diff --git a/Cargo.lock b/Cargo.lock
index 83e50db..5107cd6 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -396,15 +396,8 @@ dependencies = [
 name = "nixjit"
 version = "0.1.0"
 dependencies = [
- "hashbrown 0.15.4",
  "nixjit_context",
- "nixjit_error",
- "nixjit_eval",
- "nixjit_hir",
- "nixjit_ir",
- "nixjit_lir",
  "nixjit_value",
- "rnix",
 ]
 
 [[package]]
@@ -425,6 +418,7 @@ dependencies = [
  "cranelift-jit",
  "cranelift-module",
  "cranelift-native",
+ "derive_more",
  "hashbrown 0.15.4",
  "itertools",
  "nixjit_builtins",
@@ -436,6 +430,8 @@ dependencies = [
  "nixjit_lir",
  "nixjit_value",
  "petgraph",
+ "replace_with",
+ "rnix",
 ]
 
 [[package]]
diff --git a/evaluator/nixjit/Cargo.toml b/evaluator/nixjit/Cargo.toml
index 4e0db2e..7b49985 100644
--- a/evaluator/nixjit/Cargo.toml
+++ b/evaluator/nixjit/Cargo.toml
@@ -4,13 +4,5 @@ version = "0.1.0"
 edition = "2024"
 
 [dependencies]
-rnix = "0.12"
-hashbrown = "0.15"
-
 nixjit_context = { path = "../nixjit_context" }
-nixjit_error = { path = "../nixjit_error" }
-nixjit_eval = { path = "../nixjit_eval" }
-nixjit_hir = { path = "../nixjit_hir" }
-nixjit_ir = { path = "../nixjit_ir" }
-nixjit_lir = { path = "../nixjit_lir" }
 nixjit_value = { path = "../nixjit_value" }
diff --git a/evaluator/nixjit/src/lib.rs b/evaluator/nixjit/src/lib.rs
index 37285d4..f16cea5 100644
--- a/evaluator/nixjit/src/lib.rs
+++ b/evaluator/nixjit/src/lib.rs
@@ -12,4 +12,3 @@
 
 #[cfg(test)]
 mod test;
-
diff --git a/evaluator/nixjit/src/test.rs b/evaluator/nixjit/src/test.rs
index eb8a851..5426ab0 100644
--- a/evaluator/nixjit/src/test.rs
+++ b/evaluator/nixjit/src/test.rs
@@ -1,22 +1,17 @@
 #![allow(unused_macros)]
 
-
 use std::collections::BTreeMap;
 
-use hashbrown::HashSet;
 use nixjit_context::Context;
-use nixjit_eval::EvalContext;
-use nixjit_hir::Downgrade;
-use nixjit_lir::ResolveContext;
 use nixjit_value::{AttrSet, Const, List, Symbol, Value};
 
 #[inline]
 fn test_expr(expr: &str, expected: Value) {
     println!("{expr}");
-    let mut ctx = Context::new();
-    let expr = rnix::Root::parse(expr).tree().expr().unwrap().downgrade(&mut ctx).unwrap();
-    ctx.resolve(expr).unwrap();
-    assert_eq!(ctx.eval(expr).unwrap().to_public(&ctx, &mut HashSet::new()), expected);
+    assert_eq!(
+        Context::new().eval(expr).unwrap(),
+        expected
+    );
 }
 
 macro_rules! map {
@@ -59,7 +54,7 @@ macro_rules! string {
 
 macro_rules! symbol {
     ($e:expr) => {
-        Symbol::from($e.to_string())
+        Symbol::from($e)
     };
 }
 
@@ -206,7 +201,10 @@ fn test_func() {
         "(inputs@{ x, y, ... }: x + inputs.y) { x = 1; y = 2; z = 3; }",
         int!(3),
     );
-    test_expr("let fix = f: let x = f x; in x; in (fix (self: { x = 1; y = self.x + 1; })).y", int!(2));
+    test_expr(
+        "let fix = f: let x = f x; in x; in (fix (self: { x = 1; y = self.x + 1; })).y",
+        int!(2),
+    );
 }
 
 #[test]
diff --git a/evaluator/nixjit_builtins/src/lib.rs b/evaluator/nixjit_builtins/src/lib.rs
index 85fdad7..60a8ceb 100644
--- a/evaluator/nixjit_builtins/src/lib.rs
+++ b/evaluator/nixjit_builtins/src/lib.rs
@@ -1,10 +1,9 @@
 use nixjit_macros::builtins;
-use nixjit_eval::EvalContext;
 
-pub trait BuiltinsContext: EvalContext {}
+pub trait BuiltinsContext {}
 
 #[builtins]
-mod builtins {
+pub mod builtins {
     use nixjit_error::{Error, Result};
     use nixjit_eval::Value;
     use nixjit_value::Const;
@@ -15,7 +14,7 @@ mod builtins {
     const FALSE: Const = Const::Bool(false);
     const NULL: Const = Const::Null;
 
-    fn add<Ctx: BuiltinsContext>(a: Value<Ctx>, b: Value<Ctx>) -> Result<Value<Ctx>> {
+    fn add(a: Value, b: Value) -> Result<Value> {
         use Value::*;
         Ok(match (a, b) {
             (Int(a), Int(b)) => Int(a + b),
@@ -28,11 +27,11 @@ mod builtins {
         })
     }
 
-    pub fn import<Ctx: BuiltinsContext>(ctx: &mut Ctx, path: Value<Ctx>) -> Result<Value<Ctx>> {
+    pub fn import<Ctx: BuiltinsContext>(ctx: &mut Ctx, path: Value) -> Result<Value> {
         todo!()
     }
 
-    fn elem_at<Ctx: BuiltinsContext>(list: Value<Ctx>, idx: Value<Ctx>) -> Result<Value<Ctx>> {
+    fn elem_at(list: Value, idx: Value) -> Result<Value> {
         todo!()
     }
 }
diff --git a/evaluator/nixjit_context/Cargo.toml b/evaluator/nixjit_context/Cargo.toml
index 210d788..033dcea 100644
--- a/evaluator/nixjit_context/Cargo.toml
+++ b/evaluator/nixjit_context/Cargo.toml
@@ -4,9 +4,12 @@ version = "0.1.0"
 edition = "2024"
 
 [dependencies]
+derive_more = { version = "2.0", features = ["full"] }
 hashbrown = "0.15"
 itertools = "0.14"
 petgraph = "0.8"
+replace_with = "0.1"
+rnix = "0.12"
 
 cranelift = "0.122"
 cranelift-module = "0.122"
diff --git a/evaluator/nixjit_context/src/lib.rs b/evaluator/nixjit_context/src/lib.rs
index 196079c..a8b1c88 100644
--- a/evaluator/nixjit_context/src/lib.rs
+++ b/evaluator/nixjit_context/src/lib.rs
@@ -1,50 +1,162 @@
-use core::mem::MaybeUninit;
 use std::cell::{OnceCell, RefCell};
 use std::rc::Rc;
 
+use derive_more::Unwrap;
 use hashbrown::{HashMap, HashSet};
-use petgraph::algo::toposort;
+use itertools::Itertools;
 use petgraph::graph::{DiGraph, NodeIndex};
 
+use nixjit_builtins::{
+    Builtins, BuiltinsContext,
+    builtins::{CONSTS_LEN, GLOBAL_LEN, SCOPED_LEN},
+};
 use nixjit_error::{Error, Result};
 use nixjit_eval::{EvalContext, Evaluate, Value};
-use nixjit_hir::{DowngradeContext, Hir};
-use nixjit_ir::{ArgIdx, ExprId, Param};
+use nixjit_hir::{Downgrade, DowngradeContext, Hir};
+use nixjit_ir::{ArgIdx, Const, ExprId, Param, PrimOp, PrimOpId};
 use nixjit_lir::{Lir, LookupResult, Resolve, ResolveContext};
 
 use nixjit_jit::{JITCompiler, JITContext, JITFunc};
+use replace_with::replace_with_and_return;
 
-#[derive(Debug)]
-struct Frame {
-    values: Vec<Value<Context>>,
-    left: usize,
+enum Scope {
+    With,
+    Let(HashMap<String, ExprId>),
+    Arg(Option<String>),
+}
+
+#[derive(Debug, Unwrap)]
+enum Ir {
+    Hir(Hir),
+    Lir(Lir),
+}
+
+impl Ir {
+    unsafe fn unwrap_hir_ref_unchecked(&self) -> &Hir {
+        if let Self::Hir(hir) = self {
+            hir
+        } else {
+            unsafe { core::hint::unreachable_unchecked() }
+        }
+    }
+
+    unsafe fn unwrap_hir_mut_unchecked(&mut self) -> &mut Hir {
+        #[cfg(debug_assertions)]
+        if let Self::Hir(hir) = self {
+            hir
+        } else {
+            unsafe { core::hint::unreachable_unchecked() }
+        }
+        #[cfg(not(debug_assertions))]
+        if let Self::Hir(hir) = self {
+            hir
+        } else {
+            unsafe { core::hint::unreachable_unchecked() }
+        }
+    }
+
+    unsafe fn unwrap_hir_unchecked(self) -> Hir {
+        if cfg!(debug_assertions) {
+            self.unwrap_hir()
+        } else if let Self::Hir(hir) = self {
+            hir
+        } else {
+            unsafe { core::hint::unreachable_unchecked() }
+        }
+    }
+
+    unsafe fn unwrap_lir_ref_unchecked(&self) -> &Lir {
+        #[cfg(debug_assertions)]
+        if let Self::Lir(lir) = self {
+            lir
+        } else {
+            unsafe { core::hint::unreachable_unchecked() }
+        }
+        #[cfg(not(debug_assertions))]
+        if let Self::Lir(lir) = self {
+            lir
+        } else {
+            panic!()
+        }
+    }
 }
 
-#[derive(Default)]
 pub struct Context {
-    hirs: Vec<RefCell<Hir>>,
-    lirs: Vec<MaybeUninit<Lir>>,
+    irs: Vec<RefCell<Ir>>,
     resolved: Vec<bool>,
-    scopes: Vec<HashMap<String, LookupResult>>,
+    scopes: Vec<Scope>,
+    args_count: usize,
+    primops: Vec<fn(&mut Context, Vec<Value>) -> Result<Value>>,
     funcs: HashMap<ExprId, Param>,
     graph: DiGraph<ExprId, ()>,
     nodes: Vec<NodeIndex>,
 
-    stack: Vec<Frame>,
-    with_scopes: Vec<Rc<HashMap<String, Value<Self>>>>,
+    stack: Vec<Vec<Value>>,
+    with_scopes: Vec<Rc<HashMap<String, Value>>>,
 
     jit: JITCompiler<Self>,
     compiled: Vec<OnceCell<JITFunc<Self>>>,
 }
 
-impl Drop for Context {
-    fn drop(&mut self) {
-        for (i, lir) in self.lirs.iter_mut().enumerate() {
-            if self.resolved[i] {
-                unsafe {
-                    lir.assume_init_drop();
-                }
-            }
+impl Default for Context {
+    fn default() -> Self {
+        let Builtins {
+            consts,
+            global,
+            scoped,
+        } = Builtins::new();
+        let global_scope = Scope::Let(
+            consts
+                .iter()
+                .enumerate()
+                .map(|(id, (k, _))| (k.to_string(), unsafe { ExprId::from(id) }))
+                .chain(global.iter().enumerate().map(|(idx, (k, _, _))| {
+                    (k.to_string(), unsafe {
+                        ExprId::from(idx + CONSTS_LEN)
+                    })
+                }))
+                .chain(core::iter::once(("builtins".to_string(), unsafe {
+                    ExprId::from(CONSTS_LEN + GLOBAL_LEN + SCOPED_LEN)
+                })))
+                .collect(),
+        );
+        let primops = global
+            .iter()
+            .map(|&(_, _, f)| f)
+            .chain(scoped.iter().map(|&(_, _, f)| f))
+            .collect();
+        let irs = consts
+            .into_iter()
+            .map(|(_, val)| Ir::Lir(Lir::Const(Const { val })))
+            .chain(
+                global
+                    .into_iter()
+                    .enumerate()
+                    .map(|(idx, (name, arity, _))| {
+                        Ir::Lir(Lir::PrimOp(PrimOp {
+                            name,
+                            arity,
+                            id: unsafe { PrimOpId::from(idx) },
+                        }))
+                    }),
+            )
+            .map(RefCell::new)
+            .collect();
+        Self {
+            irs,
+            resolved: Vec::new(),
+            scopes: vec![global_scope],
+            args_count: 0,
+            primops,
+            funcs: HashMap::new(),
+            graph: DiGraph::new(),
+            nodes: Vec::new(),
+
+            stack: Vec::new(),
+            with_scopes: Vec::new(),
+
+            jit: JITCompiler::new(),
+            compiled: Vec::new(),
         }
     }
 }
@@ -53,114 +165,166 @@ impl Context {
     pub fn new() -> Self {
         Self::default()
     }
+
+    pub fn eval(mut self, expr: &str) -> Result<nixjit_value::Value> {
+        let root = rnix::Root::parse(expr);
+        if !root.errors().is_empty() {
+            return Err(Error::ParseError(
+                root.errors().iter().map(|err| err.to_string()).join(";"),
+            ));
+        }
+        let root = root.tree().expr().unwrap().downgrade(&mut self)?;
+        self.resolve(&root)?;
+        Ok(EvalContext::eval(&mut self, &root)?.to_public(&mut HashSet::new()))
+    }
 }
 
