Add unwrap_or method to Result class

GregoryKogan · Dec 26, 2023 · 158b895 · 158b895
1 parent 26d8263
commit 158b895
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Showing 2 changed files with 14 additions and 0 deletions.
diff --git a/src/result.h b/src/result.h
@@ -39,6 +39,7 @@ template <typename T, typename E> class Result {
   [[nodiscard]] auto is_err() const noexcept -> bool;
 
   [[nodiscard]] auto unwrap() const -> T;
+  [[nodiscard]] auto unwrap_or(const T &default_value) const noexcept -> T;
   [[nodiscard]] auto unwrap_err() const -> E;
 
   /// @brief `true` if the Result is successful, `false` otherwise.
@@ -137,6 +138,17 @@ template <typename T, typename E> inline auto Result<T, E>::unwrap() const -> T
   return std::get<ContentType::Value>(content_);
 }
 
+/// @brief Returns the value of a successful Result or a default value if the Result is unsuccessful.
+/// @tparam T
+/// @tparam E
+/// @param default_value
+template <typename T, typename E> inline auto Result<T, E>::unwrap_or(const T &default_value) const noexcept -> T {
+  try {
+    if (is_ok()) { return unwrap(); }
+  } catch (const std::exception &e) { return default_value; }
+  return default_value;
+}
+
 /// @brief Returns the error of an unsuccessful Result.
 /// @return E
 /// @throw std::runtime_error if the Result is successful.

diff --git a/tests/unwrap.cpp b/tests/unwrap.cpp
@@ -7,6 +7,7 @@ TEST(Unwrap, Ok) {
   res::Result<int, std::string> result = res::Ok(value);
 
   EXPECT_EQ(result.unwrap(), value);
+  EXPECT_EQ(result.unwrap_or(0), value);
   EXPECT_THROW(auto res = result.unwrap_err(), std::runtime_error);
 }
 
@@ -16,4 +17,5 @@ TEST(Unwrap, Err) {
 
   EXPECT_EQ(result.unwrap_err(), value);
   EXPECT_THROW(auto res = result.unwrap(), std::runtime_error);
+  EXPECT_EQ(result.unwrap_or(0), 0);
 }