问题
I'm using SWI-Prolog and I'm trying to print a list but if the list has more than 9 items - it look like that -
[1, 15, 8, 22, 5, 19, 12, 25, 3|...]
is there a way to show the whole list?
回答1:
Have a look at: http://www.swi-prolog.org/FAQ/AllOutput.html
The simple solution is to type w after the answer is given, i.e.:
?- n_queens_problem(10,X).
X = [1, 3, 6, 8, 10, 5, 9, 2, 4|...] [write]
X = [1, 3, 6, 8, 10, 5, 9, 2, 4, 7]
After you have pressed the "w"-key "[write]" is displayed at the end and the full solution appears in the next line.
回答2:
I've found two ways.
1.
?- set_prolog_flag(answer_write_options,[max_depth(0)]).
true.
Then do your command that is printing a truncated list.
(set_prolog_flag documentation)
2.
?- atom_chars(goodbye_prolog, X) ; true.
(AllOutput documentation)
Put ; true. at the end of the call that results in a long list. Then push the w key on your keyboard. The result is:
?- sudoku([_,_,2,3,_,_,_,_,_,_,_,_,3,4,_,_], Solution); true.
Solution = [4, 1, 2, 3, 2, 3, 4, 1, 1|...] [write]
Solution = [4, 1, 2, 3, 2, 3, 4, 1, 1, 2, 3, 4, 3, 4, 1, 2] ;
true.
回答3:
If prolog returns only one answer, you can make it wait by typing "; true." after the predicate. Then, if you press "w", you will get to see the whole list as written in the doc : http://www.swi-prolog.org/FAQ/AllOutput.html
回答4:
?- createListSomehow(List), print(List), nl.
will do it neatly enough. That's what I do.
Variation:
?- use_module(library(pprint)). %load a library to do pretty-printing
?- createListSomehow(List), print_term(List,[]), nl.
The [] argument to print_term is an (empty) list of options. For more information, see documentation.
来源：https://stackoverflow.com/questions/8231762/swi-prolog-show-long-list