result: add some more functionality

Signed-off-by: Marcus Fritzsch <marcus_fritzsch@mentor.com>

diff --git a/src/result.hpp b/src/result.hpp
index e22fde9..4768d9f 100644 (file)
--- a/src/result.hpp
+++ b/src/result.hpp
@@ -6,6 +6,7 @@
 #define TMCAGLWM_RESULT_HPP
 
 #include <experimental/optional>
+#include <functional>
 
 namespace wm {
 
@@ -34,6 +35,14 @@ struct result {
    }
 
    char const *unwrap_err() { return this->e; }
+
+   optional<T> ok() const { return this->t; }
+   optional<char const *> err() const { return optional<char const *>(this->e); }
+
+   template <typename U>
+   result<U> map(std::function<U(T)> f);
+
+   result<T> map_err(std::function<char const *(char const *)> f);
 };
 
 template <typename T>
@@ -46,6 +55,23 @@ struct result<T> Ok(T t) {
    return result<T>{nullptr, t};
 }
 
+template <typename T>
+template <typename U>
+result<U> result<T>::map(std::function<U(T)> f) {
+   if (this->is_ok()) {
+      return Ok<U>(f(this->unwrap()));
+   }
+   return Err<U>(this->e);
+}
+
+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