Re: interactive use, the overwhelming norm ?

Hi Patrick,

On 2014-02-16 06:11, Patrick wrote:
> Is there a simple example that takes a database file, a query file and
> writes the results to a 3rd file?

one way is to define a "main" predicate (doesn't have to be called
"main") and call it from the command line, like this:

dbfile.pl
---------
a(2).
a(3).

queryfile.pl
------------
main :-
  forall(a(X), (write(X), nl)),
  close(Stream),
  halt.

From the command line, call:
swipl -g main dbfile.pl queryfile.pl > resultsfile.txt

resultsfile.txt
---------------
2
3

You can also create an executable, see:
http://www.swi-prolog.org/FAQ/PrologScript.txt
http://www.swi-prolog.org/pldoc/man?section=compilation#sec:2.10.2.4

Hope this helps,
Kilian