 impl DowngradeContext for Context {
     fn new_expr(&mut self, expr: Hir) -> ExprId {
-        let id = ExprId::from(self.hirs.len());
-        self.hirs.push(expr.into());
-        self.lirs.push(MaybeUninit::uninit());
-        self.nodes.push(self.graph.add_node(id));
+        let id = unsafe { ExprId::from(self.irs.len()) };
+        self.irs.push(Ir::Hir(expr).into());
+        self.nodes.push(self.graph.add_node(unsafe { id.clone() }));
         self.resolved.push(false);
         self.compiled.push(OnceCell::new());
         id
     }
     fn with_expr<T>(&self, id: ExprId, f: impl FnOnce(&Hir, &Self) -> T) -> T {
-        let idx = usize::from(id);
-        f(&self.hirs[idx].borrow(), self)
-    }
-    fn with_expr_mut<T>(&mut self, id: ExprId, f: impl FnOnce(&mut Hir, &mut Self) -> T) -> T {
-        let idx = usize::from(id);
         unsafe {
+            let idx = id.raw();
+            f(&self.irs[idx].borrow().unwrap_hir_ref_unchecked(), self)
+        }
+    }
+    fn with_expr_mut<T>(&mut self, id: &ExprId, f: impl FnOnce(&mut Hir, &mut Self) -> T) -> T {
+        unsafe {
+            let idx = id.clone().raw();
             let self_mut = &mut *(self as *mut Self);
-            f(&mut self.hirs.get_unchecked_mut(idx).borrow_mut(), self_mut)
+            f(
+                &mut self
+                    .irs
+                    .get_unchecked_mut(idx)
+                    .borrow_mut()
+                    .unwrap_hir_mut_unchecked(),
+                self_mut,
+            )
         }
     }
 }
 
 impl ResolveContext for Context {
-    fn lookup(&self, name: &str) -> nixjit_lir::LookupResult {
+    fn lookup(&self, name: &str) -> LookupResult {
+        let mut arg_idx = 0;
         for scope in self.scopes.iter().rev() {
-            if let Some(val) = scope.get(name) {
-                return val.clone();
+            match scope {
+                Scope::Let(scope) => {
+                    if let Some(expr) = scope.get(name) {
+                        return LookupResult::Expr(unsafe { expr.clone() });
+                    }
+                }
+                Scope::Arg(ident) => {
+                    if ident.as_deref() == Some(name) {
+                        return LookupResult::Arg(unsafe { ArgIdx::from(arg_idx) });
+                    }
+                    arg_idx += 1;
+                }
+                Scope::With => return LookupResult::Unknown,
             }
         }
         LookupResult::NotFound
     }
 
-    fn new_dep(&mut self, expr: ExprId, dep: ExprId) {
-        let expr = *self.nodes.get(usize::from(expr)).unwrap();
-        let dep = *self.nodes.get(usize::from(dep)).unwrap();
-        self.graph.add_edge(expr, dep, ());
+    fn new_dep(&mut self, expr: &ExprId, dep: ExprId) {
+        unsafe {
+            let expr = expr.clone().raw();
+            let dep = dep.raw();
+            let expr = *self.nodes.get_unchecked(expr);
+            let dep = *self.nodes.get_unchecked(dep);
+            self.graph.add_edge(expr, dep, ());
+        }
     }
 
-    fn resolve(&mut self, expr: ExprId) -> Result<()> {
-        let idx = usize::from(expr);
-        if self.resolved[idx] {
-            return Ok(());
+    fn resolve(&mut self, expr: &ExprId) -> Result<()> {
+        unsafe {
+            let idx = expr.clone().raw();
+            let self_mut = &mut *(self as *mut Self);
+            replace_with_and_return(
+                &mut *self.irs.get_unchecked(idx).borrow_mut(),
+                || {
+                    Ir::Hir(Hir::Const(Const {
+                        val: nixjit_value::Const::Null,
+                    }))
+                },
+                |ir| {
+                    let hir = ir.unwrap_hir_unchecked();
+                    match hir.resolve(self_mut) {
+                        Ok(lir) => (Ok(()), Ir::Lir(lir)),
+                        Err(err) => (
+                            Err(err),
+                            Ir::Hir(Hir::Const(Const {
+                                val: nixjit_value::Const::Null,
+                            })),
+                        ),
+                    }
+                },
+            )?;
         }
-
-        let hir = self.hirs[idx].replace(nixjit_hir::Hir::Const(nixjit_ir::Const::from(false)));
-        let lir = hir.resolve(self)?;
-        self.lirs[idx].write(lir);
-        self.resolved[idx] = true;
         Ok(())
     }
 
-    fn new_func(&mut self, body: ExprId, param: Param) {
-        self.funcs.insert(body, param);
+    fn new_func(&mut self, body: &ExprId, param: Param) {
+        self.funcs.insert(unsafe { body.clone() }, param);
     }
 
     fn with_let_env<'a, T>(
         &mut self,
-        bindings: impl IntoIterator<Item = (&'a String, &'a ExprId)>,
+        bindings: impl Iterator<Item = (&'a String, &'a ExprId)>,
         f: impl FnOnce(&mut Self) -> T,
     ) -> T {
         let mut scope = HashMap::new();
         for (name, expr) in bindings {
-            scope.insert(name.clone(), LookupResult::Expr(*expr));
+            scope.insert(name.clone(), unsafe { expr.clone() });
         }
-        self.scopes.push(scope);
+        self.scopes.push(Scope::Let(scope));
         let res = f(self);
         self.scopes.pop();
         res
     }
 
     fn with_with_env<T>(&mut self, f: impl FnOnce(&mut Self) -> T) -> (bool, T) {
-        self.scopes.push(HashMap::new());
+        self.scopes.push(Scope::With);
         let res = f(self);
         self.scopes.pop();
         (true, res)
     }
 
-    fn with_param_env<'a, T>(
-        &mut self,
-        ident: Option<&'a str>,
-        f: impl FnOnce(&mut Self) -> T,
-    ) -> T {
-        let mut scope = HashMap::new();
-        if let Some(ident) = ident {
-            scope.insert(ident.to_string(), LookupResult::Arg(ArgIdx::from(0)));
-        }
-        self.scopes.push(scope);
+    fn with_param_env<T>(&mut self, ident: Option<String>, f: impl FnOnce(&mut Self) -> T) -> T {
+        self.scopes.push(Scope::Arg(ident));
+        self.args_count += 1;
         let res = f(self);
+        self.args_count -= 1;
         self.scopes.pop();
         res
     }
 }
 
 impl EvalContext for Context {
-    fn eval(&mut self, expr: ExprId) -> Result<nixjit_eval::Value<Self>> {
-        let idx = usize::from(expr);
-        let lir = unsafe { &*(self.lirs[idx].assume_init_ref() as *const Lir) };
+    fn eval(&mut self, expr: &ExprId) -> Result<nixjit_eval::Value> {
+        let idx = unsafe { expr.clone().raw() };
+        let lir = unsafe {
+            &*(self
+                .irs
+                .get_unchecked(idx)
+                .borrow()
+                .unwrap_lir_ref_unchecked() as *const Lir)
+        };
+        println!("{:#?}", self.irs);
         lir.eval(self)
     }
 
-    fn pop_frame(&mut self) -> Vec<nixjit_eval::Value<Self>> {
-        self.stack.pop().unwrap().values
+    fn pop_frame(&mut self) -> Vec<nixjit_eval::Value> {
+        self.stack.pop().unwrap()
     }
 
-    fn lookup_with<'a>(&'a self, ident: &str) -> Option<&'a nixjit_eval::Value<Self>> {
+    fn lookup_with<'a>(&'a self, ident: &str) -> Option<&'a nixjit_eval::Value> {
         for scope in self.with_scopes.iter().rev() {
             if let Some(val) = scope.get(ident) {
                 return Some(val);
@@ -169,13 +333,17 @@ impl EvalContext for Context {
         None
     }
 
-    fn lookup_arg<'a>(&'a self, offset: usize) -> Option<&'a Value<Self>> {
-        self.stack.last().and_then(|frame| frame.values.get(offset))
+    fn lookup_arg<'a>(&'a self, idx: ArgIdx) -> &'a Value {
+        unsafe {
+            let values = self.stack.last().unwrap_unchecked();
+            dbg!(values, idx);
+            &values[values.len() - idx.raw() - 1]
+        }
     }
 
     fn with_with_env<T>(
         &mut self,
-        namespace: std::rc::Rc<HashMap<String, nixjit_eval::Value<Self>>>,
+        namespace: std::rc::Rc<HashMap<String, nixjit_eval::Value>>,
         f: impl FnOnce(&mut Self) -> T,
     ) -> T {
         self.with_scopes.push(namespace);
@@ -186,53 +354,33 @@ impl EvalContext for Context {
 
     fn with_args_env<T>(
         &mut self,
-        args: Vec<nixjit_eval::Value<Self>>,
+        args: Vec<nixjit_eval::Value>,
         f: impl FnOnce(&mut Self) -> T,
-    ) -> (Vec<nixjit_eval::Value<Self>>, T) {
-        self.stack.push(Frame {
-            left: args.len(),
-            values: args,
-        });
+    ) -> (Vec<Value>, T) {
+        self.stack.push(args);
         let res = f(self);
-        (self.stack.pop().unwrap().values, res)
+        let frame = self.stack.pop().unwrap();
+        (frame, res)
     }
 
-    fn consume_arg(&mut self, func: ExprId) -> Result<bool> {
-        let Some(frame) = self.stack.last_mut() else {
-            return Ok(false);
-        };
-        if frame.left == 0 {
-            return Ok(false);
+    fn call_primop(&mut self, id: nixjit_ir::PrimOpId, args: Vec<Value>) -> Result<Value> {
+        unsafe {
+            (self.primops.get_unchecked(id.raw()))(self, args)
         }
-        frame.left -= 1;
-        let param = self.funcs.get(&func).unwrap();
-        if let Some(required) = &param.required {
-            let attrs = frame.values[frame.values.len() - frame.left - 1]
-                .as_ref()
-                .try_unwrap_attr_set()
-                .map_err(|_| Error::EvalError(format!("expected a set but found ...")))?;
-            if required.iter().any(|attr| attrs.get(attr).is_none())
-                || param.allowed.as_ref().map_or(false, |allowed| {
-                    attrs.iter().any(|(attr, _)| allowed.get(attr).is_none())
-                })
-            {
-                return Err(Error::EvalError(format!("TODO")));
-            }
-        }
-        Ok(true)
     }
 }
 
 impl JITContext for Context {
-    fn lookup_arg(&self, offset: usize) -> &nixjit_eval::Value<Self> {
-        &self.stack.last().unwrap().values[offset]
+    fn lookup_arg(&self, offset: usize) -> &nixjit_eval::Value {
+        let values = self.stack.last().unwrap();
+        &values[values.len() - offset - 1]
     }
 
-    fn lookup_stack(&self, offset: usize) -> &nixjit_eval::Value<Self> {
+    fn lookup_stack(&self, offset: usize) -> &nixjit_eval::Value {
         todo!()
     }
 
-    fn enter_with(&mut self, namespace: std::rc::Rc<HashMap<String, nixjit_eval::Value<Self>>>) {
+    fn enter_with(&mut self, namespace: std::rc::Rc<HashMap<String, nixjit_eval::Value>>) {
         self.with_scopes.push(namespace);
     }
 
@@ -240,3 +388,5 @@ impl JITContext for Context {
         self.with_scopes.pop();
     }
 }
+
+impl BuiltinsContext for Context {}
diff --git a/evaluator/nixjit_eval/src/lib.rs b/evaluator/nixjit_eval/src/lib.rs
index bf56d2c..354dbab 100644
--- a/evaluator/nixjit_eval/src/lib.rs
+++ b/evaluator/nixjit_eval/src/lib.rs
@@ -3,7 +3,7 @@ use std::rc::Rc;
 use hashbrown::HashMap;
 
 use nixjit_error::{Error, Result};
-use nixjit_ir::{self as ir, ExprId};
+use nixjit_ir::{self as ir, ArgIdx, ExprId, PrimOpId};
 use nixjit_lir as lir;
 use nixjit_value::{Const, Symbol};
 
