mirror of
https://github.com/carbon-language/carbon-lang.git
synced 2026-09-24 22:02:23 +01:00
Jeremy G. Siek
8924f5620b
* changed union of Statement to be private * changed the union in Expression to be private * changed union in Value to be private * changed AST constructors to be static methods * updates to syntax unit tests
156 lines
4.2 KiB
C++
156 lines
4.2 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 Assignment {
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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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const Expression* pat;
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const Expression* init;
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};
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struct IfStatement {
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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 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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const Statement* stmt;
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};
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struct While {
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const Expression* cond;
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const Statement* body;
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};
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struct 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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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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const Expression* argument;
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};
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struct Statement {
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// TODO: change Statement to a class and make all members private
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int line_num;
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StatementKind tag;
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// Constructors
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static auto MakeExpStmt(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 MakeVarDef(int line_num, const Expression* pat,
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const Expression* init) -> 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 MakeSeq(int line_num, const Statement* s1, const Statement* s2)
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-> 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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// Access to the alternatives
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const Expression* GetExpression() const;
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Assignment GetAssign() const;
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VariableDefinition GetVariableDefinition() const;
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IfStatement GetIf() const;
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const Expression* GetReturn() const;
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Sequence GetSequence() const;
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Block GetBlock() const;
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While GetWhile() const;
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Match GetMatch() const;
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Continuation GetContinuation() const;
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Run GetRun() const;
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private:
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union {
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const Expression* exp;
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Assignment assign;
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VariableDefinition variable_definition;
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IfStatement if_stmt;
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const Expression* return_stmt;
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Sequence sequence;
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Block block;
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While while_stmt;
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Match match_stmt;
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Continuation continuation;
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Run run;
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} u;
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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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