only enter edit mode for columns with setters

src/keys.rs

@@ -65,3 +65,36 @@ impl Handle<TuiIn> for Taggart {
         Ok(None)
     }
 }
+
+impl Taggart {
+    pub fn edit_begin (&mut self) {
+        if let Some(column) = self.columns.0.get(self.column)
+            && column.setter.is_some()
+        {
+            let value = (column.getter)(&self.paths[self.cursor]);
+            let value = format!("{}", value.unwrap_or_default());
+            self.editing = Some((value.len(), value));
+        }
+    }
+    pub fn edit_cancel (&mut self) {
+        self.editing = None;
+    }
+    pub fn edit_confirm (&mut self) {
+        self.editing = None;
+    }
+    pub fn edit_insert (&mut self, c: char) {
+        if let Some((edit_index, value)) = &mut self.editing {
+            self.editing = Some((*edit_index, format!("{value}{c}")));
+        }
+    }
+    pub fn edit_backspace (&mut self) {
+        if let Some((edit_index, value)) = &mut self.editing {
+            let mut chars = value.chars();
+            chars.next_back();
+            self.editing = Some((*edit_index, chars.as_str().into()));
+        }
+    }
+    pub fn edit_delete (&mut self) {
+        todo!()
+    }
+}