protected override BoundExpression RewriteUnaryExpression(BoundUnaryExpression expression)
{
if (expression.Operand.Type != NodeType.UnaryExpression)
{
return(base.RewriteUnaryExpression(expression));
}
var subUnary = (BoundUnaryExpression)expression.Operand;
bool isIdentity =
(expression.Op.OperatorType == UnaryOperatorType.Identity && subUnary.Op.OperatorType == UnaryOperatorType.Identity) ||
(expression.Op.OperatorType == UnaryOperatorType.Negation && subUnary.Op.OperatorType == UnaryOperatorType.Negation) ||
(expression.Op.OperatorType == UnaryOperatorType.LogicalNot && subUnary.Op.OperatorType == UnaryOperatorType.LogicalNot);
bool isNegation =
(expression.Op.OperatorType == UnaryOperatorType.Identity && subUnary.Op.OperatorType == UnaryOperatorType.Negation) ||
(expression.Op.OperatorType == UnaryOperatorType.Negation && subUnary.Op.OperatorType == UnaryOperatorType.Identity);
if (isIdentity)
{
return(RewriteExpression(subUnary.Operand));
}
if (isNegation)
{
return(RewriteExpression(new BoundUnaryExpression(UnaryOperator.Bind("-", subUnary.Op.OperandType), subUnary.Operand)));
}
return(base.RewriteUnaryExpression(expression));
}
private BoundExpression Negate(BoundExpression condition)
{
if (condition is BoundLiteral literal)
{
var value = (bool)literal.Value;
return(new BoundLiteral(!value));
}
var op = UnaryOperator.Bind("!", ValueTypeSymbol.Boolean);
return(new BoundUnaryExpression(op, condition));
}