1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
|
using System;
using System.Collections.Generic;
using System.Text;
namespace System.Data.Linq.SqlClient {
/// <summary>
/// Walk a tree and return the set of unique aliases it consumes.
/// </summary>
class SqlGatherConsumedAliases {
internal static HashSet<SqlAlias> Gather(SqlNode node) {
Gatherer g = new Gatherer();
g.Visit(node);
return g.Consumed;
}
private class Gatherer : SqlVisitor {
internal HashSet<SqlAlias> Consumed = new HashSet<SqlAlias>();
internal void VisitAliasConsumed(SqlAlias a) {
Consumed.Add(a);
}
internal override SqlExpression VisitColumn(SqlColumn col) {
VisitAliasConsumed(col.Alias);
VisitExpression(col.Expression);
return col;
}
internal override SqlExpression VisitColumnRef(SqlColumnRef cref) {
VisitAliasConsumed(cref.Column.Alias);
return cref;
}
}
}
}
|
