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carbon-lang/executable_semantics/ast/declaration.h
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// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
// Exceptions. See /LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
#ifndef EXECUTABLE_SEMANTICS_AST_DECLARATION_H_
#define EXECUTABLE_SEMANTICS_AST_DECLARATION_H_
#include <list>
#include <string>
#include "common/ostream.h"
#include "executable_semantics/ast/function_definition.h"
#include "executable_semantics/ast/member.h"
#include "executable_semantics/ast/pattern.h"
#include "executable_semantics/ast/struct_definition.h"
#include "executable_semantics/interpreter/address.h"
#include "executable_semantics/interpreter/dictionary.h"
#include "llvm/Support/Compiler.h"
namespace Carbon {
class Value;
using TypeEnv = Dictionary<std::string, const Value*>;
using Env = Dictionary<std::string, Address>;
struct TypeCheckContext {
// Symbol table mapping names of runtime entities to their type.
TypeEnv types;
// Symbol table mapping names of compile time entities to their value.
Env values;
};
enum class DeclarationKind {
FunctionDeclaration,
StructDeclaration,
ChoiceDeclaration,
VariableDeclaration,
};
struct FunctionDeclaration {
static constexpr DeclarationKind Kind = DeclarationKind::FunctionDeclaration;
FunctionDefinition definition;
};
struct StructDeclaration {
static constexpr DeclarationKind Kind = DeclarationKind::StructDeclaration;
StructDefinition definition;
};
struct ChoiceDeclaration {
static constexpr DeclarationKind Kind = DeclarationKind::ChoiceDeclaration;
int line_num;
std::string name;
std::list<std::pair<std::string, const Expression*>> alternatives;
};
// Global variable definition implements the Declaration concept.
struct VariableDeclaration {
static constexpr DeclarationKind Kind = DeclarationKind::VariableDeclaration;
int source_location;
// TODO: split this into a non-optional name and a type, initialized by
// a constructor that takes a BindingPattern and handles errors like a
// missing name.
const BindingPattern* binding;
const Expression* initializer;
};
class Declaration {
public:
static auto MakeFunctionDeclaration(FunctionDefinition definition)
-> const Declaration;
static auto MakeStructDeclaration(int line_num, std::string name,
std::list<Member*> members)
-> const Declaration;
static auto MakeChoiceDeclaration(
int line_num, std::string name,
std::list<std::pair<std::string, const Expression*>> alternatives)
-> const Declaration;
static auto MakeVariableDeclaration(int source_location,
const BindingPattern* binding,
const Expression* initializer)
-> const Declaration;
auto GetFunctionDeclaration() const -> const FunctionDeclaration&;
auto GetStructDeclaration() const -> const StructDeclaration&;
auto GetChoiceDeclaration() const -> const ChoiceDeclaration&;
auto GetVariableDeclaration() const -> const VariableDeclaration&;
void Print(llvm::raw_ostream& out) const;
LLVM_DUMP_METHOD void Dump() const { Print(llvm::errs()); }
inline auto tag() const -> DeclarationKind {
return std::visit([](const auto& t) { return t.Kind; }, value);
}
private:
std::variant<FunctionDeclaration, StructDeclaration, ChoiceDeclaration,
VariableDeclaration>
value;
};
} // namespace Carbon
#endif // EXECUTABLE_SEMANTICS_AST_DECLARATION_H_