rule: ListA: [], ListB: [] => ResultList: [] ListA: [], ListB:[a,b,c] => ResultList: [[a],[b],[c]] ListA: [1,2], ListB:[a,b,c] => ResultList: [[1,2,a],[1,2,b],[1,2,c]] I am stuck with a recursive function output value problem and here is my coding: extend_my_path([],_,_,_). extend_my_path([H|T],OriginalPath,OrignailMewPaths,NewPaths) :- append(OriginalPath,[H],NewPath), append(OrignailMewPaths,[NewPath]

问题 I am learning Prolog these days and need to combine two list into one that follows this rule: ListA: [], ListB: [] => ResultList: [] ListA: [], ListB:[a,b,c] => ResultList: [[a],[b],[c]] ListA: [1,2], ListB:[a,b,c] => ResultList: [[1,2,a],[1,2,b],[1,2,c]] I am stuck with a recursive function output value problem and here is my coding: extend_my_path([],_,_,_). extend_my_path([H|T],OriginalPath,OrignailMewPaths,NewPaths) :- append(OriginalPath,[H],NewPath), append(OrignailMewPaths,[NewPath]

问题 I am learning Prolog these days and need to combine two list into one that follows this rule: ListA: [], ListB: [] => ResultList: [] ListA: [], ListB:[a,b,c] => ResultList: [[a],[b],[c]] ListA: [1,2], ListB:[a,b,c] => ResultList: [[1,2,a],[1,2,b],[1,2,c]] I am stuck with a recursive function output value problem and here is my coding: extend_my_path([],_,_,_). extend_my_path([H|T],OriginalPath,OrignailMewPaths,NewPaths) :- append(OriginalPath,[H],NewPath), append(OrignailMewPaths,[NewPath]

问题 [a,a,a,a,b,c,c,a,a,d,e,e,e,e] => [[4,a],b,[2,c],[2,a],d,[4,e]]. please help me solve this problem I have this code, but I do not know how to bring it to the one that is required or how can it be done differently or easier: p([]):- !. p( [X] ):- !, write(X). p( [X | T] ):-!, write(X), write(", "), p(T). first_letter([H], Let, Num, Mid, Res):- ( H = Let, New_num is Num +1, G = [Let], Prom = [New_num | G], Res = [Prom | Mid], ! ; true ), ( H \= Let,New_num is 1, G = [Let], Prom = [Num | G], New