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/*
* Copyright (C) 2018 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "utils/grammar/parsing/derivation.h"
#include <algorithm>
#include <vector>
namespace libtextclassifier3::grammar {
bool Derivation::IsValid() const {
bool result = true;
Traverse(parse_tree, [&result](const ParseTree* node) {
if (node->type != ParseTree::Type::kAssertion) {
// Only validation if all checks so far passed.
return result;
}
// Positive assertions are by definition fulfilled,
// fail if the assertion is negative.
if (static_cast<const AssertionNode*>(node)->negative) {
result = false;
}
return result;
});
return result;
}
std::vector<Derivation> ValidDeduplicatedDerivations(
const std::vector<Derivation>& derivations) {
std::vector<Derivation> result;
for (const Derivation& derivation :
DeduplicateDerivations<Derivation>(derivations)) {
// Check that asserts are fulfilled.
if (derivation.IsValid()) {
result.push_back(derivation);
}
}
return result;
}
} // namespace libtextclassifier3::grammar