@@ -12,35 +12,31 @@ pub use crate::value::*;
 mod value;
 
 pub trait EvalContext: Sized {
-    fn eval(&mut self, expr: ExprId) -> Result<Value<Self>>;
+    fn eval(&mut self, expr: &ExprId) -> Result<Value>;
     fn with_with_env<T>(
         &mut self,
-        namespace: Rc<HashMap<String, Value<Self>>>,
+        namespace: Rc<HashMap<String, Value>>,
         f: impl FnOnce(&mut Self) -> T,
     ) -> T;
-    fn with_args_env<T>(
-        &mut self,
-        args: Vec<Value<Self>>,
-        f: impl FnOnce(&mut Self) -> T,
-    ) -> (Vec<Value<Self>>, T);
-    fn lookup_with<'a>(&'a self, ident: &str) -> Option<&'a Value<Self>>;
-    fn lookup_arg<'a>(&'a self, offset: usize) -> Option<&'a Value<Self>>;
-    fn pop_frame(&mut self) -> Vec<Value<Self>>;
-    fn consume_arg(&mut self, func: ExprId) -> Result<bool>;
+    fn with_args_env<T>(&mut self, args: Vec<Value>, f: impl FnOnce(&mut Self) -> T) -> (Vec<Value>, T);
+    fn lookup_with<'a>(&'a self, ident: &str) -> Option<&'a Value>;
+    fn lookup_arg<'a>(&'a self, idx: ArgIdx) -> &'a Value;
+    fn pop_frame(&mut self) -> Vec<Value>;
+    fn call_primop(&mut self, id: PrimOpId, args: Vec<Value>) -> Result<Value>;
 }
 
 pub trait Evaluate<Ctx: EvalContext> {
-    fn eval(&self, ctx: &mut Ctx) -> Result<Value<Ctx>>;
+    fn eval(&self, ctx: &mut Ctx) -> Result<Value>;
 }
 
 impl<Ctx: EvalContext> Evaluate<Ctx> for ExprId {
-    fn eval(&self, ctx: &mut Ctx) -> Result<Value<Ctx>> {
-        ctx.eval(*self)
+    fn eval(&self, ctx: &mut Ctx) -> Result<Value> {
+        ctx.eval(self)
     }
 }
 
 impl<Ctx: EvalContext> Evaluate<Ctx> for lir::Lir {
-    fn eval(&self, ctx: &mut Ctx) -> Result<Value<Ctx>> {
+    fn eval(&self, ctx: &mut Ctx) -> Result<Value> {
         use lir::Lir::*;
         match self {
             AttrSet(x) => x.eval(ctx),
@@ -58,26 +54,16 @@ impl<Ctx: EvalContext> Evaluate<Ctx> for lir::Lir {
             Str(x) => x.eval(ctx),
             Var(x) => x.eval(ctx),
             Path(x) => x.eval(ctx),
-            ExprRef(expr) => expr.eval(ctx),
-            &FuncRef(func) => {
-                if ctx.consume_arg(func)? {
-                    ctx.eval(func)
-                } else {
-                    Ok(Value::Func(func))
-                }
-            },
-            &ArgRef(arg) => {
-                let idx: usize = unsafe { core::mem::transmute(arg) };
-                ctx.lookup_arg(idx)
-                    .cloned()
-                    .ok_or_else(|| Error::EvalError("argument not found".to_string()))
-            }
+            ExprRef(expr) => ctx.eval(expr),
+            FuncRef(func) => Ok(Value::Func(unsafe { func.clone() })),
+            &ArgRef(idx) => Ok(ctx.lookup_arg(idx).clone()),
+            &PrimOp(primop) => Ok(Value::PrimOp(primop)),
         }
     }
 }
 
 impl<Ctx: EvalContext> Evaluate<Ctx> for ir::AttrSet {
-    fn eval(&self, ctx: &mut Ctx) -> Result<Value<Ctx>> {
+    fn eval(&self, ctx: &mut Ctx) -> Result<Value> {
         let mut attrs = AttrSet::new(
             self.stcs
                 .iter()
@@ -99,7 +85,7 @@ impl<Ctx: EvalContext> Evaluate<Ctx> for ir::AttrSet {
 }
 
 impl<Ctx: EvalContext> Evaluate<Ctx> for ir::List {
-    fn eval(&self, ctx: &mut Ctx) -> Result<Value<Ctx>> {
+    fn eval(&self, ctx: &mut Ctx) -> Result<Value> {
         let items = self
             .items
             .iter()
@@ -111,7 +97,7 @@ impl<Ctx: EvalContext> Evaluate<Ctx> for ir::List {
 }
 
 impl<Ctx: EvalContext> Evaluate<Ctx> for ir::HasAttr {
-    fn eval(&self, ctx: &mut Ctx) -> Result<Value<Ctx>> {
+    fn eval(&self, ctx: &mut Ctx) -> Result<Value> {
         use ir::Attr::*;
         let mut val = self.lhs.eval(ctx)?;
         val.has_attr(self.rhs.iter().map(|attr| {
@@ -130,7 +116,7 @@ impl<Ctx: EvalContext> Evaluate<Ctx> for ir::HasAttr {
 }
 
 impl<Ctx: EvalContext> Evaluate<Ctx> for ir::BinOp {
-    fn eval(&self, ctx: &mut Ctx) -> Result<Value<Ctx>> {
+    fn eval(&self, ctx: &mut Ctx) -> Result<Value> {
         use ir::BinOpKind::*;
         let mut lhs = self.lhs.eval(ctx)?;
         let mut rhs = self.rhs.eval(ctx)?;
@@ -169,9 +155,9 @@ impl<Ctx: EvalContext> Evaluate<Ctx> for ir::BinOp {
             }
             Con => lhs.concat(rhs),
             Upd => lhs.update(rhs),
-            PipeL => lhs.call(vec![rhs], ctx)?,
+            PipeL => lhs.call(core::iter::once(Ok(rhs)), ctx)?,
             PipeR => {
-                rhs.call(vec![lhs], ctx)?;
+                rhs.call(core::iter::once(Ok(lhs)), ctx)?;
                 lhs = rhs;
             }
         }
@@ -180,7 +166,7 @@ impl<Ctx: EvalContext> Evaluate<Ctx> for ir::BinOp {
 }
 
 impl<Ctx: EvalContext> Evaluate<Ctx> for ir::UnOp {
-    fn eval(&self, ctx: &mut Ctx) -> Result<Value<Ctx>> {
+    fn eval(&self, ctx: &mut Ctx) -> Result<Value> {
         use ir::UnOpKind::*;
         let mut rhs = self.rhs.eval(ctx)?;
         match self.kind {
@@ -196,7 +182,7 @@ impl<Ctx: EvalContext> Evaluate<Ctx> for ir::UnOp {
 }
 
 impl<Ctx: EvalContext> Evaluate<Ctx> for ir::Select {
-    fn eval(&self, ctx: &mut Ctx) -> Result<Value<Ctx>> {
+    fn eval(&self, ctx: &mut Ctx) -> Result<Value> {
         use ir::Attr::*;
         let mut val = self.expr.eval(ctx)?;
         if let Some(default) = &self.default {
@@ -232,7 +218,7 @@ impl<Ctx: EvalContext> Evaluate<Ctx> for ir::Select {
 }
 
 impl<Ctx: EvalContext> Evaluate<Ctx> for ir::If {
-    fn eval(&self, ctx: &mut Ctx) -> Result<Value<Ctx>> {
+    fn eval(&self, ctx: &mut Ctx) -> Result<Value> {
         // TODO: Error Handling
         let cond = self.cond.eval(ctx)?;
         let cond = cond
@@ -248,21 +234,22 @@ impl<Ctx: EvalContext> Evaluate<Ctx> for ir::If {
 }
 
 impl<Ctx: EvalContext> Evaluate<Ctx> for ir::Call {
-    fn eval(&self, ctx: &mut Ctx) -> Result<Value<Ctx>> {
+    fn eval(&self, ctx: &mut Ctx) -> Result<Value> {
         let mut func = self.func.eval(ctx)?;
+        // FIXME: ?
+        let ctx_mut = unsafe { &mut *(ctx as *mut Ctx) };
         func.call(
             self.args
                 .iter()
-                .map(|arg| arg.eval(ctx))
-                .collect::<Result<_>>()?,
-            ctx,
+                .map(|arg| arg.eval(ctx)),
+            ctx_mut,
         )?;
         Ok(func.ok().unwrap())
     }
 }
 
 impl<Ctx: EvalContext> Evaluate<Ctx> for ir::With {
-    fn eval(&self, ctx: &mut Ctx) -> Result<Value<Ctx>> {
+    fn eval(&self, ctx: &mut Ctx) -> Result<Value> {
         let namespace = self.namespace.eval(ctx)?;
         ctx.with_with_env(
             namespace
@@ -275,7 +262,7 @@ impl<Ctx: EvalContext> Evaluate<Ctx> for ir::With {
 }
 
 impl<Ctx: EvalContext> Evaluate<Ctx> for ir::Assert {
-    fn eval(&self, ctx: &mut Ctx) -> Result<Value<Ctx>> {
+    fn eval(&self, ctx: &mut Ctx) -> Result<Value> {
         let cond = self.assertion.eval(ctx)?;
         let cond = cond
             .try_unwrap_bool()
@@ -289,7 +276,7 @@ impl<Ctx: EvalContext> Evaluate<Ctx> for ir::Assert {
 }
 
 impl<Ctx: EvalContext> Evaluate<Ctx> for ir::ConcatStrings {
-    fn eval(&self, ctx: &mut Ctx) -> Result<Value<Ctx>> {
+    fn eval(&self, ctx: &mut Ctx) -> Result<Value> {
         let mut parts = self
             .parts
             .iter()
@@ -310,14 +297,14 @@ impl<Ctx: EvalContext> Evaluate<Ctx> for ir::ConcatStrings {
 }
 
 impl<Ctx: EvalContext> Evaluate<Ctx> for ir::Str {
-    fn eval(&self, _: &mut Ctx) -> Result<Value<Ctx>> {
+    fn eval(&self, _: &mut Ctx) -> Result<Value> {
         let result = Value::String(self.val.clone()).ok();
         Ok(result.unwrap())
     }
 }
 
 impl<Ctx: EvalContext> Evaluate<Ctx> for ir::Const {
-    fn eval(&self, _: &mut Ctx) -> Result<Value<Ctx>> {
+    fn eval(&self, _: &mut Ctx) -> Result<Value> {
         let result = match self.val {
             Const::Null => Value::Null,
             Const::Int(x) => Value::Int(x),
@@ -330,7 +317,7 @@ impl<Ctx: EvalContext> Evaluate<Ctx> for ir::Const {
 }
 
 impl<Ctx: EvalContext> Evaluate<Ctx> for ir::Var {
-    fn eval(&self, ctx: &mut Ctx) -> Result<Value<Ctx>> {
+    fn eval(&self, ctx: &mut Ctx) -> Result<Value> {
         ctx.lookup_with(&self.sym)
             .ok_or_else(|| {
                 Error::EvalError(format!(
@@ -343,7 +330,7 @@ impl<Ctx: EvalContext> Evaluate<Ctx> for ir::Var {
 }
 
 impl<Ctx: EvalContext> Evaluate<Ctx> for ir::Path {
-    fn eval(&self, ctx: &mut Ctx) -> Result<Value<Ctx>> {
+    fn eval(&self, ctx: &mut Ctx) -> Result<Value> {
         todo!()
     }
 }
diff --git a/evaluator/nixjit_eval/src/value/attrset.rs b/evaluator/nixjit_eval/src/value/attrset.rs
index 2447f09..e0fd691 100644
--- a/evaluator/nixjit_eval/src/value/attrset.rs
+++ b/evaluator/nixjit_eval/src/value/attrset.rs
@@ -1,6 +1,6 @@
 use core::ops::Deref;
-use std::rc::Rc;
 use std::fmt::Debug;
+use std::rc::Rc;
 
 use derive_more::Constructor;
 use hashbrown::{HashMap, HashSet};
@@ -15,11 +15,11 @@ use crate::EvalContext;
 
 #[repr(transparent)]
 #[derive(Constructor, PartialEq)]
-pub struct AttrSet<Ctx: EvalContext> {
-    data: HashMap<String, Value<Ctx>>,
+pub struct AttrSet {
+    data: HashMap<String, Value>,
 }
 
