Scasp expected behaviour

Help!
1

Hi all,

I have currently got the following which I don’t understand.

I’m using: scasp on swish.

My code looks like this:

https://swish.swi-prolog.org/p/scasp_error.pl

% s(CASP) Programming
:- use_module(library(scasp)).

% Your program goes here

false :-q,r(1).

q.
r(2).
r(1).

thing:-q,r(1).

p(X):- X #>2.

/** <examples> Your example queries go here, e.g.
?- ? q.
?- ? r(1).
?- ? thing.
?- ? p(X).
*/

I try the following queries:

?- ? q.
false
?- ? r(1).
false
?- ? thing.
s(CASP) model
q holds
thing holds
r holds for 1
?- ? p(X).
scasp_just_html:clpq/5: Deterministic procedure scasp_swish:to_html/3 failed

But I expected :

?- ? thing.
false.

?- ? p(X).
X#>2.
2

That is not your fault :slight_smile: Both now work as you expected them. Constraints of the binding are printed in native clp(q) notation. I’m not sure that can be avoided in SWISH.

Thanks for reporting!

3

Using the link provided by Sam https://swish.swi-prolog.org/p/scasp_error.pl

% s(CASP) Programming
:- use_module(library(scasp)).

% Your program goes here

false :-q,r(1).

q.
r(2).
r(1).

thing:-q,r(1).

p(X):- X #>2.

for thing. the result is true. Sam was expecting false.

Just noting in case someone wants a sanity check on what someone else sees.

Current results I see

?- q.
false

?- r(1).
false

?- thing.
true

?- p(X).
procedure `A #> B' does not exist
Reachable from:
	  p(A)

EDIT

As Jan W. notes below I did not use ? with the query. I know if I am making this mistake so are others.

Here is the right way.

image

4

You need to run ? thing. to get sCASP semantics. Otherwise you have Prolog semantics.

1 Like
5

Thanks again Jan.
I also at first missed the ? syntax, maybe try and make that more clear in the example scasp page with first a call to scasp/1 then the same call with the short hand ? explicitly pointed out.

6

Good point. Done. Note that you can save the notebook as a normal user notebook, edit it and send me the link :slight_smile:

1 Like