chore: import upstream snapshot with attribution

paddle/ap/include/axpr/function.h

@@ -0,0 +1,51 @@
+// Copyright (c) 2024 PaddlePaddle Authors. All Rights Reserved.
+//
+// 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.
+
+#pragma once
+
+#include "paddle/ap/include/adt/adt.h"
+#include "paddle/ap/include/axpr/core_expr.h"
+#include "paddle/ap/include/axpr/frame.h"
+#include "paddle/ap/include/axpr/type.h"
+
+namespace ap::axpr {
+
+template <typename SerializableValueT>
+struct FunctionImpl {
+  Lambda<CoreExpr> lambda;
+  std::optional<Frame<SerializableValueT>> global_frame{};
+
+  bool operator==(const FunctionImpl& other) const { return this == &other; }
+
+  adt::Result<int64_t> GetHashValue() const {
+    int64_t hash_value = reinterpret_cast<int64_t>(lambda.shared_ptr().get());
+    if (global_frame.has_value()) {
+      ADT_LET_CONST_REF(global_frame_ptr, global_frame.value().Get());
+      int64_t frame_hash_value = reinterpret_cast<int64_t>(global_frame_ptr);
+      hash_value = adt::hash_combine(hash_value, frame_hash_value);
+    }
+    return hash_value;
+  }
+};
+
+template <typename SerializableValueT>
+ADT_DEFINE_RC(Function, FunctionImpl<SerializableValueT>);
+
+template <typename SerializableValueT>
+struct TypeImpl<Function<SerializableValueT>> : public std::monostate {
+  using std::monostate::monostate;
+  const char* Name() const { return "function"; }
+};
+
+}  // namespace ap::axpr