examples/api/sequences.cpp

   1 /*********************                                                        */
   2 /*! \file sequences.cpp
   3  ** \verbatim
   4  ** Top contributors (to current version):
   5  **   Andres Noetzli
   6  ** This file is part of the CVC4 project.
   7  ** Copyright (c) 2009-2020 by the authors listed in the file AUTHORS
   8  ** in the top-level source directory) and their institutional affiliations.
   9  ** All rights reserved.  See the file COPYING in the top-level source
  10  ** directory for licensing information.\endverbatim
  11  **
  12  ** \brief Reasoning about sequences with CVC4 via C++ API.
  13  **
  14  ** A simple demonstration of reasoning about sequences with CVC4 via C++ API.
  15  **/
  16
  17 #include <cvc4/api/cvc4cpp.h>
  18
  19 #include <iostream>
  20
  21 using namespace CVC4::api;
  22
  23 int main()
  24 {
  25   Solver slv;
  26
  27   // Set the logic
  28   slv.setLogic("QF_SLIA");
  29   // Produce models
  30   slv.setOption("produce-models", "true");
  31   // The option strings-exp is needed
  32   slv.setOption("strings-exp", "true");
  33   // Set output language to SMTLIB2
  34   slv.setOption("output-language", "smt2");
  35
  36   // Sequence sort
  37   Sort intSeq = slv.mkSequenceSort(slv.getIntegerSort());
  38
  39   // Sequence variables
  40   Term x = slv.mkConst(intSeq, "x");
  41   Term y = slv.mkConst(intSeq, "y");
  42
  43   // Empty sequence
  44   Term empty = slv.mkEmptySequence(slv.getIntegerSort());
  45   // Sequence concatenation: x.y.empty
  46   Term concat = slv.mkTerm(SEQ_CONCAT, x, y, empty);
  47   // Sequence length: |x.y.empty|
  48   Term concat_len = slv.mkTerm(SEQ_LENGTH, concat);
  49   // |x.y.empty| > 1
  50   Term formula1 = slv.mkTerm(GT, concat_len, slv.mkReal(1));
  51   // Sequence unit: seq(1)
  52   Term unit = slv.mkTerm(SEQ_UNIT, slv.mkReal(1));
  53   // x = seq(1)
  54   Term formula2 = slv.mkTerm(EQUAL, x, unit);
  55
  56   // Make a query
  57   Term q = slv.mkTerm(AND, formula1, formula2);
  58
  59   // check sat
  60   Result result = slv.checkSatAssuming(q);
  61   std::cout << "CVC4 reports: " << q << " is " << result << "." << std::endl;
  62
  63   if (result.isSat())
  64   {
  65     std::cout << "  x = " << slv.getValue(x) << std::endl;
  66     std::cout << "  y = " << slv.getValue(y) << std::endl;
  67   }
  68 }