/// <summary>
///
/// </summary>
/// <param name="select"></param>
/// <param name="column"></param>
/// <returns></returns>
public static SelectExpression RemoveColumn(this SelectExpression select, ColumnDeclaration column)
{
List <ColumnDeclaration> columns = new List <ColumnDeclaration>(select.Columns);
columns.Remove(column);
return(select.SetColumns(columns));
}
/// <summary>
///
/// </summary>
/// <param name="columns"></param>
/// <returns></returns>
protected virtual ReadOnlyCollection <ColumnDeclaration> VisitColumnDeclarations(ReadOnlyCollection <ColumnDeclaration> columns)
{
List <ColumnDeclaration> alternate = null;
for (int i = 0, n = columns.Count; i < n; i++)
{
ColumnDeclaration column = columns[i];
Expression e = this.Visit(column.Expression);
if (alternate == null && e != column.Expression)
{
alternate = columns.Take(i).ToList();
}
if (alternate != null)
{
alternate.Add(new ColumnDeclaration(column.Name, e));
}
}
if (alternate != null)
{
return(alternate.AsReadOnly());
}
return(columns);
}
/// <summary>
///
/// </summary>
/// <param name="a"></param>
/// <param name="b"></param>
/// <returns></returns>
protected virtual bool CompareColumnDeclaration(ColumnDeclaration a, ColumnDeclaration b)
{
return(a.Name == b.Name && this.Compare(a.Expression, b.Expression));
}