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//
// Created by mfritzsc on 7/12/17.
//
#ifndef TMCAGLWM_RESULT_HPP
#define TMCAGLWM_RESULT_HPP
#include <experimental/optional>
#include <functional>
namespace wm {
using std::experimental::optional;
using std::experimental::nullopt;
// We only ever return a string as an error - so just parametrize
// this over result type T
template <typename T>
struct result {
char const *e;
optional<T> t;
bool is_ok() const { return this->t != nullopt; }
bool is_err() const { return this->e != nullptr; }
T unwrap() {
if (this->e != nullptr) {
throw std::logic_error(this->e);
}
return this->t.value();
}
operator T() { return this->unwrap(); }
char const *unwrap_err() { return this->e; }
optional<T> const &ok() const { return this->t; }
optional<char const *> err() const {
return this->e ? optional<char const *>(this->e) : nullopt;
}
result<T> map_err(std::function<char const *(char const *)> f);
};
template <typename T>
struct result<T> Err(char const *e) {
return result<T>{e, nullopt};
}
template <typename T>
struct result<T> Ok(T t) {
return result<T>{nullptr, t};
}
template <typename T>
result<T> result<T>::map_err(std::function<char const *(char const *)> f) {
if (this->is_err()) {
return Err<T>(f(this->e));
}
return *this;
}
} // namespace wm
#endif // TMCAGLWM_RESULT_HPP
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