Simplifies Result<T> and prevents undefined behaviour.

This commit is contained in:
Erik Kundt 2018-12-03 17:59:21 +01:00
parent 05e74d096e
commit e3accc6aa6
2 changed files with 12 additions and 29 deletions

View File

@ -28,44 +28,22 @@ namespace dev
/// Result<bool> check()
/// {
/// if (false)
/// return Result<bool>(false, "Error message.")
/// return Result<bool>("Error message.")
/// return true;
/// }
///
/// A result can also be instantiated using one of the factory methods it provides:
///
/// using BoolResult = Result<bool>;
/// BoolResult check()
/// {
/// if (false)
/// return BoolResult::failure("Error message");
/// return BoolResult::success(true);
/// }
///
///
struct ResultError { std::string reason; };
template <class ResultType>
class Result
{
public:
/// @{
/// @name Factory functions
/// Factory functions that provide a verbose way to create a result
static Result<ResultType> Ok(ResultType _value) { return Result(std::move(_value)); }
static Result<ResultType> Err() { return Result(ResultError{std::string()}); }
static Result<ResultType> Err(std::string _error) { return Result(ResultError{std::move(_error)}); }
/// @}
Result(ResultType _value): m_value(std::move(_value)) {}
Result(ResultError _error): m_error(std::move(_error.reason)) {}
Result(ResultType _value, ResultError _error): m_value(std::move(_value)), m_error(std::move(_error.reason)) {}
Result(ResultType _value): Result(_value, std::string{}) {}
Result(std::string _error): Result(ResultType{}, _error) {}
/// @{
/// @name Wrapper functions
/// Wrapper functions that provide implicit conversions to and explicit retrieval of
/// the value this result holds.
/// If the result is an error, accessing the value results in undefined behaviour.
operator ResultType const&() const { return m_value; }
ResultType& operator*() const { return m_value; }
ResultType const& get() const { return m_value; }
@ -73,9 +51,14 @@ public:
/// @}
/// @returns the error message (can be empty).
std::string const& err() const { return m_error; }
std::string const& error() const { return m_error; }
private:
explicit Result(ResultType _value, std::string _error):
m_value(std::move(_value)),
m_error(std::move(_error))
{}
ResultType m_value;
std::string m_error;
};

View File

@ -611,14 +611,14 @@ TypeResult IntegerType::unaryOperatorResult(Token _operator) const
{
// "delete" is ok for all integer types
if (_operator == Token::Delete)
return TypeResult::Ok(make_shared<TupleType>());
return TypeResult{make_shared<TupleType>()};
// we allow +, -, ++ and --
else if (_operator == Token::Add || _operator == Token::Sub ||
_operator == Token::Inc || _operator == Token::Dec ||
_operator == Token::BitNot)
return TypeResult::Ok(shared_from_this());
return TypeResult{shared_from_this()};
else
return TypeResult::Err();
return TypeResult{""};
}
bool IntegerType::operator==(Type const& _other) const