cvc5/examples/api/java/Sequences.java

/******************************************************************************
 * Top contributors (to current version):
 *   Andres Noetzli, Aina Niemetz, Tianyi Liang
 *
 * This file is part of the cvc5 project.
 *
 * Copyright (c) 2009-2021 by the authors listed in the file AUTHORS
 * in the top-level source directory and their institutional affiliations.
 * All rights reserved.  See the file COPYING in the top-level source
 * directory for licensing information.
 * ****************************************************************************
 *
 * A simple demonstration of reasoning about sequences with cvc5 via C++ API.
 */

import static cvc5.Kind.*;

import cvc5.*;

public class Sequences
{
  public static void main(String args[]) throws CVC5ApiException
  {
    Solver slv = new Solver();

    // Set the logic
    slv.setLogic("QF_SLIA");
    // Produce models
    slv.setOption("produce-models", "true");
    // The option strings-exp is needed
    slv.setOption("strings-exp", "true");
    // Set output language to SMTLIB2
    slv.setOption("output-language", "smt2");

    // Sequence sort
    Sort intSeq = slv.mkSequenceSort(slv.getIntegerSort());

    // Sequence variables
    Term x = slv.mkConst(intSeq, "x");
    Term y = slv.mkConst(intSeq, "y");

    // Empty sequence
    Term empty = slv.mkEmptySequence(slv.getIntegerSort());
    // Sequence concatenation: x.y.empty
    Term concat = slv.mkTerm(SEQ_CONCAT, x, y, empty);
    // Sequence length: |x.y.empty|
    Term concat_len = slv.mkTerm(SEQ_LENGTH, concat);
    // |x.y.empty| > 1
    Term formula1 = slv.mkTerm(GT, concat_len, slv.mkInteger(1));
    // Sequence unit: seq(1)
    Term unit = slv.mkTerm(SEQ_UNIT, slv.mkInteger(1));
    // x = seq(1)
    Term formula2 = slv.mkTerm(EQUAL, x, unit);

    // Make a query
    Term q = slv.mkTerm(AND, formula1, formula2);

    // check sat
    Result result = slv.checkSatAssuming(q);
    System.out.println("cvc5 reports: " + q + " is " + result + ".");

    if (result.isSat())
    {
      System.out.println("  x = " + slv.getValue(x));
      System.out.println("  y = " + slv.getValue(y));
    }
  }
}