74 lines
2.4 KiB
C++
74 lines
2.4 KiB
C++
/* -*- C++ -*-
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* Serene programming language.
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*
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* Copyright (c) 2019-2021 Sameer Rahmani <lxsameer@gnu.org>
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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#ifndef SERENE_ENVIRONMENT_H
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#define SERENE_ENVIRONMENT_H
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#include "serene/llvm/patches.h"
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#include <llvm/ADT/DenseMap.h>
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#include <mlir/Support/LogicalResult.h>
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namespace serene {
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/// This class represents a classic lisp environment (or scope) that holds the
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/// bindings from type `K` to type `V`. For example an environment of symbols
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/// to expressions would be `Environment<Symbol, Node>`
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template <typename K, typename V>
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class Environment {
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Environment<K, V> *parent;
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// The actual bindings storage
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llvm::DenseMap<K, V> pairs;
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public:
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Environment() : parent(nullptr) {}
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Environment(Environment *parent) : parent(parent){};
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/// Look up the given `key` in the environment and return it.
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llvm::Optional<V> lookup(K key) {
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if (auto value = pairs.lookup(key)) {
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return value;
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}
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if (parent) {
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return parent->lookup(key);
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}
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return llvm::None;
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};
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/// Insert the given `key` with the given `value` into the storage. This
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/// operation will shadow an aleady exist `key` in the parent environment
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mlir::LogicalResult insert_symbol(K key, V value) {
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pairs.insert(std::pair<K, V>(key, value));
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return mlir::success();
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};
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};
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} // namespace serene
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#endif
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