129 lines
3.2 KiB
C++
129 lines
3.2 KiB
C++
/* Symbol definitions.
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Copyright (C) 2025 Free Software Foundation, Inc.
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GCC is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3, or (at your option)
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any later version.
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GCC is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GCC; see the file COPYING3. If not see
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<http://www.gnu.org/licenses/>. */
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#pragma once
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#include <cstdint>
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#include <unordered_map>
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#include <string>
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#include <memory>
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namespace elna
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{
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namespace boot
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{
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/**
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* Symbol table.
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*/
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template<typename T, T nothing>
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class symbol_table
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{
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public:
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using symbol_ptr = T;
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using iterator = typename std::unordered_map<std::string, symbol_ptr>::iterator;
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using const_iterator = typename std::unordered_map<std::string, symbol_ptr>::const_iterator;
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private:
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std::unordered_map<std::string, symbol_ptr> entries;
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std::shared_ptr<symbol_table> outer_scope;
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public:
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/**
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* Constructs a new symbol with an optional outer scope.
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*
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* \param scope Outer scope.
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*/
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explicit symbol_table(std::shared_ptr<symbol_table> scope = nullptr)
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: outer_scope(scope)
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{
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}
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iterator begin()
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{
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return entries.begin();
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}
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iterator end()
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{
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return entries.end();
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}
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const_iterator cbegin() const
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{
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return entries.cbegin();
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}
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const_iterator cend() const
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{
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return entries.cend();
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}
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/**
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* Looks for symbol in the table by name. Returns nothing if the symbol
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* can not be found.
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*
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* \param name Symbol name.
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* \return Symbol from the table if found.
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*/
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symbol_ptr lookup(const std::string& name)
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{
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auto entry = entries.find(name);
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if (entry != entries.cend())
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{
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return entry->second;
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}
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if (this->outer_scope != nullptr)
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{
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return this->outer_scope->lookup(name);
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}
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return nothing;
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}
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/**
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* Registers new symbol.
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*
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* \param name Symbol name.
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* \param entry Symbol information.
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*
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* \return Whether the insertion took place.
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*/
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bool enter(const std::string& name, symbol_ptr entry)
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{
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if (lookup(name) == nothing)
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{
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return entries.insert({ name, entry }).second;
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}
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else
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{
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return nothing;
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}
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}
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/**
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* Returns the outer scope or nullptr if the this is the global scope.
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*
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* \return Outer scope.
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*/
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std::shared_ptr<symbol_table> scope()
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{
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return this->outer_scope;
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}
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};
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}
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}
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