-impl<Ctx: EvalContext> Debug for AttrSet<Ctx> {
+impl Debug for AttrSet {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         use Value::*;
         write!(f, "{{ ")?;
@@ -34,7 +34,7 @@ impl<Ctx: EvalContext> Debug for AttrSet<Ctx> {
     }
 }
 
-impl<Ctx: EvalContext> Clone for AttrSet<Ctx> {
+impl Clone for AttrSet {
     fn clone(&self) -> Self {
         AttrSet {
             data: self.data.clone(),
@@ -42,31 +42,31 @@ impl<Ctx: EvalContext> Clone for AttrSet<Ctx> {
     }
 }
 
-impl<Ctx: EvalContext> From<HashMap<String, Value<Ctx>>> for AttrSet<Ctx> {
-    fn from(data: HashMap<String, Value<Ctx>>) -> Self {
+impl From<HashMap<String, Value>> for AttrSet {
+    fn from(data: HashMap<String, Value>) -> Self {
         Self { data }
     }
 }
 
-impl<Ctx: EvalContext> Deref for AttrSet<Ctx> {
-    type Target = HashMap<String, Value<Ctx>>;
+impl Deref for AttrSet {
+    type Target = HashMap<String, Value>;
     fn deref(&self) -> &Self::Target {
         &self.data
     }
 }
 
-impl<Ctx: EvalContext> AttrSet<Ctx> {
+impl AttrSet {
     pub fn with_capacity(cap: usize) -> Self {
         AttrSet {
             data: HashMap::with_capacity(cap),
         }
     }
 
-    pub fn push_attr_force(&mut self, sym: String, val: Value<Ctx>) {
+    pub fn push_attr_force(&mut self, sym: String, val: Value) {
         self.data.insert(sym, val);
     }
 
-    pub fn push_attr(&mut self, sym: String, val: Value<Ctx>) {
+    pub fn push_attr(&mut self, sym: String, val: Value) {
         if self.data.get(&sym).is_some() {
             todo!()
         }
@@ -76,7 +76,7 @@ impl<Ctx: EvalContext> AttrSet<Ctx> {
     pub fn select(
         &self,
         mut path: impl DoubleEndedIterator<Item = Result<String>>,
-    ) -> Result<Value<Ctx>> {
+    ) -> Result<Value> {
         let mut data = &self.data;
         let last = path.nth_back(0).unwrap();
         for item in path {
@@ -116,15 +116,15 @@ impl<Ctx: EvalContext> AttrSet<Ctx> {
         }
     }
 
-    pub fn as_inner(&self) -> &HashMap<String, Value<Ctx>> {
+    pub fn as_inner(&self) -> &HashMap<String, Value> {
         &self.data
     }
 
-    pub fn into_inner(self: Rc<Self>) -> Rc<HashMap<String, Value<Ctx>>> {
+    pub fn into_inner(self: Rc<Self>) -> Rc<HashMap<String, Value>> {
         unsafe { core::mem::transmute(self) }
     }
 
-    pub fn from_inner(data: HashMap<String, Value<Ctx>>) -> Self {
+    pub fn from_inner(data: HashMap<String, Value>) -> Self {
         Self { data }
     }
 
@@ -137,11 +137,11 @@ impl<Ctx: EvalContext> AttrSet<Ctx> {
             .all(|((k1, v1), (k2, v2))| k1 == k2 && v1.eq_impl(v2))
     }
 
-    pub fn to_public(&self, ctx: &Ctx, seen: &mut HashSet<Value<Ctx>>) -> p::Value {
+    pub fn to_public(&self, seen: &mut HashSet<Value>) -> p::Value {
         p::Value::AttrSet(p::AttrSet::new(
             self.data
                 .iter()
-                .map(|(sym, value)| (sym.as_str().into(), value.to_public(ctx, seen)))
+                .map(|(sym, value)| (sym.as_str().into(), value.to_public(seen)))
                 .collect(),
         ))
     }
diff --git a/evaluator/nixjit_eval/src/value/func.rs b/evaluator/nixjit_eval/src/value/func.rs
index cf6886f..ffc9966 100644
--- a/evaluator/nixjit_eval/src/value/func.rs
+++ b/evaluator/nixjit_eval/src/value/func.rs
@@ -9,39 +9,59 @@ use super::Value;
 use crate::EvalContext;
 
 #[derive(Debug, Constructor)]
-pub struct FuncApp<Ctx: EvalContext> {
+pub struct FuncApp {
     pub body: ExprId,
-    pub args: Vec<Value<Ctx>>,
-    pub frame: Vec<Value<Ctx>>,
+    pub args: Vec<Value>,
+    pub frame: Vec<Value>,
 }
 
-impl<Ctx: EvalContext> Clone for FuncApp<Ctx> {
+impl Clone for FuncApp {
     fn clone(&self) -> Self {
         Self {
-            body: self.body,
+            body: unsafe { self.body.clone() },
             args: self.args.clone(),
             frame: self.frame.clone(),
         }
     }
 }
 
-impl<Ctx: EvalContext> FuncApp<Ctx> {
-    pub fn call(
+impl FuncApp {
+    pub fn call<Ctx: EvalContext>(
         self: &mut Rc<Self>,
-        new_args: Vec<Value<Ctx>>,
+        mut iter: impl Iterator<Item = Result<Value>> + ExactSizeIterator,
         ctx: &mut Ctx,
-    ) -> Result<Value<Ctx>> {
-        let FuncApp { body: expr, args, frame } = Rc::make_mut(self);
-        args.extend(new_args);
-        let (args, ret) = ctx.with_args_env(core::mem::take(args), |ctx| ctx.eval(*expr));
-        let mut ret = ret?;
-        if let Value::Func(expr) = ret {
-            let frame = ctx.pop_frame();
-            ret = Value::FuncApp(FuncApp::new(expr, args, frame).into());
-        } else if let Value::FuncApp(func) = &mut ret {
-            todo!();
-            let func = Rc::make_mut(func);
+    ) -> Result<Value> {
+        let FuncApp {
+            body: expr,
+            args,
+            frame,
+        } = Rc::make_mut(self);
+        let mut val;
+        let mut args = core::mem::take(args);
+        args.push(iter.next().unwrap()?);
+        let (ret_args, ret) = ctx.with_args_env(args, |ctx| ctx.eval(expr));
+        args = ret_args;
+        val = ret?;
+        loop {
+            if !matches!(val, Value::Func(_) | Value::FuncApp(_)) {
+                break;
+            }
+            let Some(arg) = iter.next() else {
+                break;
+            };
+            args.push(arg?);
+            if let Value::Func(expr) = val {
+                let (ret_args, ret) = ctx.with_args_env(args, |ctx| ctx.eval(&expr));
+                args = ret_args;
+                val = ret?;
+            } else if let Value::FuncApp(func) = val {
+                let mut func = Rc::unwrap_or_clone(func);
+                func.args.push(args.pop().unwrap());
+                let (ret_args, ret) = ctx.with_args_env(func.args, |ctx| ctx.eval(&func.body));
+                args = ret_args;
+                val = ret?;
+            }
         }
-        ret.ok()
+        val.ok()
     }
 }
diff --git a/evaluator/nixjit_eval/src/value/list.rs b/evaluator/nixjit_eval/src/value/list.rs
index 7a17937..7dee374 100644
--- a/evaluator/nixjit_eval/src/value/list.rs
+++ b/evaluator/nixjit_eval/src/value/list.rs
@@ -1,5 +1,5 @@
-use std::ops::Deref;
 use std::fmt::Debug;
+use std::ops::Deref;
 
 use hashbrown::HashSet;
 
@@ -10,11 +10,11 @@ use super::Value;
 use crate::EvalContext;
 
 #[derive(Default)]
-pub struct List<Ctx: EvalContext> {
-    data: Vec<Value<Ctx>>,
+pub struct List {
+    data: Vec<Value>,
 }
 
-impl<Ctx: EvalContext> Debug for List<Ctx> {
+impl Debug for List {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         write!(f, "[ ")?;
         for v in self.data.iter() {
@@ -24,7 +24,7 @@ impl<Ctx: EvalContext> Debug for List<Ctx> {
     }
 }
 
-impl<Ctx: EvalContext> Clone for List<Ctx> {
+impl Clone for List {
     fn clone(&self) -> Self {
         Self {
             data: self.data.clone(),
@@ -32,20 +32,20 @@ impl<Ctx: EvalContext> Clone for List<Ctx> {
     }
 }
 
-impl<Ctx: EvalContext, T: Into<Vec<Value<Ctx>>>> From<T> for List<Ctx> {
+impl<T: Into<Vec<Value>>> From<T> for List {
     fn from(value: T) -> Self {
         Self { data: value.into() }
     }
 }
 
-impl<Ctx: EvalContext> Deref for List<Ctx> {
-    type Target = [Value<Ctx>];
+impl Deref for List {
+    type Target = [Value];
     fn deref(&self) -> &Self::Target {
         &self.data
     }
 }
 
-impl<Ctx: EvalContext> List<Ctx> {
+impl List {
     pub fn new() -> Self {
         List { data: Vec::new() }
     }
@@ -56,7 +56,7 @@ impl<Ctx: EvalContext> List<Ctx> {
         }
     }
 
-    pub fn push(&mut self, elem: Value<Ctx>) {
+    pub fn push(&mut self, elem: Value) {
         self.data.push(elem);
     }
 
@@ -66,7 +66,7 @@ impl<Ctx: EvalContext> List<Ctx> {
         }
     }
 
-    pub fn into_inner(self) -> Vec<Value<Ctx>> {
+    pub fn into_inner(self) -> Vec<Value> {
         self.data
     }
 
@@ -75,11 +75,11 @@ impl<Ctx: EvalContext> List<Ctx> {
             && core::iter::zip(self.iter(), other.iter()).all(|(a, b)| a.eq_impl(b))
     }
 
-    pub fn to_public(&self, engine: &Ctx, seen: &mut HashSet<Value<Ctx>>) -> PubValue {
+    pub fn to_public(&self, seen: &mut HashSet<Value>) -> PubValue {
         PubValue::List(PubList::new(
             self.data
                 .iter()
-                .map(|value| value.clone().to_public(engine, seen))
+                .map(|value| value.clone().to_public(seen))
                 .collect(),
         ))
     }
diff --git a/evaluator/nixjit_eval/src/value/mod.rs b/evaluator/nixjit_eval/src/value/mod.rs
index c937b78..8cf3997 100644
--- a/evaluator/nixjit_eval/src/value/mod.rs
+++ b/evaluator/nixjit_eval/src/value/mod.rs
@@ -1,14 +1,13 @@
+use std::fmt::Debug;
 use std::hash::Hash;
 use std::process::abort;
 use std::rc::Rc;
-use std::fmt::{write, Debug};
 
 use derive_more::TryUnwrap;
 use derive_more::{IsVariant, Unwrap};
-use func::FuncApp;
 use hashbrown::HashSet;
-use nixjit_ir::ExprId;
-use replace_with::{replace_with_and_return, replace_with_or_abort};
+use nixjit_ir::{ExprId, PrimOp};
+use replace_with::replace_with_and_return;
 
 use nixjit_error::{Error, Result};
 use nixjit_value::Const;
@@ -23,28 +22,29 @@ mod primop;
 mod string;
 
 pub use attrset::*;
+pub use func::*;
 pub use list::List;
 pub use primop::*;
 
 #[repr(C, u64)]
 #[derive(IsVariant, TryUnwrap, Unwrap)]
-pub enum Value<Ctx: EvalContext> {
+pub enum Value {
     Int(i64),
     Float(f64),
     Bool(bool),
     String(String),
     Null,
     Thunk(usize),
-    AttrSet(Rc<AttrSet<Ctx>>),
-    List(Rc<List<Ctx>>),
+    AttrSet(Rc<AttrSet>),
+    List(Rc<List>),
     Catchable(String),
-    PrimOp(Rc<PrimOp<Ctx>>),
-    PrimOpApp(Rc<PrimOpApp<Ctx>>),
+    PrimOp(PrimOp),
+    PrimOpApp(Rc<PrimOpApp>),
     Func(ExprId),
-    FuncApp(Rc<FuncApp<Ctx>>),
+    FuncApp(Rc<FuncApp>),
 }
 
-impl<Ctx: EvalContext> Debug for Value<Ctx> {
+impl Debug for Value {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         use Value::*;
         match self {
@@ -65,28 +65,28 @@ impl<Ctx: EvalContext> Debug for Value<Ctx> {
     }
 }
 
