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/********************* */
/*! \file strings-new.cpp
** \verbatim
** Top contributors (to current version):
** Aina Niemetz
** This file is part of the CVC4 project.
** Copyright (c) 2009-2020 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.\endverbatim
**
** \brief Reasoning about strings with CVC4 via C++ API.
**
** A simple demonstration of reasoning about strings with CVC4 via C++ API.
**/
#include <iostream>
#include <cvc4/api/cvc4cpp.h>
using namespace CVC4::api;
int main()
{
Solver slv;
// Set the logic
slv.setLogic("S");
// 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");
// String type
Sort string = slv.getStringSort();
// std::string
std::string str_ab("ab");
// String constants
Term ab = slv.mkString(str_ab);
Term abc = slv.mkString("abc");
// String variables
Term x = slv.mkConst(string, "x");
Term y = slv.mkConst(string, "y");
Term z = slv.mkConst(string, "z");
// String concatenation: x.ab.y
Term lhs = slv.mkTerm(STRING_CONCAT, x, ab, y);
// String concatenation: abc.z
Term rhs = slv.mkTerm(STRING_CONCAT, abc, z);
// x.ab.y = abc.z
Term formula1 = slv.mkTerm(EQUAL, lhs, rhs);
// Length of y: |y|
Term leny = slv.mkTerm(STRING_LENGTH, y);
// |y| >= 0
Term formula2 = slv.mkTerm(GEQ, leny, slv.mkReal(0));
// Regular expression: (ab[c-e]*f)|g|h
Term r = slv.mkTerm(REGEXP_UNION,
slv.mkTerm(REGEXP_CONCAT,
slv.mkTerm(STRING_TO_REGEXP, slv.mkString("ab")),
slv.mkTerm(REGEXP_STAR,
slv.mkTerm(REGEXP_RANGE, slv.mkString("c"), slv.mkString("e"))),
slv.mkTerm(STRING_TO_REGEXP, slv.mkString("f"))),
slv.mkTerm(STRING_TO_REGEXP, slv.mkString("g")),
slv.mkTerm(STRING_TO_REGEXP, slv.mkString("h")));
// String variables
Term s1 = slv.mkConst(string, "s1");
Term s2 = slv.mkConst(string, "s2");
// String concatenation: s1.s2
Term s = slv.mkTerm(STRING_CONCAT, s1, s2);
// s1.s2 in (ab[c-e]*f)|g|h
Term formula3 = slv.mkTerm(STRING_IN_REGEXP, s, r);
// Make a query
Term q = slv.mkTerm(AND,
formula1,
formula2,
formula3);
// check sat
Result result = slv.checkSatAssuming(q);
std::cout << "CVC4 reports: " << q << " is " << result << "." << std::endl;
if(result.isSat())
{
std::cout << " x = " << slv.getValue(x) << std::endl;
std::cout << " s1.s2 = " << slv.getValue(s) << std::endl;
}
}
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