diff --git a/src/bytecode.rs b/src/bytecode.rs
index 11bd434..7371145 100644
--- a/src/bytecode.rs
+++ b/src/bytecode.rs
@@ -32,8 +32,6 @@ pub enum OpCode {
     /// [ .. func args @ .. ] consume (`arity` + 2) elements, call `func` with args` of length `arity`
     /// Example: __add 1 2 => [ LookUp("__add") Const(1) Const(2) Call(2) ]
     Call { arity: usize },
-    /// return a value
-    Ret,
     /// make a function
     Func { idx: ThunkIdx },
     /// push param `sym` into TOS
diff --git a/src/ty/common.rs b/src/ty/common.rs
index 127b5ab..7d17366 100644
--- a/src/ty/common.rs
+++ b/src/ty/common.rs
@@ -8,7 +8,7 @@ pub struct Catchable {
     msg: Option<String>,
 }
 
-#[derive(Debug, Clone, Hash, PartialEq, Eq, Constructor)]
+#[derive(Debug, Clone, Hash, PartialEq, Eq, PartialOrd, Ord, Constructor)]
 pub struct Symbol(EcoString);
 
 impl<T: Into<EcoString>> From<T> for Symbol {
@@ -24,3 +24,12 @@ impl Deref for Symbol {
     }
 }
 
+impl Symbol {
+    pub fn into_inner(self) -> EcoString {
+        self.0
+    }
+
+    pub fn as_inner(&self) -> &EcoString {
+        &self.0
+    }
+}
diff --git a/src/ty/internal/attrset.rs b/src/ty/internal/attrset.rs
index 0551888..b3e603b 100644
--- a/src/ty/internal/attrset.rs
+++ b/src/ty/internal/attrset.rs
@@ -43,9 +43,13 @@ impl AttrSet {
         self
     }
 
-    pub fn to_data(self) -> HashTrieMapSync<Symbol, Value> {
+    pub fn into_inner(self) -> HashTrieMapSync<Symbol, Value> {
         self.data
     }
+
+    pub fn as_inner(&self) -> &HashTrieMapSync<Symbol, Value> {
+        &self.data
+    }
 }
 
 impl ToPublic for AttrSet {
diff --git a/src/ty/internal/func.rs b/src/ty/internal/func.rs
index 69c16c0..44d0424 100644
--- a/src/ty/internal/func.rs
+++ b/src/ty/internal/func.rs
@@ -1,8 +1,9 @@
 use ecow::EcoString;
+use itertools::Itertools;
 use rpds::HashTrieMap;
 
 use crate::bytecode::{OpCodes, ThunkIdx};
-use crate::ty::internal::Value;
+use crate::ty::internal::{Thunk, Value};
 
 use crate::vm::{LockedEnv, VM};
 
@@ -39,7 +40,38 @@ impl Func {
 
         match self.param.unwrap() {
             Ident(ident) => env.enter(HashTrieMap::new_sync().insert(ident.into(), arg)),
-            Formals { .. } => todo!()
+            Formals {
+                formals,
+                ellipsis,
+                alias,
+            } => {
+                let arg = arg.unwrap_attr_set();
+                let mut new = HashTrieMap::new_sync();
+                if !ellipsis
+                    && arg
+                        .as_inner()
+                        .iter()
+                        .map(|(k, _)| k.as_inner())
+                        .sorted()
+                        .ne(formals.iter().map(|(k, _)| k).sorted())
+                {
+                    todo!()
+                }
+                for (formal, default) in formals {
+                    // let arg = if let Some(default) = default {
+                    //     arg.select(format)
+                    // }
+                    let arg = arg
+                        .select(formal.clone().into())
+                        .or_else(|| default.map(|idx| Value::Thunk(Thunk(idx))))
+                        .unwrap();
+                    new.insert_mut(formal.into(), arg);
+                }
+                if let Some(alias) = alias {
+                    new.insert_mut(alias.into(), Value::AttrSet(arg));
+                }
+                env.enter(new);
+            }
         }
 
         vm.eval(self.opcodes, &mut env).unwrap()
diff --git a/src/vm/test.rs b/src/vm/test.rs
index 4691c7d..aedc548 100644
--- a/src/vm/test.rs
+++ b/src/vm/test.rs
@@ -173,4 +173,7 @@ fn test_func() {
     test_expr("(x: x) 1", int!(1));
     test_expr("(x: x) (x: x) 1", int!(1));
     test_expr("(x: y: x + y) 1 1", int!(2));
+    test_expr("({ x, y }: x + y) { x = 1; y = 2; }", int!(3));
+    test_expr("({ x, y, ... }: x + y) { x = 1; y = 2; z = 3; }", int!(3));
+    test_expr("(inputs@{ x, y, ... }: x + inputs.y) { x = 1; y = 2; z = 3; }", int!(3));
 }
diff --git a/src/vm/vm.rs b/src/vm/vm.rs
index 290b2b4..d4c25f6 100644
--- a/src/vm/vm.rs
+++ b/src/vm/vm.rs
@@ -111,9 +111,6 @@ impl VM {
             OpCode::SetAlias { sym } => {
                 stack.tos_mut()?.as_mut().unwrap_func().set_alias(sym);
             }
-            OpCode::Ret => {
-                todo!()
-            }
             OpCode::UnOp { op } => {
                 use UnOp::*;
                 let value = stack.pop()?;
@@ -200,7 +197,7 @@ impl VM {
                 )?;
             }
             OpCode::EnterEnv => {
-                env.enter(stack.pop()?.unwrap_attr_set().to_data());
+                env.enter(stack.pop()?.unwrap_attr_set().into_inner());
             }
             OpCode::LeaveEnv => {
                 env.leave();