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carbon-lang/executable_semantics/interpreter/value.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_INTERPRETER_VALUE_H_
#define EXECUTABLE_SEMANTICS_INTERPRETER_VALUE_H_
#include <list>
#include <optional>
#include <string>
#include <variant>
#include <vector>
#include "common/ostream.h"
#include "executable_semantics/ast/function_definition.h"
#include "executable_semantics/ast/statement.h"
#include "executable_semantics/interpreter/address.h"
#include "executable_semantics/interpreter/field_path.h"
#include "executable_semantics/interpreter/stack.h"
#include "llvm/Support/Compiler.h"
namespace Carbon {
struct Value;
using VarValues = std::list<std::pair<std::string, const Value*>>;
auto FindInVarValues(const std::string& field, const VarValues& inits)
-> const Value*;
auto FieldsEqual(const VarValues& ts1, const VarValues& ts2) -> bool;
// A TupleElement represents the value of a single tuple field.
struct TupleElement {
// The field name.
std::string name;
// The field's value.
const Value* value;
};
enum class ValKind {
IntValue,
FunctionValue,
PointerValue,
BoolValue,
StructValue,
AlternativeValue,
TupleValue,
IntType,
BoolType,
TypeType,
FunctionType,
PointerType,
AutoType,
StructType,
ChoiceType,
ContinuationType, // The type of a continuation.
VariableType, // e.g. generic type parameters
BindingPlaceholderValue,
AlternativeConstructorValue,
ContinuationValue // A first-class continuation value.
};
struct Frame; // used by continuation
struct IntValue {
static constexpr ValKind Kind = ValKind::IntValue;
int value;
};
struct FunctionValue {
static constexpr ValKind Kind = ValKind::FunctionValue;
std::string name;
const Value* param;
const Statement* body;
};
struct PointerValue {
static constexpr ValKind Kind = ValKind::PointerValue;
Address value;
};
struct BoolValue {
static constexpr ValKind Kind = ValKind::BoolValue;
bool value;
};
struct StructValue {
static constexpr ValKind Kind = ValKind::StructValue;
const Value* type;
const Value* inits;
};
struct AlternativeConstructorValue {
static constexpr ValKind Kind = ValKind::AlternativeConstructorValue;
std::string alt_name;
std::string choice_name;
};
struct AlternativeValue {
static constexpr ValKind Kind = ValKind::AlternativeValue;
std::string alt_name;
std::string choice_name;
const Value* argument;
};
struct TupleValue {
static constexpr ValKind Kind = ValKind::TupleValue;
std::vector<TupleElement> elements;
// Returns the value of the field named `name` in this tuple, or
// null if there is no such field.
auto FindField(const std::string& name) const -> const Value*;
};
struct BindingPlaceholderValue {
static constexpr ValKind Kind = ValKind::BindingPlaceholderValue;
// nullopt represents the `_` placeholder
std::optional<std::string> name;
const Value* type;
};
struct IntType {
static constexpr ValKind Kind = ValKind::IntType;
};
struct BoolType {
static constexpr ValKind Kind = ValKind::BoolType;
};
struct TypeType {
static constexpr ValKind Kind = ValKind::TypeType;
};
struct FunctionType {
static constexpr ValKind Kind = ValKind::FunctionType;
std::vector<GenericBinding> deduced;
const Value* param;
const Value* ret;
};
struct PointerType {
static constexpr ValKind Kind = ValKind::PointerType;
const Value* type;
};
struct AutoType {
static constexpr ValKind Kind = ValKind::AutoType;
};
struct StructType {
static constexpr ValKind Kind = ValKind::StructType;
std::string name;
VarValues fields;
VarValues methods;
};
struct ChoiceType {
static constexpr ValKind Kind = ValKind::ChoiceType;
std::string name;
VarValues alternatives;
};
struct ContinuationType {
static constexpr ValKind Kind = ValKind::ContinuationType;
};
struct VariableType {
static constexpr ValKind Kind = ValKind::VariableType;
std::string name;
};
struct ContinuationValue {
static constexpr ValKind Kind = ValKind::ContinuationValue;
std::vector<Frame*> stack;
};
struct Value {
// Constructors
// Return a first-class continuation represented by the
// given stack, down to the nearest enclosing `__continuation`.
