OmniSciDB  1dac507f6e
 All Classes Namespaces Files Functions Variables Typedefs Enumerations Enumerator Friends Macros Pages
UsedColumnsVisitor.h
Go to the documentation of this file.
1 /*
2  * Copyright 2019 OmniSci, Inc.
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #include "ScalarExprVisitor.h"
18 
19 #include <unordered_set>
20 
21 class UsedColumnsVisitor : public ScalarExprVisitor<std::unordered_set<int>> {
22  protected:
23  std::unordered_set<int> visitColumnVar(
24  const Analyzer::ColumnVar* column) const override {
25  return {column->get_column_id()};
26  }
27 
28  std::unordered_set<int> aggregateResult(
29  const std::unordered_set<int>& aggregate,
30  const std::unordered_set<int>& next_result) const override {
31  auto result = aggregate;
32  result.insert(next_result.begin(), next_result.end());
33  return result;
34  }
35 };
std::unordered_set< int > visitColumnVar(const Analyzer::ColumnVar *column) const override
std::unordered_set< int > aggregateResult(const std::unordered_set< int > &aggregate, const std::unordered_set< int > &next_result) const override
int get_column_id() const
Definition: Analyzer.h:195