Generators and short hand syntax

[0xbb]

Hello!
I would like to use ASP generator rules to model a problem in dlvhex2.
But I couldn't find anything about that in the documentation.

Is there a way to use generator rules with dlvhex2?

I made a mini example modeled after my requirements:

Facts:

% pair(ID, VALUE).
pair(1, 1). pair(2, 1). pair(2, 3). pair(3, 2).

id(X) :- pair(X,_).

I want to be able to write:

% all ids only having values smaller 2
all_values_smaller_2(ID) :- id(ID),
                            X <= 2: pair(ID, X).

Instead of:

exp(ID) :- pair(ID, X), X > 2.
all_values_smaller_2(ID):- not exp(ID), id(ID).

Is this possible with dlvhex2?

---

Additionally it also would be nice to have the Gringo short hand syntax available:

id(1..3).
pair(1,1; 2,1; 2,3; 3,2).

Greetings,
Bruno

[credl]

Dear Bruno!

Conditional literals are supported, but currently only for ordinary atoms
and not for builtin predicates. Therefore you can write your program as
follows:

% pair(ID, VALUE).
pair(1, 1). pair(2, 1). pair(2, 3). pair(3, 2).

id(X) :- pair(X,).
set2(X) :- pair(,X), X <= 2.

% all ids only having values smaller 2
all_values_smaller_2(ID) :- id(ID),
set2(X) : pair(ID, X).

Thanks for suggesting improvements!

Best regareds,
Christoph

2015-06-22 13:42 GMT+02:00 Bruno Bierbaumer [email protected]:

Hello!
I would like to use ASP generator rules to model a problem in dlvhex2.
But I couldn't find anything about that in the documentation.

Is there a way to use generator rules with dlvhex2?

I made a mini example modeled after my requirements:
Facts:

% pair(ID, VALUE).
pair(1, 1). pair(2, 1). pair(2, 3). pair(3, 2).

id(X) :- pair(X,_).

I want to be able to write:

% all ids only having values smaller 2
all_values_smaller_2(ID) :- id(ID),
X <= 2: pair(ID, X).

Instead of:

exp(ID) :- pair(ID, X), X > 2.
all_values_smaller_2(ID):- not exp(ID), id(ID).

Is this possible with dlvhex2?

Additionally it also would be nice to have the Gringo short hand syntax
available:

id(1..3).
pair(1,1; 2,1; 2,3; 3,2).

Greetings,
Bruno

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[0xbb]

Hi Christoph!
Thanks for your amazingly fast answer :)!
I think this is actually solving my problem.

Greetings,
Bruno