From 575489e3f7335a6c903b6f1d98832eaa27f244ba Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jakob=20R=C3=B6nnb=C3=A4ck?= <jakob@rowanbrook.net>
Date: Thu, 5 Feb 2026 11:17:32 +0100
Subject: [PATCH] Error Handling with Result and Option (page 32)

---
 src/main.rs | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/src/main.rs b/src/main.rs
index f159129..a150264 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -77,7 +77,26 @@ impl TodoList {
         fs::write(filename, json)?;
         Ok(())
     }
+
+    fn add_task(&mut self, description: String) -> Result<(), TodoError> {
+        if description.trim().is_empty() {
+            return Err(TodoError::InvalidInput(
+                "Task description cannot be empty".to_string(),
+            ));
+        }
+
+        let task = Task {
+            id: self.next_id,
+            description,
+            completed: false,
+        };
+
+        self.tasks.push(task);
+        self.next_id += 1;
+        Ok(())
+    }
 }
+
 fn main() {
     let cli = Cli::parse();
     match cli.command {