public AI.IFunApp And(AI.IExpr p, AI.IExpr q)
{
Expression e1 = Converter.Unbox <Expression>(p);
Expression e2 = Converter.Unbox <Expression>(q);
return(Converter.Box(encoder.CompoundExpressionFor(ExpressionType.Bool, ExpressionOperator.And, e1, e2), decoder));
}
public override Expression Convert <Expression>(IExpressionEncoder <Variable, Expression> encoder)
{
return(encoder.CompoundExpressionFor(ExpressionType.Int32,
ExpressionOperator.Addition,
encoder.VariableFor(var),
encoder.ConstantFor(value)));
}
/// <summary>
/// Construct left - right, or left iff right == 0
/// </summary>
public static Expression SmartSubtraction <Variable, Expression>(this IExpressionEncoder <Variable, Expression> encoder,
Expression left, Expression right, IExpressionDecoder <Variable, Expression> decoder)
{
Contract.Requires(decoder != null);
Contract.Requires(encoder != null);
int value;
if (decoder.IsConstantInt(right, out value) && value == 0)
{
return(left);
}
return(encoder.CompoundExpressionFor(ExpressionType.Int32, ExpressionOperator.Subtraction, left, right));
}
/// <summary>
/// Perform some rewritings to the boxed expressions, so that is is simplified, and it is nicer for a human reader
/// </summary>
public static BoxedExpression MakeItPrettier <Variable>(this BoxedExpression be, IExpressionDecoder <BoxedVariable <Variable>, BoxedExpression> decoder, IExpressionEncoder <BoxedVariable <Variable>, BoxedExpression> encoder)
{
Contract.Requires(encoder != null);
var result = be;
// 0. Do not do any work on MinValue <= exp, as -exp <= -MinValue is wrong
BinaryOperator bop;
BoxedExpression left, right;
int maybeMinInt; long maybeMinLong;
if (be.IsBinaryExpression(out bop, out left, out right) &&
(bop == BinaryOperator.Cle || bop == BinaryOperator.Clt || bop == BinaryOperator.Cle_Un || bop == BinaryOperator.Clt_Un) &&
((left.IsConstantInt(out maybeMinInt) && maybeMinInt == Int32.MinValue) || (left.IsConstantInt64(out maybeMinLong) && maybeMinLong == Int64.MinValue))
)
{
return(result);
}
// 1. If it is a polynomial, do some arithmetic simplification, puts all the variables on one side, etc.
Polynomial <BoxedVariable <Variable>, BoxedExpression> pol;
if (Polynomial <BoxedVariable <Variable>, BoxedExpression> .TryToPolynomialForm(be, decoder, out pol))
{
if (pol.IsTautology)
{
return(encoder.ConstantFor(true));
}
// m1 - m2 == 0 becomes m1 == m2
BoxedVariable <Variable> x, y;
Rational k;
if (pol.TryMatch_XMinusYEqualk3(out x, out y, out k) && k.IsZero)
{
var xExp = encoder.VariableFor(x);
var yExp = encoder.VariableFor(y);
return(encoder.CompoundExpressionFor(ExpressionType.Bool, ExpressionOperator.Equal, xExp, yExp));
}
result = pol.ToPureExpression(encoder);
}
// To do: add some more pretty printing there
result = MakeItPrettier(result, x => encoder.ConstantFor(x));
return(result);
}
public void Assign(Expression x, Expression exp, INumericalAbstractDomainQuery <Variable, Expression> preState)
{
embedded = UnderlyingPolyhedra.Constrain(embedded, Converter.Box(encoder.CompoundExpressionFor(ExpressionType.Bool, ExpressionOperator.Equal, x, exp), decoder));
}
