/// <summary>
/// Updates the is null.
/// </summary>
/// <param name="isnull">The isnull.</param>
/// <param name="expression">The expression.</param>
/// <returns></returns>
protected IsNullExpression UpdateIsNull(IsNullExpression isnull, Expression expression)
{
if (expression != isnull.Expression)
{
return(new IsNullExpression(expression));
}
return(isnull);
}
/// <summary>
/// Compares the is null.
/// </summary>
/// <param name="a">A.</param>
/// <param name="b">The b.</param>
/// <returns></returns>
protected virtual bool CompareIsNull(IsNullExpression a, IsNullExpression b)
{
return(this.Compare(a.Expression, b.Expression));
}
/// <summary>
/// Visits the is null.
/// </summary>
/// <param name="isnull">The isnull.</param>
/// <returns></returns>
protected virtual Expression VisitIsNull(IsNullExpression isnull)
{
var expr = this.Visit(isnull.Expression);
return(this.UpdateIsNull(isnull, expr));
}