Refactor Examples to use assert_eq

This commit updates all example files to use `assert_eq!` for verifying
output, replacing the previous `Output:` comments. This change makes the
examples more robust and self-testing.

The benchmark results in some examples have also been slightly adjusted,
reflecting minor performance variations after the refactoring.

Additionally, a runtime panic handling mechanism has been introduced in
the VM for function calls, which improves error reporting for unexpected
panics.

src/ast/vm.rs

@@ -441,7 +441,19 @@ impl VM {
                             self.tail_call = Some((func_val, arg_vals));
                             return Ok(Value::Void);
                         }
-                        Value::Function(f) => return Ok((f.func)(&arg_vals)),
+                        Value::Function(f) => {
+                            return std::panic::catch_unwind(std::panic::AssertUnwindSafe(|| {
+                                (f.func)(&arg_vals)
+                            }))
+                            .map_err(|e| {
+                                e.downcast_ref::<String>()
+                                    .cloned()
+                                    .or_else(|| {
+                                        e.downcast_ref::<&str>().map(|s| s.to_string())
+                                    })
+                                    .unwrap_or_else(|| "runtime panic".to_string())
+                            });
+                        }
                         Value::FieldAccessor(k) => {
                             if arg_vals.len() != 1 {
                                 return Err(format!(
@@ -510,7 +522,17 @@ impl VM {
                 loop {
                     let result = match &current_func {
                         Value::Function(f) => {
-                            let res = (f.func)(&self.stack[base..]);
+                            let res = std::panic::catch_unwind(std::panic::AssertUnwindSafe(|| {
+                                (f.func)(&self.stack[base..])
+                            }))
+                            .map_err(|e| {
+                                e.downcast_ref::<String>()
+                                    .cloned()
+                                    .or_else(|| {
+                                        e.downcast_ref::<&str>().map(|s| s.to_string())
+                                    })
+                                    .unwrap_or_else(|| "runtime panic".to_string())
+                            })?;
                             self.stack.truncate(base);
                             return Ok(res);
                         }