-impl<Ctx: EvalContext> Clone for Value<Ctx> {
+impl Clone for Value {
     fn clone(&self) -> Self {
         use Value::*;
         match self {
             AttrSet(attrs) => AttrSet(attrs.clone()),
             List(list) => List(list.clone()),
             Catchable(catchable) => Catchable(catchable.clone()),
-            Int(x) => Int(*x),
-            Float(x) => Float(*x),
-            Bool(x) => Bool(*x),
+            &Int(x) => Int(x),
+            &Float(x) => Float(x),
+            &Bool(x) => Bool(x),
             String(x) => String(x.clone()),
             Null => Null,
-            Thunk(expr) => Thunk(*expr),
-            PrimOp(primop) => PrimOp(primop.clone()),
+            &Thunk(expr) => Thunk(expr),
+            &PrimOp(primop) => PrimOp(primop),
             PrimOpApp(primop) => PrimOpApp(primop.clone()),
-            Func(expr) => Func(*expr),
+            Func(expr) => Func(unsafe { expr.clone() }),
             FuncApp(func) => FuncApp(func.clone()),
         }
     }
 }
 
-impl<Ctx: EvalContext> Hash for Value<Ctx> {
+impl Hash for Value {
     fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
         use Value::*;
         std::mem::discriminant(self).hash(state);
@@ -98,7 +98,7 @@ impl<Ctx: EvalContext> Hash for Value<Ctx> {
     }
 }
 
-impl<Ctx: EvalContext> Value<Ctx> {
+impl Value {
     pub const INT: u64 = 0;
     pub const FLOAT: u64 = 1;
     pub const BOOL: u64 = 2;
@@ -130,7 +130,7 @@ impl<Ctx: EvalContext> Value<Ctx> {
     }
 }
 
-impl<Ctx: EvalContext> PartialEq for Value<Ctx> {
+impl PartialEq for Value {
     fn eq(&self, other: &Self) -> bool {
         use Value::*;
         match (self, other) {
@@ -141,27 +141,27 @@ impl<Ctx: EvalContext> PartialEq for Value<Ctx> {
     }
 }
 
-impl<Ctx: EvalContext> Eq for Value<Ctx> {}
+impl Eq for Value {}
 
 #[derive(IsVariant, TryUnwrap, Unwrap, Clone)]
-pub enum ValueAsRef<'v, Ctx: EvalContext> {
+pub enum ValueAsRef<'v> {
     Int(i64),
     Float(f64),
     Bool(bool),
     String(&'v String),
     Null,
     Thunk(usize),
-    AttrSet(&'v AttrSet<Ctx>),
-    List(&'v List<Ctx>),
+    AttrSet(&'v AttrSet),
+    List(&'v List),
     Catchable(&'v str),
-    PrimOp(&'v PrimOp<Ctx>),
-    PartialPrimOp(&'v PrimOpApp<Ctx>),
-    Func(ExprId),
-    PartialFunc(&'v FuncApp<Ctx>),
+    PrimOp(&'v PrimOp),
+    PartialPrimOp(&'v PrimOpApp),
+    Func(&'v ExprId),
+    PartialFunc(&'v FuncApp),
 }
 
-impl<Ctx: EvalContext> Value<Ctx> {
-    pub fn as_ref(&self) -> ValueAsRef<'_, Ctx> {
+impl Value {
+    pub fn as_ref(&self) -> ValueAsRef<'_> {
         use Value::*;
         use ValueAsRef as R;
         match self {
@@ -176,12 +176,12 @@ impl<Ctx: EvalContext> Value<Ctx> {
             Catchable(x) => R::Catchable(x),
             PrimOp(x) => R::PrimOp(x),
             PrimOpApp(x) => R::PartialPrimOp(x),
-            Func(x) => R::Func(*x),
+            Func(x) => R::Func(x),
             FuncApp(x) => R::PartialFunc(x),
         }
     }
 }
-impl<Ctx: EvalContext> Value<Ctx> {
+impl Value {
     pub fn ok(self) -> Result<Self> {
         Ok(self)
     }
@@ -213,32 +213,58 @@ impl<Ctx: EvalContext> Value<Ctx> {
         }
     }
 
-    pub fn call(&mut self, args: Vec<Self>, ctx: &mut Ctx) -> Result<()> {
+    pub fn call<Ctx: EvalContext>(&mut self, mut iter: impl Iterator<Item = Result<Value>> + ExactSizeIterator, ctx: &mut Ctx) -> Result<()> {
         use Value::*;
-        for arg in args.iter() {
-            if matches!(arg, Value::Catchable(_)) {
-                *self = arg.clone();
-                return Ok(());
-            }
-        }
         *self = match self {
-            PrimOp(func) => func.call(args, ctx),
-            PrimOpApp(func) => func.call(args, ctx),
-            FuncApp(func) => func.call(args, ctx),
-            &mut Func(expr) => {
-                let (args, ret) = ctx.with_args_env(args, |ctx| ctx.eval(expr));
-                let mut ret = ret?;
-                if let Value::Func(expr) = ret {
-                    let frame = ctx.pop_frame();
-                    ret = Value::FuncApp(self::FuncApp::new(expr, args, frame).into());
-                } else if let Value::FuncApp(func) = &mut ret {
-                    todo!();
-                    let func = Rc::make_mut(func);
+            &mut PrimOp(func) => {
+                if iter.len() > func.arity {
+                    todo!()
+                }
+                if func.arity > iter.len() {
+                    Value::PrimOpApp(Rc::new(self::PrimOpApp::new(
+                        func.name,
+                        func.arity - iter.len(),
+                        func.id,
+                        iter.collect::<Result<_>>()?,
+                    )))
+                    .ok()
+                } else {
+                    ctx.call_primop(func.id, iter.collect::<Result<_>>()?)
                 }
-                ret.ok()
             }
+            Func(expr) => {
+                let mut val;
+                let mut args = Vec::with_capacity(iter.len());
+                args.push(iter.next().unwrap()?);
+                let (ret_args, ret) = ctx.with_args_env(args, |ctx| ctx.eval(expr));
+                args = ret_args;
+                val = ret?;
+                loop {
+                    if !matches!(val, Value::Func(_) | Value::FuncApp(_)) {
+                        break;
+                    }
+                    let Some(arg) = iter.next() else {
+                        break;
+                    };
+                    args.push(arg?);
+                    if let Value::Func(expr) = val {
+                        let (ret_args, ret) = ctx.with_args_env(args, |ctx| ctx.eval(&expr));
+                        args = ret_args;
+                        val = ret?;
+                    } else if let Value::FuncApp(func) = val {
+                        let mut func = Rc::unwrap_or_clone(func);
+                        func.args.push(args.pop().unwrap());
+                        let (ret_args, ret) = ctx.with_args_env(func.args, |ctx| ctx.eval(&func.body));
+                        args = ret_args;
+                        val = ret?;
+                    }
+                }
+                val.ok()
+            }
+            PrimOpApp(func) => func.call(iter.collect::<Result<_>>()?, ctx),
+            FuncApp(func) => func.call(iter, ctx),
             Catchable(_) => return Ok(()),
-            other => todo!("{}", other.typename()),
+            _ => Err(Error::EvalError("attempt to call something which is not a function but ...".to_string()))
         }?;
         Ok(())
     }
@@ -310,22 +336,26 @@ impl<Ctx: EvalContext> Value<Ctx> {
 
     pub fn add(&mut self, other: Self) -> Result<()> {
         use Value::*;
-        replace_with_and_return(self, || abort(), |a| {
-            let val = match (a, other) {
-                (Int(a), Int(b)) => Int(a + b),
-                (Int(a), Float(b)) => Float(a as f64 + b),
-                (Float(a), Int(b)) => Float(a + b as f64),
-                (Float(a), Float(b)) => Float(a + b),
-                (String(mut a), String(b)) => {
-                    a.push_str(&b);
-                    String(a)
-                }
-                (a @ Value::Catchable(_), _) => a,
-                (_, x @ Value::Catchable(_)) => x,
-                _ => return (Err(Error::EvalError(format!(""))), Value::Null),
-            };
-            (Ok(()), val)
-        })
+        replace_with_and_return(
+            self,
+            || abort(),
+            |a| {
+                let val = match (a, other) {
+                    (Int(a), Int(b)) => Int(a + b),
+                    (Int(a), Float(b)) => Float(a as f64 + b),
+                    (Float(a), Int(b)) => Float(a + b as f64),
+                    (Float(a), Float(b)) => Float(a + b),
+                    (String(mut a), String(b)) => {
+                        a.push_str(&b);
+                        String(a)
+                    }
+                    (a @ Value::Catchable(_), _) => a,
+                    (_, x @ Value::Catchable(_)) => x,
+                    _ => return (Err(Error::EvalError(format!(""))), Value::Null),
+                };
+                (Ok(()), val)
+            },
+        )
     }
 
     pub fn mul(&mut self, other: Self) {
@@ -490,7 +520,7 @@ impl<Ctx: EvalContext> Value<Ctx> {
         self
     }
 
-    pub fn to_public(&self, ctx: &Ctx, seen: &mut HashSet<Value<Ctx>>) -> PubValue {
+    pub fn to_public(&self, seen: &mut HashSet<Value>) -> PubValue {
         use Value::*;
         if seen.contains(self) {
             return PubValue::Repeated;
@@ -498,11 +528,11 @@ impl<Ctx: EvalContext> Value<Ctx> {
         match self {
             AttrSet(attrs) => {
                 seen.insert(self.clone());
-                attrs.to_public(ctx, seen)
+                attrs.to_public(seen)
             }
             List(list) => {
                 seen.insert(self.clone());
-                list.to_public(ctx, seen)
+                list.to_public(seen)
             }
             Catchable(catchable) => PubValue::Catchable(catchable.clone().into()),
             Int(x) => PubValue::Const(Const::Int(*x)),
diff --git a/evaluator/nixjit_eval/src/value/primop.rs b/evaluator/nixjit_eval/src/value/primop.rs
index eed6f83..06faee3 100644
--- a/evaluator/nixjit_eval/src/value/primop.rs
+++ b/evaluator/nixjit_eval/src/value/primop.rs
@@ -3,67 +3,34 @@ use std::rc::Rc;
 use derive_more::Constructor;
 
 use nixjit_error::Result;
+use nixjit_ir::PrimOpId;
 
 use super::Value;
 use crate::EvalContext;
 
 #[derive(Debug, Clone, Constructor)]
-pub struct PrimOp<Ctx: EvalContext> {
+pub struct PrimOpApp {
     pub name: &'static str,
     arity: usize,
-    func: fn(Vec<Value<Ctx>>, &Ctx) -> Result<Value<Ctx>>,
+    id: PrimOpId,
+    args: Vec<Value>,
 }
 
-impl<Ctx: EvalContext> PrimOp<Ctx> {
-    pub fn call(&self, args: Vec<Value<Ctx>>, ctx: &Ctx) -> Result<Value<Ctx>> {
-        if args.len() > self.arity {
-            todo!()
-        }
-        if self.arity > args.len() {
-            Value::PrimOpApp(Rc::new(PrimOpApp {
-                name: self.name,
-                arity: self.arity - args.len(),
-                args,
-                func: self.func,
-            }))
-            .ok()
-        } else {
-            (self.func)(args, ctx)
-        }
-    }
-}
-
-#[derive(Debug)]
-pub struct PrimOpApp<Ctx: EvalContext> {
-    pub name: &'static str,
-    arity: usize,
-    args: Vec<Value<Ctx>>,
-    func: fn(Vec<Value<Ctx>>, &Ctx) -> Result<Value<Ctx>>,
-}
-
-impl<Ctx: EvalContext> Clone for PrimOpApp<Ctx> {
-    fn clone(&self) -> Self {
-        Self {
-            name: self.name,
-            arity: self.arity,
-            args: self.args.clone(),
-            func: self.func,
-        }
-    }
-}
-
-impl<Ctx: EvalContext> PrimOpApp<Ctx> {
-    pub fn call(self: &mut Rc<Self>, args: Vec<Value<Ctx>>, ctx: &Ctx) -> Result<Value<Ctx>> {
+impl PrimOpApp {
+    pub fn call(
+        self: &mut Rc<Self>,
+        args: Vec<Value>,
+        ctx: &mut impl EvalContext,
+    ) -> Result<Value> {
         if self.arity < args.len() {
             todo!()
         }
-        let func = self.func;
         let Some(ret) = ({
             let self_mut = Rc::make_mut(self);
             self_mut.arity -= args.len();
             self_mut.args.extend(args);
             if self_mut.arity == 0 {
-                Some(func(std::mem::take(&mut self_mut.args), ctx))
+                Some(ctx.call_primop(self_mut.id, std::mem::take(&mut self_mut.args)))
             } else {
                 None
             }
diff --git a/evaluator/nixjit_hir/src/downgrade.rs b/evaluator/nixjit_hir/src/downgrade.rs
index ab92ef3..a2fcd19 100644
--- a/evaluator/nixjit_hir/src/downgrade.rs
+++ b/evaluator/nixjit_hir/src/downgrade.rs
@@ -256,40 +256,6 @@ impl<Ctx: DowngradeContext> Downgrade<Ctx> for ast::Lambda {
         let param = downgrade_param(self.param().unwrap(), ctx)?;
         let mut body = self.body().unwrap().downgrade(ctx)?;
 
