Refactor Tuple and Record to share ValueList

Introduce `ValueList` type alias for `Rc<Vec<Value>>` to reduce
boilerplate and improve readability.
Add `as_slice()` method to `Value` to provide a unified way to access
the underlying values of Tuples and Records.
Update `flatten_value` and `unpack` in `VM` to utilize the new
`as_slice()` method, simplifying logic and improving consistency.

src/ast/types.rs

@@ -55,12 +55,16 @@ pub trait Object: fmt::Debug {
     fn as_any(&self) -> &dyn Any;
 }
 
+/// A shared sequence of values, used by both Tuples and Records.
+pub type ValueList = Rc<Vec<Value>>;
+
 /// Internal storage for Records to allow sharing schema (keys) between instances.
 #[derive(Debug, Clone)]
 pub struct RecordData {
     /// Names for slots.
     pub keys: Rc<Vec<Keyword>>,
-    pub values: Vec<Value>,
+    /// The actual values, potentially shared with a Tuple.
+    pub values: ValueList,
 }
 
 /// Core data value in Myc Script (similar to TDataValue)
@@ -73,7 +77,7 @@ pub enum Value {
     DateTime(i64),
     Text(Rc<str>),
     Keyword(Keyword),
-    Tuple(Rc<Vec<Value>>),
+    Tuple(ValueList),
     Record(Rc<RecordData>),
     Function(Rc<dyn Fn(Vec<Value>) -> Value>),
     Object(Rc<dyn Object>), // For compiled Closures and other opaque types
@@ -225,12 +229,24 @@ impl Value {
         }
     }
 
+    /// Returns the underlying values as a slice if this is a Tuple or Record.
+    pub fn as_slice(&self) -> Option<&[Value]> {
+        match self {
+            Value::Tuple(v) => Some(v),
+            Value::Record(r) => Some(&r.values),
+            _ => None,
+        }
+    }
+
     pub fn make_tuple(values: Vec<Value>) -> Self {
         Value::Tuple(Rc::new(values))
     }
 
     pub fn make_record(keys: Vec<Keyword>, values: Vec<Value>) -> Self {
-        Value::Record(Rc::new(RecordData { keys: Rc::new(keys), values }))
+        Value::Record(Rc::new(RecordData { 
+            keys: Rc::new(keys), 
+            values: Rc::new(values) 
+        }))
     }
 
     pub fn static_type(&self) -> StaticType {