static auto MakeContinuationValue(std::vector<Frame*> stack) -> Value*;
static auto MakeIntValue(int i) -> const Value*;
static auto MakeBoolValue(bool b) -> const Value*;
static auto MakeFunctionValue(std::string name, const Value* param,
const Statement* body) -> const Value*;
static auto MakePointerValue(Address addr) -> const Value*;
static auto MakeStructValue(const Value* type, const Value* inits)
-> const Value*;
static auto MakeTupleValue(std::vector<TupleElement> elts) -> const Value*;
static auto MakeAlternativeValue(std::string alt_name,
std::string choice_name,
const Value* argument) -> const Value*;
static auto MakeAlternativeConstructorValue(std::string alt_name,
std::string choice_name)
-> const Value*;
static auto MakeBindingPlaceholderValue(std::optional<std::string> name,
const Value* type) -> const Value*;
static auto MakeIntType() -> const Value*;
static auto MakeContinuationType() -> const Value*;
static auto MakeAutoType() -> const Value*;
static auto MakeBoolType() -> const Value*;
static auto MakeTypeType() -> const Value*;
static auto MakeFunctionType(std::vector<GenericBinding> deduced_params,
const Value* param, const Value* ret)
-> const Value*;
static auto MakePointerType(const Value* type) -> const Value*;
static auto MakeStructType(std::string name, VarValues fields,
VarValues methods) -> const Value*;
static auto MakeUnitTypeVal() -> const Value*;
static auto MakeChoiceType(std::string name, VarValues alts) -> const Value*;
static auto MakeVariableType(std::string name) -> const Value*;
// Access to alternatives
auto GetIntValue() const -> int;
auto GetBoolValue() const -> bool;
auto GetFunctionValue() const -> const FunctionValue&;
auto GetStructValue() const -> const StructValue&;
auto GetAlternativeConstructorValue() const
-> const AlternativeConstructorValue&;
auto GetAlternativeValue() const -> const AlternativeValue&;
auto GetTupleValue() const -> const TupleValue&;
auto GetPointerValue() const -> Address;
auto GetBindingPlaceholderValue() const -> const BindingPlaceholderValue&;
auto GetFunctionType() const -> const FunctionType&;
auto GetPointerType() const -> const PointerType&;
auto GetStructType() const -> const StructType&;
auto GetChoiceType() const -> const ChoiceType&;
auto GetVariableType() const -> const VariableType&;
auto GetContinuationValue() const -> const ContinuationValue&;
inline auto tag() const -> ValKind {
return std::visit([](const auto& t) { return t.Kind; }, value);
}
// Returns the sub-Value specified by `path`, which must be a valid field
// path for *this.
auto GetField(const FieldPath& path, int line_num) const -> const Value*;
// Returns a copy of *this, but with the sub-Value specified by `path`
// set to `field_value`. `path` must be a valid field path for *this.
auto SetField(const FieldPath& path, const Value* field_value,
int line_num) const -> const Value*;
void Print(llvm::raw_ostream& out) const;
LLVM_DUMP_METHOD void Dump() const { Print(llvm::errs()); }
private:
std::variant<IntValue, FunctionValue, PointerValue, BoolValue, StructValue,
AlternativeValue, TupleValue, IntType, BoolType, TypeType,
FunctionType, PointerType, AutoType, StructType, ChoiceType,
ContinuationType, VariableType, BindingPlaceholderValue,
AlternativeConstructorValue, ContinuationValue>
value;
};
auto CopyVal(const Value* val, int line_num) -> const Value*;
auto TypeEqual(const Value* t1, const Value* t2) -> bool;
auto ValueEqual(const Value* v1, const Value* v2, int line_num) -> bool;
} // namespace Carbon
#endif // EXECUTABLE_SEMANTICS_INTERPRETER_VALUE_H_