Add prelude and while macro

This commit introduces a new prelude file that defines the `while` macro
and registers it during environment bootstrapping. The `again` macro has
been updated to accept multiple arguments for its recursive call, and
several examples have been adjusted to reflect this change.
Additionally, the `MacroRegistry` in the compiler is now cloneable and
can be moved out of the `MacroExpander`.

examples/again.myc

@@ -5,6 +5,6 @@
   (def factorial (fn [n acc]
     (if (= n 0)
       acc
-      (again [(- n 1) (* acc n)]))))
+      (again (- n 1) (* acc n)))))
 
   (factorial 5 1))

examples/record_optimizations.myc

@@ -1,17 +1,8 @@
 ;; Benchmark: 1.7ms
 ;; Benchmark-Repeat: 3
-;; Benchmark: TBD
 ;; Tests the effect of record inlining and field lookup optimization
 ;; Output: 10000
 (do
-  (macro while [cond body]
-    `(do
-       (def _while_loop (fn []
-         (if ~cond
-             (do ~body (_while_loop))
-             ...)))
-       (_while_loop)))
-
   (def config {:start 0 :limit 10000 :step 2})
   (def x (.start config))
 

src/ast/compiler/macros.rs

@@ -22,6 +22,7 @@ struct ExpansionState<'a> {
 type MacroMap = HashMap<Rc<str>, (Vec<Rc<str>>, Node<UntypedKind>)>;
 
 /// A registry for macro declarations.
+#[derive(Clone)]
 pub struct MacroRegistry {
     scopes: Vec<MacroMap>,
 }
@@ -78,6 +79,10 @@ impl<E: MacroEvaluator> MacroExpander<E> {
         }
     }
 
+    pub fn into_registry(self) -> MacroRegistry {
+        self.registry
+    }
+
     pub fn expand(&mut self, node: Node<UntypedKind>) -> Result<Node<UntypedKind>, String> {
         self.expand_recursive(node)
     }

src/ast/environment.rs

@@ -32,6 +32,7 @@ pub struct Environment {
     pub monomorph_cache: Rc<RefCell<MonoCache>>,
     pub debug_mode: bool,
     pub optimization: bool,
+    pub macro_registry: Rc<RefCell<MacroRegistry>>,
 }
 
 struct EnvFunctionRegistry {
@@ -104,6 +105,7 @@ impl Environment {
             monomorph_cache: Rc::new(RefCell::new(HashMap::new())),
             debug_mode: false,
             optimization: true,
+            macro_registry: Rc::new(RefCell::new(MacroRegistry::new())),
         };
         env.register_stdlib();
         env
@@ -119,7 +121,15 @@ impl Environment {
             global_types: self.global_types.clone(),
             global_values: self.global_values.clone(),
         };
-        MacroExpander::new(MacroRegistry::new(), evaluator)
+        MacroExpander::new(self.macro_registry.borrow().clone(), evaluator)
+    }
+
+    fn eval_prelude(&self, source: &str) {
+        let mut parser = crate::ast::parser::Parser::new(source).expect("Failed to parse prelude");
+        let untyped_ast = parser.parse_expression().expect("Failed to parse prelude expression");
+        let mut expander = self.get_expander();
+        let _ = expander.expand(untyped_ast).expect("Failed to expand prelude");
+        *self.macro_registry.borrow_mut() = expander.into_registry();
     }
 
     pub fn register_native(
@@ -174,6 +184,7 @@ impl Environment {
 
     fn register_stdlib(&self) {
         rtl::register(self);
+        self.eval_prelude(include_str!("rtl/prelude.myc"));
     }
 
     pub fn dump_ast(&self, source: &str) -> Result<String, String> {

src/ast/parser.rs

@@ -153,10 +153,23 @@ impl<'a> Parser<'a> {
     }
 
     fn parse_again(&mut self, identity: Identity) -> Result<Node<UntypedKind>, String> {
-        let args = Box::new(self.parse_expression()?);
+        let mut elements = Vec::new();
+
+        while *self.peek() != TokenKind::RightParen && *self.peek() != TokenKind::EOF {
+            elements.push(self.parse_expression()?);
+        }
+
+        let args_node = Node {
+            identity: identity.clone(),
+            kind: UntypedKind::Tuple { elements },
+            ty: (),
+        };
+
         Ok(Node {
             identity,
-            kind: UntypedKind::Again { args },
+            kind: UntypedKind::Again {
+                args: Box::new(args_node),
+            },
             ty: (),
         })
     }

src/ast/rtl/prelude.myc

@@ -0,0 +1,9 @@
+;; Myc Prelude
+;; This file is evaluated during Environment bootstrapping.
+;; It contains standard macros and functions.
+
+(macro while [cond body]
+  `((fn [] (if ~cond
+             (do ~body (again))
+           )))
+)

src/integration_test.rs

@@ -267,7 +267,7 @@ mod tests {
     #[should_panic(expected = "'again' is only allowed in tail position to avoid dead code.")]
     fn test_again_non_tail_panic() {
         let env = Environment::new();
-        let source = "(do (def f (fn [x] (do (again [(- x 1)]) x))) (f 5))";
+        let source = "(do (def f (fn [x] (do (again (- x 1)) x))) (f 5))";
         // This will trigger the TCO pass which contains the validation logic
         let _ = env.run_script(source);
     }

test_while.myc

@@ -0,0 +1 @@
+(while (< 1 2) (print 1))