SWI-Prolog - show long list

Question

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?

Solution 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.

Solution 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.

Solution 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

Solution 4

If you want that SWI-Prolog will show the whole list by default you can add this line to your init file:

:- set_prolog_flag(answer_write_options,[max_depth(0)]).

You can modify the init file easily from the GUI (Settings => User init file).

Solution 5

?- 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.

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