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#pragma once
// result.hpp - A possibly failed return value
//
// Copyright © 2014 Ben Longbons <b.r.longbons@gmail.com>
//
// This file is part of The Mana World (Athena server)
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
#include "fwd.hpp"
#include "../strings/rstring.hpp"
#include "option.hpp"
namespace tmwa
{
namespace result
{
enum ResultMagicFlag { magic_flag };
template<class T>
class Result
{
Option<T> success;
RString failure;
public:
Result(ResultMagicFlag, T v)
: success(Some(std::move(v))), failure()
{}
Result(ResultMagicFlag, RString msg)
: success(None), failure(std::move(msg))
{}
bool is_ok() { return success.is_some(); }
bool is_err() { return !is_ok(); }
Option<T>& get_success() { return success; }
RString& get_failure() { return failure; }
};
template<class T>
Result<T> Ok(T v)
{
return Result<T>(magic_flag, std::move(v));
}
struct Err
{
RString message;
Err(RString m) : message(std::move(m)) {}
template<class T>
operator Result<T>()
{
return Result<T>(magic_flag, message);
}
template<class T>
operator Option<Result<T>>()
{
return Some(Result<T>(magic_flag, message));
}
};
template<class T>
bool operator == (const Result<T>& l, const Result<T>& r)
{
return l.get_success() == r.get_success() && l.get_failure() == r.get_failure();
}
template<class T>
bool operator != (const Result<T>& l, const Result<T>& r)
{
return !(l == r);
}
} // namespace result
using result::Result;
using result::Ok;
using result::Err;
#define TRY(r) ({ auto _res = r; TRY_UNWRAP(_res.get_success(), return ::tmwa::Err(_res.get_failure())); })
// TODO the existence of this as a separate macro is a bug.
#define TRY_MOVE(r) ({ auto _res = r; TRY_UNWRAP(std::move(_res.get_success()), return ::tmwa::Err(_res.get_failure())); })
} // namespace tmwa
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