Potassco Files

Release notes gringo 4.0
------------------------

These notes provide some hints on the language of the new gringo series 4.  A
full documentation of the language will be provided in the future.

A good starting point is the ASPCore 2 language specification (gringo-4 should
support everything but queries) at

    https://www.mat.unical.it/aspcomp2013/ASPStandardization

Furthermore, you find ASPCore 2 encodings along with problem descriptions in
the benchmark suite of the ASP Competition 2013 at

    https://www.mat.unical.it/aspcomp2013/OfficialProblemSuite

Note that Version 4.0 still lacks support for an embedded scripting language
and some options like for example reification (--reify). Call gringo with
option --help to get an overview what is supported.

Please direct all questions, bug reports, and feature requests through the
support facilities at http://sourceforge.net/p/potassco/wiki/Home

- http://sourceforge.net/mailarchive/forum.php?forum_name=potassco-users
- http://sourceforge.net/p/potassco/bugs
- http://sourceforge.net/p/potassco/feature-requests

Finally, here is a collection of small example programs, which highlight
similarities and differences between gringo-3 and gringo-4, and show some
features beyond the ASPCore 2 language.

Ground Terms:
  gringo-3 and gringo-4:
    p(1). p(2). p(3).
    p(a). p(b). p(c).
    p(#infimum).
    p(#supremum).
    p("hello world!").
    p(f(1,g(2))).
    p(|20+2*-3|/2\3).
  gringo-4:
    p(#inf).
    p(#sup).

Definitions:
  gringo-3 and gringo-4:
    #const a = 1.
    #const b = a + a.
	p(b).
  gringo-3:
    p(a).
    #const a = 1.
  gringo-4:
    p(a).
    #const a = 1.

Range Terms:
  gringo-3 and gringo-4:
    p(1..10).

Normal Rules:
  gringo-3 and gringo-4:
    q(1,2). q(2,3).
    r(2,3). r(3,4).
    s(4).
    p(X) :- q(X,Y), r(Y,Z), not s(Z).
  gringo-4:
    q(1,2). q(2,3).
    r(2,3). r(3,4).
    s(4).
    p(X) :- q(X,Y); r(Y,Z); not s(Z).

Pooling:
  gringo-3 and gringo-4:
    p(a;b;c).
  gringo-3:
    p(a,b;c).
  gringo-4:
    p(a,b;c).

Projection:
  gringo-3 and gringo-4:
    p(1,2). p(1,3).
    q(X) :- p(X,_).
  gringo-4:
    p(1) :- not q(1).
    q(1) :- not p(1).
    r :- not p(_).

Extended Safety:
  gringo-4:
    p(10).
    q(X) :- p(X-1).
    r(X) :- p(X+1).
    s(X) :- p(X*2).
    t(X) :- p(2*(X-1)).

Counting Literals:
  Head:
    gringo-3:
      p(1..3).
      1 { q(X,Y): p(X): p(Y): X < Y, q(X,X): p(X) }.
    gringo-4:
      p(1..3).
      1 { q(X,Y): p(X), p(Y), X < Y; q(X,X): p(X) }.
    gringo-4:
      { p(1..3) }.
      1 { q(X,Y): p(X), p(Y), X < Y; q(X,X): p(X) }.
    gringo-4:
      2 != { p(1..3) } <= 2.
  Body:
    gringo-3:
      p(1..3).
      { q(X,Y): p(X): p(Y) }.
      q :- 1 { q(X,Y): p(X): p(Y): X < Y, q(X,X): p(X) }.
    gringo-4:
      p(1..3).
      { q(X,Y): p(X), p(Y) }.
      q :- 1 { q(X,Y): p(X), p(Y), X < Y; q(X,X): p(X) }.
    gringo-4:
      { p(1..3) }.
      { q(X,Y): p(X), p(Y) }.
      q :- 1 { q(X,Y): p(X), p(Y), X < Y; q(X,X): p(X) }.

Aggregates:
  Head:
    gringo-3:
      p(1..3). q(2..4).
      #sum [ r(X)=X: p(X): q(X) ] 1.
    gringo-4:
      p(1..3). q(2..4).
      #sum { X,r: r(X): p(X), q(X) } 1.
  Body:
    gringo-3:
      p(1..3). q(2..4).
      { r(X): p(X), r(X): q(X) }.
      s :- #sum { r(X)=X: p(X): q(X) } 1.
    gringo-4:
      p(1..3). q(2..4).
      { r(X): p(X); r(X): q(X) }.
      s :- #sum { X,r: r(X), p(X), q(X) } 1.
  Assignments:
    gringo-3:
      p(1..3).
      q(X) :- X = [ p(Y)=Y ].
    gringo-4:
      p(1..3).
      q(X) :- X = #sum { Y: p(Y) }.
  Supported Functions:
    #min, #max, #sum, #sum+, #count
    
Conditional Literals:
  Head:
    gringo-3:
      p(1..3). q(2..4).
      r(X): p(X): q(X) | a.
    gringo-4:
      p(1..3). q(2..4).
      r(X): p(X), q(X); a.
    gringo-4:
      p(1..3). q(2..4).
      r(X): p(X), q(X) | a.
    gringo-4:
      { p(1..3); q(2..4) }.
      r(X): p(X), q(X); a.
  Body:
    gringo-3:
      p(1..3). q(2..4). a.
      { r(X): p(X), r(X): q(X) }.
      s :- r(X): p(X): q(X), a.
    gringo-4:
      p(1..3). q(2..4). a.
      { r(X): p(X); r(X): q(X) }.
      s :- r(X): p(X), q(X); a.
    gringo-4:
      { p(1..3); q(2..4); a}.
      { r(X): p(X); r(X): q(X) }.
      s :- r(X): p(X), q(X); a.

Optimization:
  gringo-3:
    p(1..6).
    q(2..7).
    a.
    3 { r(X): p(X), r(X): q(X) }.
    #minimize [ r(X)=X@1: p(X): q(X), a=2@3 ].
  gringo-4:
    p(1..6).
    q(2..7).
    a.
    3 { r(X): p(X); r(X): q(X) }.
    #minimize { X@1,r: r(X), p(X), q(X); 2@3: a }.
  gringo-4:
    p(1..6).
    q(2..7).
    a.
    3 { r(X): p(X); r(X): q(X) }.
    #maximize { -X@1,r: r(X), p(X), q(X); -2@3: a }.
  gringo-4:
    p(1..6).
    q(2..7).
    a.
    3 { r(X): p(X); r(X): q(X) }.
    :~ r(X), p(X), q(X). [X@1,r]
    :~ a. [2@3]

Display Statements:
  Predicate:
    gringo-3:
      #hide.
      #show a/0.
      a. b.
    gringo-4:
      #show a/0.
      a. b.
  Term:
    gringo-4:
      #show a.
      #show 1+2.
    gringo-4:
      #show.
      #show q(X): p(X), X!=2, 2 { p(Z) }.
      { p(1..3) }.

Include Files:
  gringo-3 and gringo-4:
    #include "file.lp".

PS: Roland never said the examples would make any sense.