public override VfpExpression Visit(VfpIsEmptyExpression expression)
{
Write(" NOT EXISTS (");
expression.Argument.Accept(this);
Write(")");
return(expression);
}
private static bool GetInnerProjectionExpression(VfpProjectExpression expression, out VfpProjectExpression innerProjectionExpression, out bool hasNotExpression)
{
innerProjectionExpression = null;
hasNotExpression = false;
if (!expression.Input.VariableName.StartsWith("SingleRowTable"))
{
return(false);
}
var newInstanceExpression = expression.Projection as VfpNewInstanceExpression;
if (newInstanceExpression == null)
{
return(false);
}
var notExpression = newInstanceExpression.Arguments[0] as VfpNotExpression;
VfpIsEmptyExpression isEmptyExpression = null;
if (notExpression == null)
{
isEmptyExpression = newInstanceExpression.Arguments[0] as VfpIsEmptyExpression;
}
else
{
isEmptyExpression = notExpression.Argument as VfpIsEmptyExpression;
hasNotExpression = true;
}
if (isEmptyExpression == null)
{
return(false);
}
innerProjectionExpression = isEmptyExpression.Argument as VfpProjectExpression;
return(innerProjectionExpression != null);
}
public virtual VfpExpression Visit(VfpIsEmptyExpression expression)
{
return(new VfpIsEmptyExpression(expression.ResultType, expression.Argument.Accept(this)));
}
