Hi Sean

Thanks for answering my post and so quickly.

Sorry to drag down the list with this....

Here is an example.

I wrote in caps between the code

I found a simple database file on the web that called solar.pl

Here is what I typed to use it:

gprolog

GNU Prolog 1.4.4 (64 bits)
Compiled Nov  6 2013, 22:31:52 with gcc
By Daniel Diaz
Copyright (C) 1999-2013 Daniel Diaz

| ?- consult(solar) .
compiling /pat/prolog/solar.pl for byte code...
/pat/prolog/solar.pl compiled, 22 lines read - 1356 bytes written, 6 ms

(1 ms) yes
| ?- listing
.

% file: /pat/prolog/solar.pl

head :-
    body.

orbits(mercury, sun).
orbits(venus, sun).
orbits(earth, sun).
orbits(mars, sun).
orbits(moon, earth).
orbits(phobos, mars).
orbits(deimos, mars).

planet(A) :-
    orbits(A, sun).

satellite(A) :-
    orbits(A, B),
    planet(B).
satellite(moon).

yes
| ?-


NOW IF I TYPE:

orbits(mercury, sun) .

I GET:

yes

IF I TYPE:

| ?- orbits(mybutt, sun) .

no


ALL LOGICAL BUT IF I TYPE :

| ?- sally(tall) .
uncaught exception: error(existence_error(procedure,sally/1),top_level/0)
| ?-

I am not sure how I could add new facts without putting them in a separate file. I am wondering if the dynamic directive has something to do with this but I am still very shaky and was wondering if there was simple example of this.

Thanks again-Patrick







On 11/19/2013 11:27 AM, emacstheviking wrote:
Patrick,

To list the database use the "listing" predicate:
ftp://gprolog.univ-paris1.fr/pub/gprolog/manual/html_node/gprolog047.html#listing%2F1

It takes a parameter which you can use to narrow down what is listed as well. That should help you see what's in your database.

To make a query, just type it in at the prompt and hit RETURN... sounds obvious but that's all there is to ity unless I misunderstood your question!

Perhaps you'd care to post all or some (if it is large) of your facts and things that you have and then say what you want to query?

Sean.



On 19 November 2013 16:22, Patrick <[email protected] <mailto:[email protected]>> wrote:

    Hi Everyone

    Sorry to ask this....

    I am studying and making progress but I can't figure out the
    simplest thing.

    I have been able to consult little database files and query but I
    don't know how to list facts and query against them in the same file.

    Could someone post a little example?

    Sorry to bother everyone with this stupidity.

    -Patrick



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