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139 lines
3.8 KiB
C++
139 lines
3.8 KiB
C++
// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
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// Exceptions. See /LICENSE for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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#ifndef EXECUTABLE_SEMANTICS_INTERPRETER_ACTION_H_
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#define EXECUTABLE_SEMANTICS_INTERPRETER_ACTION_H_
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#include <vector>
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#include "common/ostream.h"
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#include "executable_semantics/ast/expression.h"
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#include "executable_semantics/ast/pattern.h"
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#include "executable_semantics/ast/statement.h"
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#include "executable_semantics/interpreter/stack.h"
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#include "executable_semantics/interpreter/value.h"
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#include "llvm/Support/Compiler.h"
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namespace Carbon {
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class Action {
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public:
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enum class Kind {
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LValAction,
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ExpressionAction,
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PatternAction,
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StatementAction,
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};
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Action(const Value&) = delete;
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auto operator=(const Value&) -> Action& = delete;
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void AddResult(Nonnull<const Value*> result) { results_.push_back(result); }
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void Clear() {
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pos_ = 0;
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results_.clear();
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}
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static void PrintList(const Stack<Nonnull<Action*>>& ls,
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llvm::raw_ostream& out);
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void Print(llvm::raw_ostream& out) const;
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LLVM_DUMP_METHOD void Dump() const { Print(llvm::errs()); }
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// Returns the enumerator corresponding to the most-derived type of this
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// object.
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auto kind() const -> Kind { return kind_; }
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// The position or state of the action. Starts at 0 and goes up to the number
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// of subexpressions.
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//
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// pos indicates how many of the entries in the following `results` vector
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// will be filled in the next time this action is active.
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// For each i < pos, results[i] contains a pointer to a Value.
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auto pos() const -> int { return pos_; }
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void set_pos(int pos) { this->pos_ = pos; }
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// Results from a subexpression.
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auto results() const -> const std::vector<Nonnull<const Value*>>& {
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return results_;
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}
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protected:
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// Constructs an Action. `kind` must be the enumerator corresponding to the
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// most-derived type being constructed.
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explicit Action(Kind kind) : kind_(kind) {}
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private:
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int pos_ = 0;
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std::vector<Nonnull<const Value*>> results_;
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const Kind kind_;
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};
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class LValAction : public Action {
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public:
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explicit LValAction(Nonnull<const Expression*> expression)
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: Action(Kind::LValAction), expression_(expression) {}
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static auto classof(const Action* action) -> bool {
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return action->kind() == Kind::LValAction;
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}
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auto expression() const -> const Expression& { return *expression_; }
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private:
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Nonnull<const Expression*> expression_;
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};
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class ExpressionAction : public Action {
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public:
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explicit ExpressionAction(Nonnull<const Expression*> expression)
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: Action(Kind::ExpressionAction), expression_(expression) {}
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static auto classof(const Action* action) -> bool {
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return action->kind() == Kind::ExpressionAction;
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}
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auto expression() const -> const Expression& { return *expression_; }
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private:
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Nonnull<const Expression*> expression_;
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};
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class PatternAction : public Action {
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public:
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explicit PatternAction(Nonnull<const Pattern*> pattern)
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: Action(Kind::PatternAction), pattern_(pattern) {}
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static auto classof(const Action* action) -> bool {
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return action->kind() == Kind::PatternAction;
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}
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auto pattern() const -> const Pattern& { return *pattern_; }
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private:
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Nonnull<const Pattern*> pattern_;
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};
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class StatementAction : public Action {
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public:
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explicit StatementAction(Nonnull<const Statement*> statement)
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: Action(Kind::StatementAction), statement_(statement) {}
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static auto classof(const Action* action) -> bool {
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return action->kind() == Kind::StatementAction;
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}
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auto statement() const -> const Statement& { return *statement_; }
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private:
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Nonnull<const Statement*> statement_;
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};
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} // namespace Carbon
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#endif // EXECUTABLE_SEMANTICS_INTERPRETER_ACTION_H_
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