-        // Desugar pattern matching in function arguments into a `let` expression.
-        // For example, `({ a, b ? 2 }): a + b` is desugared into:
-        // `arg: let a = arg.a; b = arg.b or 2; in a + b`
-        if let Param::Formals { formals, alias, .. } = &param {
-            // `Arg` represents the raw argument (the attribute set) passed to the function.
-            let arg = ctx.new_expr(Hir::Arg(Arg));
-            let mut bindings: HashMap<_, _> = formals
-                .iter()
-                .map(|&(ref k, default)| {
-                    // For each formal parameter, create a `Select` expression to extract it from the argument set.
-                    (
-                        k.clone(),
-                        ctx.new_expr(
-                            Select {
-                                expr: arg,
-                                attrpath: vec![Attr::Str(k.clone())],
-                                default,
-                            }
-                            .to_hir(),
-                        ),
-                    )
-                })
-                .collect();
-            // If there's an alias (`... }@alias`), bind the alias name to the raw argument set.
-            if let Some(alias) = alias {
-                bindings.insert(
-                    alias.clone(),
-                    ctx.new_expr(Var { sym: alias.clone() }.to_hir()),
-                );
-            }
-            // Wrap the original function body in the new `let` expression.
-            let let_ = Let { bindings, body };
-            body = ctx.new_expr(let_.to_hir());
-        }
         let ident;
         let required;
         let allowed;
@@ -304,22 +270,55 @@ impl<Ctx: DowngradeContext> Downgrade<Ctx> for ast::Lambda {
                 ellipsis,
                 alias,
             } => {
-                ident = alias;
+                ident = alias.clone();
                 required = Some(
                     formals
                         .iter()
-                        .cloned()
                         .filter(|(_, default)| default.is_none())
-                        .map(|(k, _)| k)
+                        .map(|(k, _)| k.clone())
                         .collect(),
                 );
                 allowed = if ellipsis {
                     None
                 } else {
-                    Some(formals.into_iter().map(|(k, _)| k).collect())
+                    Some(formals.iter().map(|(k, _)| k.clone()).collect())
                 };
+
+                // Desugar pattern matching in function arguments into a `let` expression.
+                // For example, `({ a, b ? 2 }): a + b` is desugared into:
+                // `arg: let a = arg.a; b = arg.b or 2; in a + b`
+                let mut bindings: HashMap<_, _> = formals
+                    .into_iter()
+                    .map(|(k, default)| {
+                        // For each formal parameter, create a `Select` expression to extract it from the argument set.
+                        // `Arg` represents the raw argument (the attribute set) passed to the function.
+                        let arg = ctx.new_expr(Hir::Arg(Arg));
+                        (
+                            k.clone(),
+                            ctx.new_expr(
+                                Select {
+                                    expr: arg,
+                                    attrpath: vec![Attr::Str(k.clone())],
+                                    default,
+                                }
+                                .to_hir(),
+                            ),
+                        )
+                    })
+                    .collect();
+                // If there's an alias (`... }@alias`), bind the alias name to the raw argument set.
+                if let Some(alias) = alias {
+                    bindings.insert(
+                        alias.clone(),
+                        ctx.new_expr(Var { sym: alias.clone() }.to_hir()),
+                    );
+                }
+                // Wrap the original function body in the new `let` expression.
+                let let_ = Let { bindings, body };
+                body = ctx.new_expr(let_.to_hir());
             }
         }
+
         let param = ir::Param {
             ident,
             required,
diff --git a/evaluator/nixjit_hir/src/lib.rs b/evaluator/nixjit_hir/src/lib.rs
index cf8f6c9..d42174f 100644
--- a/evaluator/nixjit_hir/src/lib.rs
+++ b/evaluator/nixjit_hir/src/lib.rs
@@ -40,7 +40,7 @@ pub trait DowngradeContext {
     fn with_expr<T>(&self, id: ExprId, f: impl FnOnce(&Hir, &Self) -> T) -> T;
 
     /// Provides temporary mutable access to an expression.
-    fn with_expr_mut<T>(&mut self, id: ExprId, f: impl FnOnce(&mut Hir, &mut Self) -> T) -> T;
+    fn with_expr_mut<T>(&mut self, id: &ExprId, f: impl FnOnce(&mut Hir, &mut Self) -> T) -> T;
 }
 
 ir! {
@@ -123,7 +123,7 @@ impl Attrs for AttrSet {
             match attr {
                 Attr::Str(ident) => {
                     // If the next attribute is a static string.
-                    if let Some(&id) = self.stcs.get(&ident) {
+                    if let Some(id) = self.stcs.get(&ident) {
                         // If a sub-attrset already exists, recurse into it.
                         ctx.with_expr_mut(id, |expr, ctx| {
                             expr.as_mut()
@@ -186,7 +186,7 @@ impl Attrs for AttrSet {
     }
 }
 
-#[derive(Clone, Debug)]
+#[derive(Debug)]
 enum Param {
     /// A simple parameter, e.g., `x: ...`.
     Ident(String),
diff --git a/evaluator/nixjit_hir/src/utils.rs b/evaluator/nixjit_hir/src/utils.rs
index c5004f9..4156d5a 100644
--- a/evaluator/nixjit_hir/src/utils.rs
+++ b/evaluator/nixjit_hir/src/utils.rs
@@ -125,13 +125,13 @@ pub fn downgrade_inherit(
                 ));
             }
         };
-        let expr = from.map_or_else(
+        let expr = from.as_ref().map_or_else(
             // If `from` is None, `inherit foo;` becomes `foo = foo;`.
             || Var { sym: ident.clone() }.to_hir(),
             // If `from` is Some, `inherit (from) foo;` becomes `foo = from.foo;`.
             |expr| {
                 Select {
-                    expr,
+                    expr: unsafe { expr.clone() },
                     attrpath: vec![Attr::Str(ident.clone())],
                     default: None,
                 }
diff --git a/evaluator/nixjit_ir/src/lib.rs b/evaluator/nixjit_ir/src/lib.rs
index dfc45c4..529001f 100644
--- a/evaluator/nixjit_ir/src/lib.rs
+++ b/evaluator/nixjit_ir/src/lib.rs
@@ -3,7 +3,7 @@
 //! The IR provides a simplified, language-agnostic representation of Nix expressions,
 //! serving as a bridge between the high-level representation (HIR) and the low-level
 //! representation (LIR). It defines the fundamental building blocks like expression IDs,
-//! function IDs, and structures for various expression types (e.g., binary operations,
+//! argument indexes, and structures for various expression types (e.g., binary operations,
 //! attribute sets, function calls).
 //!
 //! These structures are designed to be generic and reusable across different stages of
@@ -18,35 +18,40 @@ use nixjit_value::Const as PubConst;
 
 /// A type-safe wrapper for an index into an expression table.
 #[repr(transparent)]
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+#[derive(Debug, PartialEq, Eq, Hash)]
 pub struct ExprId(usize);
 
-impl From<usize> for ExprId {
-    fn from(id: usize) -> Self {
-        ExprId(id)
+impl ExprId {
+    #[inline(always)]
+    pub unsafe fn clone(&self) -> Self {
+        Self(self.0)
+    }
+
+    #[inline(always)]
+    pub unsafe fn raw(self) -> usize {
+        self.0
+    }
+
+    #[inline(always)]
+    pub unsafe fn from(id: usize) -> Self {
+        Self(id)
     }
 }
 
-impl From<ExprId> for usize {
-    fn from(id: ExprId) -> Self {
-        id.0
-    }
-}
-
-/// A type-safe wrapper for an index into a function table.
+/// A type-safe wrapper for an index into a primop (builtin function) table.
 #[repr(transparent)]
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
-pub struct FuncId(usize);
+pub struct PrimOpId(usize);
 
-impl From<usize> for FuncId {
-    fn from(id: usize) -> Self {
-        FuncId(id)
+impl PrimOpId {
+    #[inline(always)]
+    pub unsafe fn raw(self) -> usize {
+        self.0
     }
-}
 
-impl From<FuncId> for usize {
-    fn from(id: FuncId) -> Self {
-        id.0
+    #[inline(always)]
+    pub unsafe fn from(id: usize) -> Self {
+        Self(id)
     }
 }
 
@@ -55,15 +60,15 @@ impl From<FuncId> for usize {
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub struct ArgIdx(usize);
 
-impl From<usize> for ArgIdx {
-    fn from(id: usize) -> Self {
-        ArgIdx(id)
+impl ArgIdx {
+    #[inline(always)]
+    pub unsafe fn raw(self) -> usize {
+        self.0
     }
-}
 
-impl From<ArgIdx> for usize {
-    fn from(id: ArgIdx) -> Self {
-        id.0
+    #[inline(always)]
+    pub unsafe fn from(idx: usize) -> Self {
+        Self(idx)
     }
 }
 
@@ -79,7 +84,7 @@ pub struct AttrSet {
 }
 
 /// Represents a key in an attribute path.
-#[derive(Clone, Debug, TryUnwrap)]
+#[derive(Debug, TryUnwrap)]
 pub enum Attr {
     /// A dynamic attribute key, which is an expression that must evaluate to a string.
     Dynamic(ExprId),
@@ -234,6 +239,14 @@ pub struct Call {
     pub args: Vec<ExprId>,
 }
 
+// Represents a primitive operation (builtin function)
+#[derive(Debug, Clone, Copy)]
+pub struct PrimOp {
+    pub name: &'static str,
+    pub id: PrimOpId,
+    pub arity: usize,
+}
+
 /// Represents a `with` expression.
 #[derive(Debug)]
 pub struct With {
diff --git a/evaluator/nixjit_jit/src/compile.rs b/evaluator/nixjit_jit/src/compile.rs
index a6b6a93..a41c678 100644
--- a/evaluator/nixjit_jit/src/compile.rs
+++ b/evaluator/nixjit_jit/src/compile.rs
@@ -88,10 +88,10 @@ impl<Ctx: JITContext> JITCompile<Ctx> for BinOp {
                 let float_block = ctx.builder.create_block();
                 let float_check_block = ctx.builder.create_block();
 
-                let is_int =
-                    ctx.builder
-                        .ins()
-                        .icmp_imm(IntCC::Equal, lhs_tag, Value::<Ctx>::INT as i64);
+                let is_int = ctx
+                    .builder
+                    .ins()
+                    .icmp_imm(IntCC::Equal, lhs_tag, Value::INT as i64);
                 ctx.builder
                     .ins()
                     .brif(is_int, int_block, [], float_check_block, []);
@@ -109,7 +109,7 @@ impl<Ctx: JITContext> JITCompile<Ctx> for BinOp {
                 let is_float =
                     ctx.builder
                         .ins()
-                        .icmp_imm(IntCC::Equal, lhs_tag, Value::<Ctx>::FLOAT as i64);
+                        .icmp_imm(IntCC::Equal, lhs_tag, Value::FLOAT as i64);
                 ctx.builder
                     .ins()
                     .brif(is_float, float_block, [], default_block, []);
@@ -141,10 +141,10 @@ impl<Ctx: JITContext> JITCompile<Ctx> for BinOp {
                 let float_block = ctx.builder.create_block();
                 let float_check_block = ctx.builder.create_block();
 
-                let is_int =
-                    ctx.builder
-                        .ins()
-                        .icmp_imm(IntCC::Equal, lhs_tag, Value::<Ctx>::INT as i64);
+                let is_int = ctx
+                    .builder
+                    .ins()
+                    .icmp_imm(IntCC::Equal, lhs_tag, Value::INT as i64);
                 ctx.builder
                     .ins()
                     .brif(is_int, int_block, [], float_check_block, []);
@@ -162,7 +162,7 @@ impl<Ctx: JITContext> JITCompile<Ctx> for BinOp {
                 let is_float =
                     ctx.builder
                         .ins()
-                        .icmp_imm(IntCC::Equal, lhs_tag, Value::<Ctx>::FLOAT as i64);
+                        .icmp_imm(IntCC::Equal, lhs_tag, Value::FLOAT as i64);
                 ctx.builder
                     .ins()
                     .brif(is_float, float_block, [], default_block, []);
@@ -194,10 +194,10 @@ impl<Ctx: JITContext> JITCompile<Ctx> for BinOp {
                 let float_block = ctx.builder.create_block();
                 let float_check_block = ctx.builder.create_block();
 
