prolog

问题 I am trying to write a function in Scheme and Prolog that returns first, middle and last item of a list. E.g., find([4,5,8,7,9],L), L = [4,8,9] . I came up with this piece of code for Scheme language, but I am new to Prolog and don't know much, so how I can get the same result in Prolog? (define (frst L) (car L)) (define (last L) (if (null? (cdr L)) (car L) (last (cdr L)))) (define (nth L x) (if (= x 1) (car L) (nth (cdr L) (- x 1)))) (define (firstMidLast L) (list (frst L) (nth L (ceiling (/

问题 I am currently trying to understand the basics of prolog. I have a knowledge base like this: p(a). p(X) :- p(X). If I enter the query p(b) , the unification with the fact fails and the rule p(X) :- p(X) is used which leads the unification with the fact to fail again. Why is the rule applied over and over again after that? Couldn't prolog return false at this point? After a certain time I get the message "Time limit exceeded". I'm not quite sure why prolog uses the rule over and over again,

问题 I am currently trying to understand the basics of prolog. I have a knowledge base like this: p(a). p(X) :- p(X). If I enter the query p(b) , the unification with the fact fails and the rule p(X) :- p(X) is used which leads the unification with the fact to fail again. Why is the rule applied over and over again after that? Couldn't prolog return false at this point? After a certain time I get the message "Time limit exceeded". I'm not quite sure why prolog uses the rule over and over again,

问题 I have 2 lists with random number of elemets. Eg A=[1,2,4,5] and B=[1,2,3]. Result should be 2. Code that I tried: domains Numbers1 = integer* Numbers2 = integer* int_list=integer* predicates nondeterm prinadl(integer, int_list) clauses //here going the code that read number that I've entered, and according to entered numer,programm should do something answer(T):- T=5, P = 0, write ("Enter the 1st list"), readterm (int_list, L), write ("Enter the 2nd list"), readterm (int_list, L2), L2 = [H|V

问题 I have 2 lists with random number of elemets. Eg A=[1,2,4,5] and B=[1,2,3]. Result should be 2. Code that I tried: domains Numbers1 = integer* Numbers2 = integer* int_list=integer* predicates nondeterm prinadl(integer, int_list) clauses //here going the code that read number that I've entered, and according to entered numer,programm should do something answer(T):- T=5, P = 0, write ("Enter the 1st list"), readterm (int_list, L), write ("Enter the 2nd list"), readterm (int_list, L2), L2 = [H|V

问题 So basically it seems that GNU Prolog use 28bit integer on my 32bit x86 Linux. The code below can not be compiled: foo(A) :- A0 is 0xdeadbeef, A1 is A0 >> 8, A2 is A0 >> 16, A3 is A0 >> 24. Then I am confused with two typical situations below: How to represent a 32bit integer in GNU Prolog (like 0xdeadbeef)? and pushing it further, how to represent a 64 bit integer ? On 64 bit x86 Linux, long long type in C has 64 bit. When using GNU Prolog to call C, the interface defined in the manual has

问题 So basically it seems that GNU Prolog use 28bit integer on my 32bit x86 Linux. The code below can not be compiled: foo(A) :- A0 is 0xdeadbeef, A1 is A0 >> 8, A2 is A0 >> 16, A3 is A0 >> 24. Then I am confused with two typical situations below: How to represent a 32bit integer in GNU Prolog (like 0xdeadbeef)? and pushing it further, how to represent a 64 bit integer ? On 64 bit x86 Linux, long long type in C has 64 bit. When using GNU Prolog to call C, the interface defined in the manual has

问题 So basically it seems that GNU Prolog use 28bit integer on my 32bit x86 Linux. The code below can not be compiled: foo(A) :- A0 is 0xdeadbeef, A1 is A0 >> 8, A2 is A0 >> 16, A3 is A0 >> 24. Then I am confused with two typical situations below: How to represent a 32bit integer in GNU Prolog (like 0xdeadbeef)? and pushing it further, how to represent a 64 bit integer ? On 64 bit x86 Linux, long long type in C has 64 bit. When using GNU Prolog to call C, the interface defined in the manual has

问题 I am using AllegroGraph 4. I have a triple store, and I am trying to add new triples only if they don't already exist. Here is my Prolog query: (select (?news) (alfas ?news) (a-- ?news !tst:has-annotation !tst:Test))) where alfas checks for a condition(it works fine) and a-- is defined like this: (<-- (a-- ?s ?p ?o) ;; Fails unless all parts ground. (lisp (not (triple-exists-p ?s ?p ?o))) (lisp (add-triple ?s ?p ?o))) I have also tried defining it like this: (<-- (a-- ?s ?p ?o) ;; Fails

问题 I am using AllegroGraph 4. I have a triple store, and I am trying to add new triples only if they don't already exist. Here is my Prolog query: (select (?news) (alfas ?news) (a-- ?news !tst:has-annotation !tst:Test))) where alfas checks for a condition(it works fine) and a-- is defined like this: (<-- (a-- ?s ?p ?o) ;; Fails unless all parts ground. (lisp (not (triple-exists-p ?s ?p ?o))) (lisp (add-triple ?s ?p ?o))) I have also tried defining it like this: (<-- (a-- ?s ?p ?o) ;; Fails