1 /* 2 * Copyright (C) 2018 The Android Open Source Project 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 #ifndef LIBTEXTCLASSIFIER_UTILS_GRAMMAR_SEMANTICS_EVALUATORS_CONSTITUENT_EVAL_H_ 18 #define LIBTEXTCLASSIFIER_UTILS_GRAMMAR_SEMANTICS_EVALUATORS_CONSTITUENT_EVAL_H_ 19 20 #include "utils/base/arena.h" 21 #include "utils/grammar/semantics/eval-context.h" 22 #include "utils/grammar/semantics/evaluator.h" 23 #include "utils/grammar/semantics/expression_generated.h" 24 #include "utils/grammar/semantics/value.h" 25 26 namespace libtextclassifier3::grammar { 27 28 // Returns the semantic value of an evaluated constituent. 29 class ConstituentEvaluator : public SemanticExpressionEvaluator { 30 public: Apply(const EvalContext & context,const SemanticExpression * expression,UnsafeArena *)31 StatusOr<const SemanticValue*> Apply(const EvalContext& context, 32 const SemanticExpression* expression, 33 UnsafeArena*) const override { 34 TC3_DCHECK_EQ(expression->expression_type(), 35 SemanticExpression_::Expression_ConstituentExpression); 36 const ConstituentExpression* constituent_expression = 37 expression->expression_as_ConstituentExpression(); 38 const auto constituent_it = 39 context.rule_constituents.find(constituent_expression->id()); 40 if (constituent_it != context.rule_constituents.end()) { 41 return constituent_it->second; 42 } 43 // The constituent was not present in the rule parse tree, return a 44 // null value for it. 45 return nullptr; 46 } 47 }; 48 49 } // namespace libtextclassifier3::grammar 50 51 #endif // LIBTEXTCLASSIFIER_UTILS_GRAMMAR_SEMANTICS_EVALUATORS_CONSTITUENT_EVAL_H_ 52