translations: Make the code cleaner

src/logging.rs

@@ -70,12 +70,12 @@ pub enum Level {
 /// Approach 2.
 pub trait Warn {
     type Value;
-    fn ok_warn(self, msg: &str) -> Option<Self::Value>;
+    fn or_warn(self, msg: &str) -> Option<Self::Value>;
 }
 
 impl<T, E: Error> Warn for Result<T, E> {
     type Value = T;
-    fn ok_warn(self, msg: &str) -> Option<T> {
+    fn or_warn(self, msg: &str) -> Option<T> {
         self.map_err(|e| {
             eprintln!("{}: {}", msg, e);
             e
@@ -83,6 +83,16 @@ impl<T, E: Error> Warn for Result<T, E> {
     }
 }
 
+impl<T> Warn for Option<T> {
+    type Value = T;
+    fn or_warn(self, msg: &str) -> Option<T> {
+        self.or_else(|| {
+            eprintln!("{}", msg);
+            None
+        })
+    }
+}
+
 /// A mutable handler for text warnings.
 /// Approach 3.
 pub trait WarningHandler {