examples/SimpleVC.php

   1 #! /usr/bin/php
   2 ##! \file SimpleVC.php
   3 ### \verbatim
   4 ### Original author: mdeters
   5 ### Major contributors: none
   6 ### Minor contributors (to current version): none
   7 ### This file is part of the CVC4 prototype.
   8 ### Copyright (c) 2009, 2010, 2011  The Analysis of Computer Systems Group (ACSys)
   9 ### Courant Institute of Mathematical Sciences
  10 ### New York University
  11 ### See the file COPYING in the top-level source directory for licensing
  12 ### information.\endverbatim
  13 ###
  14 ### \brief A simple demonstration of the PHP interface
  15 ###
  16 ### A simple demonstration of the PHP interface.  Compare to the
  17 ### C++ interface in simple_vc_cxx.cpp; they are quite similar.
  18 ###
  19 ### To run, use something like:
  20 ###
  21 ###   ln -s ../builds/src/bindings/php/.libs/CVC4.so CVC4.so
  22 ###   ln -s ../builds/src/bindings/php/CVC4.php CVC4.php
  23 ###   ./SimpleVC.php
  24 ####
  25
  26 use strict;
  27 use CVC4;
  28
  29 my $em = new CVC4::ExprManager();
  30 my $smt = new CVC4::SmtEngine($em);
  31
  32 # Prove that for integers x and y:
  33 #   x > 0 AND y > 0  =>  2x + y >= 3
  34
  35 my $integer = $em->integerType();
  36
  37 my $x = $em->mkVar("x", $integer);
  38 my $y = $em->mkVar("y", $integer);
  39 my $zero = $em->mkConst(new CVC4::Integer(0));
  40
  41 my $x_positive = $em->mkExpr($CVC4::GT, $x, $zero);
  42 my $y_positive = $em->mkExpr($CVC4::GT, $y, $zero);
  43
  44 my $two = $em->mkConst(new CVC4::Integer(2));
  45 my $twox = $em->mkExpr($CVC4::MULT, $two, $x);
  46 my $twox_plus_y = $em->mkExpr($CVC4::PLUS, $twox, $y);
  47
  48 my $three = $em->mkConst(new CVC4::Integer(3));
  49 my $twox_plus_y_geq_3 = $em->mkExpr($CVC4::GEQ, $twox_plus_y, $three);
  50
  51 my $formula = new CVC4::Expr($em->mkExpr($CVC4::AND, $x_positive, $y_positive))->impExpr(new CVC4::Expr($twox_plus_y_geq_3));
  52
  53 print "Checking validity of formula " . $formula->toString() . " with CVC4.\n";
  54 print "CVC4 should report VALID.\n";
  55 print "Result from CVC4 is: " . $smt->query($formula)->toString() . "\n";
  56