Add <Alt-b> for input navigation

Move backwards until first non alphanumeric occurence.

src/components/utils/input.rs

@@ -120,6 +120,19 @@ impl Input {
                 self.cursor_position = 0;
                 return (Some(key), true);
             }
+            Key::Alt('b') => {
+                if self.cannot_go_left() {
+                    return (Some(key), false);
+                }
+
+                let new_cursor_index = self.cursor_index_backwards_until(&is_nonalphanumeric);
+                self.cursor_index = new_cursor_index;
+                self.cursor_position = self.value[0..self.cursor_index]
+                    .iter()
+                    .collect::<String>()
+                    .width() as u16;
+                return (Some(key), true);
+            }
             Key::Ctrl('w') => {
                 if self.cannot_go_left() {
                     return (Some(key), false);
@@ -268,4 +281,19 @@ mod test {
         assert_eq!(input.value, vec!['a', '-', 'd']);
         assert_eq!(input.cursor_index, 2);
     }
+
+    #[test]
+    fn test_goes_til_nonalphanumeric_for_alt_b() {
+        let mut input = Input::new();
+        input.value = vec!['a', '-', 'c', 'd'];
+        input.cursor_index = 3;
+        input.cursor_position = input.value_width();
+
+        let (matched_key, input_changed) = input.handle_key(Key::Alt('b'));
+
+        assert_eq!(matched_key, Some(Key::Alt('b')));
+        assert_eq!(input_changed, true);
+        assert_eq!(input.value, vec!['a', '-', 'c', 'd']);
+        assert_eq!(input.cursor_index, 2);
+    }
 }

src/event/key.rs

@@ -69,6 +69,7 @@ pub enum Key {
     Char(char),
     Ctrl(char),
     Alt(char),
+    AltBackspace,
     Unknown,
 }
 
@@ -135,6 +136,10 @@ impl From<event::KeyEvent> for Key {
                 code: event::KeyCode::Esc,
                 ..
             } => Key::Esc,
+            event::KeyEvent {
+                code: event::KeyCode::Backspace,
+                modifiers: event::KeyModifiers::ALT,
+            } => Key::AltBackspace,
             event::KeyEvent {
                 code: event::KeyCode::Backspace,
                 ..