Initialize Aster project with basic structure, including Cargo configuration, lexer, parser, interpreter, and AST definitions. Add a sample script and README documentation. Implement basic error handling and environment management for variable storage.

src/interpreter/mod.rs

@@ -0,0 +1,55 @@
+pub mod env;
+pub mod interpreter;
+
+pub use env::Env;
+pub use interpreter::Interpreter;
+
+use std::rc::Rc;
+use std::cell::RefCell;
+use std::fmt;
+
+pub type NativeFn = fn(Vec<Value>) -> Value;
+
+#[derive(Clone)]
+pub enum Value {
+    Number(f64),
+    String(String),
+    Bool(bool),
+    Nil,
+    Function(Rc<Function>),
+    NativeFunction(NativeFn),
+}
+
+impl std::fmt::Debug for Value {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        match self {
+            Value::Number(n) => write!(f, "Number({:?})", n),
+            Value::String(s) => write!(f, "String({:?})", s),
+            Value::Bool(b) => write!(f, "Bool({:?})", b),
+            Value::Nil => write!(f, "Nil"),
+            Value::Function(_) => write!(f, "Function(...)"),
+            Value::NativeFunction(_) => write!(f, "NativeFunction(...)"),
+        }
+    }
+}
+
+impl fmt::Display for Value {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self {
+            Value::Number(n) => write!(f, "{}", n),
+            Value::String(s) => write!(f, "{}", s),
+            Value::Bool(b) => write!(f, "{}", b),
+            Value::Nil => write!(f, "nil"),
+            Value::Function(_) => write!(f, "<function>"),
+            Value::NativeFunction(_) => write!(f, "<native function>"),
+        }
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct Function {
+    pub params: Vec<String>,
+    pub body: Vec<crate::ast::Stmt>,
+    pub env: Rc<RefCell<Env>>, // 闭包捕获环境
+    pub name: Option<String>,
+}