-                let is_int =
-                    ctx.builder
-                        .ins()
-                        .icmp_imm(IntCC::Equal, lhs_tag, Value::<Ctx>::INT as i64);
+                let is_int = ctx
+                    .builder
+                    .ins()
+                    .icmp_imm(IntCC::Equal, lhs_tag, Value::INT as i64);
                 ctx.builder
                     .ins()
                     .brif(is_int, int_block, [], float_check_block, []);
@@ -215,7 +215,7 @@ impl<Ctx: JITContext> JITCompile<Ctx> for BinOp {
                 let is_float =
                     ctx.builder
                         .ins()
-                        .icmp_imm(IntCC::Equal, lhs_tag, Value::<Ctx>::FLOAT as i64);
+                        .icmp_imm(IntCC::Equal, lhs_tag, Value::FLOAT as i64);
                 ctx.builder
                     .ins()
                     .brif(is_float, float_block, [], default_block, []);
@@ -245,10 +245,10 @@ impl<Ctx: JITContext> JITCompile<Ctx> for BinOp {
                 let bool_block = ctx.builder.create_block();
                 let non_bool_block = ctx.builder.create_block();
 
-                let is_bool =
-                    ctx.builder
-                        .ins()
-                        .icmp_imm(IntCC::Equal, lhs_tag, Value::<Ctx>::BOOL as i64);
+                let is_bool = ctx
+                    .builder
+                    .ins()
+                    .icmp_imm(IntCC::Equal, lhs_tag, Value::BOOL as i64);
                 ctx.builder
                     .ins()
                     .brif(is_bool, bool_block, [], non_bool_block, []);
@@ -275,10 +275,10 @@ impl<Ctx: JITContext> JITCompile<Ctx> for BinOp {
                 let bool_block = ctx.builder.create_block();
                 let non_bool_block = ctx.builder.create_block();
 
-                let is_bool =
-                    ctx.builder
-                        .ins()
-                        .icmp_imm(IntCC::Equal, lhs_tag, Value::<Ctx>::BOOL as i64);
+                let is_bool = ctx
+                    .builder
+                    .ins()
+                    .icmp_imm(IntCC::Equal, lhs_tag, Value::BOOL as i64);
                 ctx.builder
                     .ins()
                     .brif(is_bool, bool_block, [], non_bool_block, []);
@@ -378,10 +378,10 @@ impl<Ctx: JITContext> JITCompile<Ctx> for If {
         let judge_block = ctx.builder.create_block();
         let slot = ctx.alloca();
 
-        let is_bool =
-            ctx.builder
-                .ins()
-                .icmp_imm(IntCC::Equal, cond_type, Value::<Ctx>::BOOL as i64);
+        let is_bool = ctx
+            .builder
+            .ins()
+            .icmp_imm(IntCC::Equal, cond_type, Value::BOOL as i64);
         ctx.builder
             .ins()
             .brif(is_bool, judge_block, [], error_block, []);
@@ -480,37 +480,25 @@ impl<Ctx: JITContext> JITCompile<Ctx> for Const {
         let slot = ctx.alloca();
         match self.val {
             Bool(x) => {
-                let tag = ctx
-                    .builder
-                    .ins()
-                    .iconst(types::I64, Value::<Ctx>::BOOL as i64);
+                let tag = ctx.builder.ins().iconst(types::I64, Value::BOOL as i64);
                 let val = ctx.builder.ins().iconst(types::I64, x as i64);
                 ctx.builder.ins().stack_store(tag, slot, 0);
                 ctx.builder.ins().stack_store(val, slot, 8);
             }
             Int(x) => {
-                let tag = ctx
-                    .builder
-                    .ins()
-                    .iconst(types::I64, Value::<Ctx>::INT as i64);
+                let tag = ctx.builder.ins().iconst(types::I64, Value::INT as i64);
                 let val = ctx.builder.ins().iconst(types::I64, x);
                 ctx.builder.ins().stack_store(tag, slot, 0);
                 ctx.builder.ins().stack_store(val, slot, 8);
             }
             Float(x) => {
-                let tag = ctx
-                    .builder
-                    .ins()
-                    .iconst(types::I64, Value::<Ctx>::FLOAT as i64);
+                let tag = ctx.builder.ins().iconst(types::I64, Value::FLOAT as i64);
                 let val = ctx.builder.ins().f64const(x);
                 ctx.builder.ins().stack_store(tag, slot, 0);
                 ctx.builder.ins().stack_store(val, slot, 8);
             }
             Null => {
-                let tag = ctx
-                    .builder
-                    .ins()
-                    .iconst(types::I64, Value::<Ctx>::NULL as i64);
+                let tag = ctx.builder.ins().iconst(types::I64, Value::NULL as i64);
                 ctx.builder.ins().stack_store(tag, slot, 0);
             }
         }
diff --git a/evaluator/nixjit_jit/src/helpers.rs b/evaluator/nixjit_jit/src/helpers.rs
index d628fc1..4512823 100644
--- a/evaluator/nixjit_jit/src/helpers.rs
+++ b/evaluator/nixjit_jit/src/helpers.rs
@@ -11,21 +11,21 @@ use nixjit_eval::{AttrSet, EvalContext, List, Value};
 use super::JITContext;
 
 pub extern "C" fn helper_call<Ctx: JITContext>(
-    func: &mut Value<Ctx>,
-    args_ptr: *mut Value<Ctx>,
+    func: &mut Value,
+    args_ptr: *mut Value,
     args_len: usize,
     ctx: &mut Ctx,
 ) {
     // TODO: Error Handling
     let args = core::ptr::slice_from_raw_parts_mut(args_ptr, args_len);
     let args = unsafe { Box::from_raw(args) };
-    func.call(args.into_iter().collect(), ctx).unwrap();
+    func.call(args.into_iter().map(Ok), ctx).unwrap();
 }
 
 pub extern "C" fn helper_lookup_stack<Ctx: JITContext>(
     ctx: &Ctx,
     offset: usize,
-    ret: &mut MaybeUninit<Value<Ctx>>,
+    ret: &mut MaybeUninit<Value>,
 ) {
     ret.write(ctx.lookup_stack(offset).clone());
 }
@@ -33,7 +33,7 @@ pub extern "C" fn helper_lookup_stack<Ctx: JITContext>(
 pub extern "C" fn helper_lookup_arg<Ctx: JITContext>(
     ctx: &Ctx,
     offset: usize,
-    ret: &mut MaybeUninit<Value<Ctx>>,
+    ret: &mut MaybeUninit<Value>,
 ) {
     ret.write(JITContext::lookup_arg(ctx, offset).clone());
 }
@@ -42,7 +42,7 @@ pub extern "C" fn helper_lookup<Ctx: JITContext>(
     ctx: &Ctx,
     sym_ptr: *const u8,
     sym_len: usize,
-    ret: &mut MaybeUninit<Value<Ctx>>,
+    ret: &mut MaybeUninit<Value>,
 ) {
     // TODO: Error Handling
     unsafe {
@@ -57,8 +57,8 @@ pub extern "C" fn helper_lookup<Ctx: JITContext>(
 }
 
 pub extern "C" fn helper_select<Ctx: JITContext>(
-    val: &mut Value<Ctx>,
-    path_ptr: *mut Value<Ctx>,
+    val: &mut Value,
+    path_ptr: *mut Value,
     path_len: usize,
 ) {
     let path = core::ptr::slice_from_raw_parts_mut(path_ptr, path_len);
@@ -71,10 +71,10 @@ pub extern "C" fn helper_select<Ctx: JITContext>(
 }
 
 pub extern "C" fn helper_select_with_default<Ctx: JITContext>(
-    val: &mut Value<Ctx>,
-    path_ptr: *mut Value<Ctx>,
+    val: &mut Value,
+    path_ptr: *mut Value,
     path_len: usize,
-    default: NonNull<Value<Ctx>>,
+    default: NonNull<Value>,
 ) {
     let path = core::ptr::slice_from_raw_parts_mut(path_ptr, path_len);
     let path = unsafe { Box::from_raw(path) };
@@ -88,14 +88,14 @@ pub extern "C" fn helper_select_with_default<Ctx: JITContext>(
     .unwrap();
 }
 
-pub extern "C" fn helper_eq<Ctx: JITContext>(lhs: &mut Value<Ctx>, rhs: &Value<Ctx>) {
+pub extern "C" fn helper_eq<Ctx: JITContext>(lhs: &mut Value, rhs: &Value) {
     lhs.eq(rhs);
 }
 
 pub unsafe extern "C" fn helper_create_string<Ctx: JITContext>(
     ptr: *const u8,
     len: usize,
-    ret: &mut MaybeUninit<Value<Ctx>>,
+    ret: &mut MaybeUninit<Value>,
 ) {
     unsafe {
         ret.write(Value::String(
@@ -105,9 +105,9 @@ pub unsafe extern "C" fn helper_create_string<Ctx: JITContext>(
 }
 
 pub unsafe extern "C" fn helper_create_list<Ctx: JITContext>(
-    ptr: *mut Value<Ctx>,
+    ptr: *mut Value,
     len: usize,
-    ret: &mut MaybeUninit<Value<Ctx>>,
+    ret: &mut MaybeUninit<Value>,
 ) {
     unsafe {
         ret.write(Value::List(
@@ -117,16 +117,16 @@ pub unsafe extern "C" fn helper_create_list<Ctx: JITContext>(
 }
 
 pub unsafe extern "C" fn helper_create_attrs<Ctx: JITContext>(
-    ret: &mut MaybeUninit<HashMap<String, Value<Ctx>>>,
+    ret: &mut MaybeUninit<HashMap<String, Value>>,
 ) {
     ret.write(HashMap::new());
 }
 
 pub unsafe extern "C" fn helper_push_attr<Ctx: JITContext>(
-    attrs: &mut HashMap<String, Value<Ctx>>,
+    attrs: &mut HashMap<String, Value>,
     sym_ptr: *const u8,
     sym_len: usize,
-    val: NonNull<Value<Ctx>>,
+    val: NonNull<Value>,
 ) {
     unsafe {
         attrs.insert(
@@ -137,8 +137,8 @@ pub unsafe extern "C" fn helper_push_attr<Ctx: JITContext>(
 }
 
 pub unsafe extern "C" fn helper_finalize_attrs<Ctx: JITContext>(
-    attrs: NonNull<HashMap<String, Value<Ctx>>>,
-    ret: &mut MaybeUninit<Value<Ctx>>,
+    attrs: NonNull<HashMap<String, Value>>,
+    ret: &mut MaybeUninit<Value>,
 ) {
     ret.write(Value::AttrSet(
         AttrSet::from(unsafe { attrs.read() }).into(),
@@ -147,7 +147,7 @@ pub unsafe extern "C" fn helper_finalize_attrs<Ctx: JITContext>(
 
 pub unsafe extern "C" fn helper_enter_with<Ctx: JITContext>(
     ctx: &mut Ctx,
-    namespace: NonNull<Value<Ctx>>,
+    namespace: NonNull<Value>,
 ) {
     ctx.enter_with(unsafe { namespace.read() }.unwrap_attr_set().into_inner());
 }
@@ -157,9 +157,9 @@ pub unsafe extern "C" fn helper_exit_with<Ctx: JITContext>(ctx: &mut Ctx) {
 }
 
 pub unsafe extern "C" fn helper_alloc_array<Ctx: JITContext>(len: usize) -> *mut u8 {
-    unsafe { alloc(Layout::array::<Value<Ctx>>(len).unwrap()) }
+    unsafe { alloc(Layout::array::<Value>(len).unwrap()) }
 }
 
-pub extern "C" fn helper_dbg<Ctx: JITContext>(value: &Value<Ctx>) {
+pub extern "C" fn helper_dbg<Ctx: JITContext>(value: &Value) {
     println!("{value:?}")
 }
diff --git a/evaluator/nixjit_jit/src/lib.rs b/evaluator/nixjit_jit/src/lib.rs
index e1ed25e..f80b689 100644
--- a/evaluator/nixjit_jit/src/lib.rs
+++ b/evaluator/nixjit_jit/src/lib.rs
@@ -19,13 +19,13 @@ pub use compile::JITCompile;
 use helpers::*;
 
 pub trait JITContext: EvalContext + Sized {
-    fn lookup_stack(&self, offset: usize) -> &Value<Self>;
-    fn lookup_arg(&self, offset: usize) -> &Value<Self>;
-    fn enter_with(&mut self, namespace: Rc<HashMap<String, Value<Self>>>);
+    fn lookup_stack(&self, offset: usize) -> &Value;
+    fn lookup_arg(&self, offset: usize) -> &Value;
+    fn enter_with(&mut self, namespace: Rc<HashMap<String, Value>>);
     fn exit_with(&mut self);
 }
 
