command: add Argument.name()

CHANGELOG.md

@@ -7,6 +7,7 @@
 **Improvements**
 
 * Add `Command.pos_args()` and `key_args()` for filtering argument types.
+* Add `Argument.name()` to identify arguments.
 
 # 0.2.0 (2024-05-05)
 

src/command.rs

@@ -53,6 +53,14 @@ pub struct Argument {
 }
 
 impl Argument {
+    /// Returns a name for the argument -- either the key, if given, or value.
+    pub fn name(&self) -> &str {
+        match self.key.as_deref() {
+            Some(key) => key,
+            None => &self.value,
+        }
+    }
+
     /// Parses the argument value as a T using core::str::parse(). Convenience
     /// method that returns an improved error message as a boxed error to ease
     /// error handling in a [`Runner`](crate::Runner).
@@ -115,6 +123,13 @@ mod tests {
         assert_eq!(cmd.key_args(), vec![&cmd.args[0], &cmd.args[1], &cmd.args[2]]);
     }
 
+    /// Tests Argument.name().
+    #[test]
+    fn argument_name() {
+        assert_eq!(arg!("value").name(), "value");
+        assert_eq!(arg!("key" => "value").name(), "key");
+    }
+
     /// Basic tests of Argument.parse(). Not comprehensive, since it dispatches
     /// to core::str::parse().
     #[test]