public static SelectExpression RemoveField(this SelectExpression select, FieldDeclaration field)
{
var fields = new List <FieldDeclaration>(select.Fields);
fields.Remove(field);
return(select.SetFields(fields));
}
public static SelectExpression AddField(this SelectExpression select, FieldDeclaration field)
{
var fields = new List <FieldDeclaration>(select.Fields)
{
field
};
return(select.SetFields(fields));
}
protected override Expression VisitSelect(SelectExpression select)
{
select = (SelectExpression)base.VisitSelect(select);
var fields = select.Fields.OrderBy(f => f.Name).ToList();
var removed = new BitArray(fields.Count);
var anyRemoved = false;
for (int i = 0, n = fields.Count; i < n; i++)
{
var fi = fields[i];
var fxi = new FieldExpression(fi.Expression, select.Alias, fi.Name);
for (int j = i + 1; j < n; j++)
{
if (!removed.Get(i))
{
FieldDeclaration fj = fields[j];
if (AreSameExpression(fi.Expression, fj.Expression))
{
var fxj = new FieldExpression(fj.Expression, select.Alias, fj.Name);
_map.Add(fxj, fxi);
removed.Set(j, true);
anyRemoved = true;
}
}
}
}
if (anyRemoved)
{
var newFields = new List<FieldDeclaration>();
for (int i = 0, n = fields.Count; i < n; i++)
{
if (!removed.Get(i))
newFields.Add(fields[i]);
}
select = select.SetFields(newFields);
}
return select;
}
