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183 lines
5.5 KiB
C++
183 lines
5.5 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_AST_STATEMENT_H_
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#define EXECUTABLE_SEMANTICS_AST_STATEMENT_H_
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#include <list>
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#include "executable_semantics/ast/expression.h"
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namespace Carbon {
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enum class StatementKind {
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ExpressionStatement,
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Assign,
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VariableDefinition,
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If,
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Return,
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Sequence,
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Block,
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While,
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Break,
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Continue,
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Match,
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Continuation, // Create a first-class continuation.
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Run, // Run a continuation to the next await or until it finishes..
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Await, // Pause execution of the continuation.
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};
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struct Statement;
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struct ExpressionStatement {
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static constexpr StatementKind Kind = StatementKind::ExpressionStatement;
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const Expression* exp;
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};
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struct Assign {
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static constexpr StatementKind Kind = StatementKind::Assign;
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const Expression* lhs;
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const Expression* rhs;
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};
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struct VariableDefinition {
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static constexpr StatementKind Kind = StatementKind::VariableDefinition;
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const Expression* pat;
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const Expression* init;
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};
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struct If {
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static constexpr StatementKind Kind = StatementKind::If;
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const Expression* cond;
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const Statement* then_stmt;
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const Statement* else_stmt;
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};
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struct Return {
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static constexpr StatementKind Kind = StatementKind::Return;
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const Expression* exp;
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};
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struct Sequence {
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static constexpr StatementKind Kind = StatementKind::Sequence;
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const Statement* stmt;
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const Statement* next;
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};
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struct Block {
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static constexpr StatementKind Kind = StatementKind::Block;
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const Statement* stmt;
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};
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struct While {
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static constexpr StatementKind Kind = StatementKind::While;
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const Expression* cond;
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const Statement* body;
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};
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struct Break {
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static constexpr StatementKind Kind = StatementKind::Break;
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};
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struct Continue {
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static constexpr StatementKind Kind = StatementKind::Continue;
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};
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struct Match {
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static constexpr StatementKind Kind = StatementKind::Match;
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const Expression* exp;
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std::list<std::pair<const Expression*, const Statement*>>* clauses;
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};
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struct Continuation {
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static constexpr StatementKind Kind = StatementKind::Continuation;
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std::string continuation_variable;
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const Statement* body;
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};
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struct Run {
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static constexpr StatementKind Kind = StatementKind::Run;
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const Expression* argument;
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};
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struct Await {
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static constexpr StatementKind Kind = StatementKind::Await;
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};
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struct Statement {
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// Constructors
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static auto MakeExpressionStatement(int line_num, const Expression* exp)
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-> const Statement*;
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static auto MakeAssign(int line_num, const Expression* lhs,
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const Expression* rhs) -> const Statement*;
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static auto MakeVariableDefinition(int line_num, const Expression* pat,
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const Expression* init)
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-> const Statement*;
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static auto MakeIf(int line_num, const Expression* cond,
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const Statement* then_stmt, const Statement* else_stmt)
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-> const Statement*;
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static auto MakeReturn(int line_num, const Expression* e) -> const Statement*;
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static auto MakeSequence(int line_num, const Statement* s1,
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const Statement* s2) -> const Statement*;
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static auto MakeBlock(int line_num, const Statement* s) -> const Statement*;
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static auto MakeWhile(int line_num, const Expression* cond,
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const Statement* body) -> const Statement*;
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static auto MakeBreak(int line_num) -> const Statement*;
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static auto MakeContinue(int line_num) -> const Statement*;
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static auto MakeMatch(
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int line_num, const Expression* exp,
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std::list<std::pair<const Expression*, const Statement*>>* clauses)
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-> const Statement*;
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// Returns an AST node for a continuation statement give its line number and
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// contituent parts.
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//
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// __continuation <continuation_variable> {
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// <body>
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// }
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static auto MakeContinuation(int line_num, std::string continuation_variable,
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const Statement* body) -> const Statement*;
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// Returns an AST node for a run statement give its line number and argument.
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//
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// __run <argument>;
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static auto MakeRun(int line_num, const Expression* argument)
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-> const Statement*;
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// Returns an AST node for an await statement give its line number.
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//
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// __await;
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static auto MakeAwait(int line_num) -> const Statement*;
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auto GetExpressionStatement() const -> const ExpressionStatement&;
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auto GetAssign() const -> const Assign&;
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auto GetVariableDefinition() const -> const VariableDefinition&;
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auto GetIf() const -> const If&;
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auto GetReturn() const -> const Return&;
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auto GetSequence() const -> const Sequence&;
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auto GetBlock() const -> const Block&;
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auto GetWhile() const -> const While&;
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auto GetBreak() const -> const Break&;
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auto GetContinue() const -> const Continue&;
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auto GetMatch() const -> const Match&;
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auto GetContinuation() const -> const Continuation&;
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auto GetRun() const -> const Run&;
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auto GetAwait() const -> const Await&;
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inline auto tag() const -> StatementKind {
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return std::visit([](const auto& t) { return t.Kind; }, value);
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}
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int line_num;
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private:
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std::variant<ExpressionStatement, Assign, VariableDefinition, If, Return,
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Sequence, Block, While, Break, Continue, Match, Continuation,
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Run, Await>
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value;
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};
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void PrintStatement(const Statement*, int);
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} // namespace Carbon
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#endif // EXECUTABLE_SEMANTICS_AST_STATEMENT_H_
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