-type F<Ctx: JITContext> = unsafe extern "C" fn(*const Ctx, *mut Value<Ctx>);
+type F<Ctx> = unsafe extern "C" fn(*const Ctx, *mut Value);
 
 pub struct JITFunc<Ctx: JITContext> {
     func: F<Ctx>,
diff --git a/evaluator/nixjit_lir/src/lib.rs b/evaluator/nixjit_lir/src/lib.rs
index 534cfa0..2209c91 100644
--- a/evaluator/nixjit_lir/src/lib.rs
+++ b/evaluator/nixjit_lir/src/lib.rs
@@ -24,12 +24,16 @@ ir! {
     Str,
     Var,
     Path,
+    PrimOp,
     ExprRef(ExprId),
     FuncRef(ExprId),
     ArgRef(ArgIdx),
 }
 
-#[derive(Debug, Clone, Copy)]
+#[derive(Debug)]
+pub struct Builtins;
+
+#[derive(Debug)]
 pub enum LookupResult {
     Expr(ExprId),
     Arg(ArgIdx),
@@ -38,21 +42,17 @@ pub enum LookupResult {
 }
 
 pub trait ResolveContext {
-    fn new_dep(&mut self, expr: ExprId, dep: ExprId);
-    fn new_func(&mut self, body: ExprId, param: Param);
-    fn resolve(&mut self, expr: ExprId) -> Result<()>;
+    fn new_dep(&mut self, expr: &ExprId, dep: ExprId);
+    fn new_func(&mut self, body: &ExprId, param: Param);
+    fn resolve(&mut self, expr: &ExprId) -> Result<()>;
     fn lookup(&self, name: &str) -> LookupResult;
     fn with_with_env<T>(&mut self, f: impl FnOnce(&mut Self) -> T) -> (bool, T);
     fn with_let_env<'a, T>(
         &mut self,
-        bindings: impl IntoIterator<Item = (&'a String, &'a ExprId)>,
-        f: impl FnOnce(&mut Self) -> T,
-    ) -> T;
-    fn with_param_env<'a, T>(
-        &mut self,
-        ident: Option<&'a str>,
+        bindings: impl Iterator<Item = (&'a String, &'a ExprId)>,
         f: impl FnOnce(&mut Self) -> T,
     ) -> T;
+    fn with_param_env<T>(&mut self, ident: Option<String>, f: impl FnOnce(&mut Self) -> T) -> T;
 }
 
 pub trait Resolve<Ctx: ResolveContext> {
@@ -80,7 +80,7 @@ impl<Ctx: ResolveContext> Resolve<Ctx> for hir::Hir {
             Var(x) => x.resolve(ctx),
             Path(x) => x.resolve(ctx),
             Let(x) => x.resolve(ctx),
-            Arg(_) => todo!(),
+            Arg(_) => unsafe { Ok(Lir::ArgRef(ArgIdx::from(0))) },
         }
     }
 }
@@ -90,10 +90,10 @@ impl<Ctx: ResolveContext> Resolve<Ctx> for AttrSet {
         if self.rec {
             todo!()
         } else {
-            for (_, &v) in self.stcs.iter() {
+            for (_, v) in self.stcs.iter() {
                 ctx.resolve(v)?;
             }
-            for &(k, v) in self.dyns.iter() {
+            for (k, v) in self.dyns.iter() {
                 ctx.resolve(k)?;
                 ctx.resolve(v)?;
             }
@@ -104,7 +104,7 @@ impl<Ctx: ResolveContext> Resolve<Ctx> for AttrSet {
 
 impl<Ctx: ResolveContext> Resolve<Ctx> for List {
     fn resolve(self, ctx: &mut Ctx) -> Result<Lir> {
-        for &item in self.items.iter() {
+        for item in self.items.iter() {
             ctx.resolve(item)?;
         }
         Ok(self.to_lir())
@@ -113,10 +113,10 @@ impl<Ctx: ResolveContext> Resolve<Ctx> for List {
 
 impl<Ctx: ResolveContext> Resolve<Ctx> for HasAttr {
     fn resolve(self, ctx: &mut Ctx) -> Result<Lir> {
-        ctx.resolve(self.lhs)?;
+        ctx.resolve(&self.lhs)?;
         for attr in self.rhs.iter() {
-            if let &Attr::Dynamic(expr) = attr {
-                ctx.resolve(expr)?;
+            if let Attr::Dynamic(expr) = attr {
+                ctx.resolve(&expr)?;
             }
         }
         Ok(self.to_lir())
@@ -125,28 +125,28 @@ impl<Ctx: ResolveContext> Resolve<Ctx> for HasAttr {
 
 impl<Ctx: ResolveContext> Resolve<Ctx> for BinOp {
     fn resolve(self, ctx: &mut Ctx) -> Result<Lir> {
-        ctx.resolve(self.lhs)?;
-        ctx.resolve(self.rhs)?;
+        ctx.resolve(&self.lhs)?;
+        ctx.resolve(&self.rhs)?;
         Ok(self.to_lir())
     }
 }
 
 impl<Ctx: ResolveContext> Resolve<Ctx> for UnOp {
     fn resolve(self, ctx: &mut Ctx) -> Result<Lir> {
-        ctx.resolve(self.rhs)?;
+        ctx.resolve(&self.rhs)?;
         Ok(self.to_lir())
     }
 }
 
 impl<Ctx: ResolveContext> Resolve<Ctx> for Select {
     fn resolve(self, ctx: &mut Ctx) -> Result<Lir> {
-        ctx.resolve(self.expr)?;
+        ctx.resolve(&self.expr)?;
         for attr in self.attrpath.iter() {
-            if let &Attr::Dynamic(expr) = attr {
-                ctx.resolve(expr)?;
+            if let Attr::Dynamic(expr) = attr {
+                ctx.resolve(&expr)?;
             }
         }
-        if let Some(expr) = self.default {
+        if let Some(ref expr) = self.default {
             ctx.resolve(expr)?;
         }
         Ok(self.to_lir())
@@ -155,25 +155,25 @@ impl<Ctx: ResolveContext> Resolve<Ctx> for Select {
 
 impl<Ctx: ResolveContext> Resolve<Ctx> for If {
     fn resolve(self, ctx: &mut Ctx) -> Result<Lir> {
-        ctx.resolve(self.cond)?;
-        ctx.resolve(self.consq)?;
-        ctx.resolve(self.alter)?;
+        ctx.resolve(&self.cond)?;
+        ctx.resolve(&self.consq)?;
+        ctx.resolve(&self.alter)?;
         Ok(self.to_lir())
     }
 }
 
 impl<Ctx: ResolveContext> Resolve<Ctx> for Func {
     fn resolve(self, ctx: &mut Ctx) -> Result<Lir> {
-        ctx.with_param_env(self.param.ident.as_deref(), |ctx| ctx.resolve(self.body))?;
-        ctx.new_func(self.body, self.param);
+        ctx.with_param_env(self.param.ident.clone(), |ctx| ctx.resolve(&self.body))?;
+        ctx.new_func(&self.body, self.param);
         Ok(Lir::FuncRef(self.body))
     }
 }
 
 impl<Ctx: ResolveContext> Resolve<Ctx> for Call {
     fn resolve(self, ctx: &mut Ctx) -> Result<Lir> {
-        ctx.resolve(self.func)?;
-        for &arg in self.args.iter() {
+        ctx.resolve(&self.func)?;
+        for arg in self.args.iter() {
             ctx.resolve(arg)?;
         }
         Ok(self.to_lir())
@@ -182,8 +182,8 @@ impl<Ctx: ResolveContext> Resolve<Ctx> for Call {
 
 impl<Ctx: ResolveContext> Resolve<Ctx> for With {
     fn resolve(self, ctx: &mut Ctx) -> Result<Lir> {
-        ctx.resolve(self.namespace)?;
-        let (env_used, res) = ctx.with_with_env(|ctx| ctx.resolve(self.expr));
+        ctx.resolve(&self.namespace)?;
+        let (env_used, res) = ctx.with_with_env(|ctx| ctx.resolve(&self.expr));
         res?;
         if env_used {
             Ok(self.to_lir())
@@ -195,15 +195,15 @@ impl<Ctx: ResolveContext> Resolve<Ctx> for With {
 
 impl<Ctx: ResolveContext> Resolve<Ctx> for Assert {
     fn resolve(self, ctx: &mut Ctx) -> Result<Lir> {
-        ctx.resolve(self.assertion)?;
-        ctx.resolve(self.expr)?;
+        ctx.resolve(&self.assertion)?;
+        ctx.resolve(&self.expr)?;
         Ok(self.to_lir())
     }
 }
 
 impl<Ctx: ResolveContext> Resolve<Ctx> for ConcatStrings {
     fn resolve(self, ctx: &mut Ctx) -> Result<Lir> {
-        for &part in self.parts.iter() {
+        for part in self.parts.iter() {
             ctx.resolve(part)?;
         }
         Ok(self.to_lir())
@@ -227,7 +227,7 @@ impl<Ctx: ResolveContext> Resolve<Ctx> for Var {
 
 impl<Ctx: ResolveContext> Resolve<Ctx> for Path {
     fn resolve(self, ctx: &mut Ctx) -> Result<Lir> {
-        ctx.resolve(self.expr)?;
+        ctx.resolve(&self.expr)?;
         Ok(self.to_lir())
     }
 }
@@ -235,10 +235,10 @@ impl<Ctx: ResolveContext> Resolve<Ctx> for Path {
 impl<Ctx: ResolveContext> Resolve<Ctx> for hir::Let {
     fn resolve(self, ctx: &mut Ctx) -> Result<Lir> {
         ctx.with_let_env(self.bindings.iter(), |ctx| {
-            for &id in self.bindings.values() {
+            for id in self.bindings.values() {
                 ctx.resolve(id)?;
             }
-            ctx.resolve(self.body)
+            ctx.resolve(&self.body)
         })?;
         Ok(Lir::ExprRef(self.body))
     }
diff --git a/evaluator/nixjit_macros/src/builtins.rs b/evaluator/nixjit_macros/src/builtins.rs
index 983d4ee..a9079b4 100644
--- a/evaluator/nixjit_macros/src/builtins.rs
+++ b/evaluator/nixjit_macros/src/builtins.rs
@@ -1,16 +1,17 @@
 use convert_case::{Case, Casing};
 use proc_macro::TokenStream;
 use proc_macro2::Span;
-use quote::{format_ident, quote, ToTokens};
+use quote::{ToTokens, format_ident, quote};
 use syn::{
-    parse_macro_input, FnArg, Item, ItemConst, ItemFn, ItemMod, Pat, PatType, Type,
-    Visibility,
+    FnArg, Item, ItemFn, ItemMod, Pat, PatType, Type, Visibility, parse_macro_input,
 };
 
 pub fn builtins_impl(input: TokenStream) -> TokenStream {
     let item_mod = parse_macro_input!(input as ItemMod);
+    let mod_name = &item_mod.ident;
+    let visibility = &item_mod.vis;
 
-    let (_brace, items) = match item_mod.content.clone() {
+    let (_brace, items) = match item_mod.content {
         Some(content) => content,
         None => {
             return syn::Error::new_spanned(
@@ -23,63 +24,76 @@ pub fn builtins_impl(input: TokenStream) -> TokenStream {
     };
 
     let mut pub_item_mod: Vec<proc_macro2::TokenStream> = Vec::new();
-    let mut const_inserters = Vec::new();
-    let mut global_inserters = Vec::new();
-    let mut scoped_inserters = Vec::new();
+    let mut consts = Vec::new();
+    let mut global = Vec::new();
+    let mut scoped = Vec::new();
     let mut wrappers = Vec::new();
 
     for item in &items {
         match item {
             Item::Const(item_const) => {
-                let inserter = generate_const_inserter(item_const);
-                const_inserters.push(inserter);
-                pub_item_mod.push(quote! {
-                    pub #item_const
-                }.into());
+                let name_str = item_const
+                    .ident
+                    .to_string()
+                    .from_case(Case::UpperSnake)
+                    .to_case(Case::Camel);
+                let const_name = &item_const.ident;
+                consts.push(quote! { (#name_str, builtins::#const_name) });
+                pub_item_mod.push(
+                    quote! {
+                        pub #item_const
+                    }
+                    .into(),
+                );
             }
             Item::Fn(item_fn) => {
-                let (inserter, wrapper) = match generate_fn_wrapper(item_fn) {
+                let (primop, wrapper) = match generate_primop_wrapper(item_fn) {
                     Ok(result) => result,
                     Err(e) => return e.to_compile_error().into(),
                 };
                 if matches!(item_fn.vis, Visibility::Public(_)) {
-                    global_inserters.push(inserter);
+                    global.push(primop);
                     pub_item_mod.push(quote! { #item_fn }.into());
                 } else {
-                    scoped_inserters.push(inserter);
-                    pub_item_mod.push(quote! {
-                        pub #item_fn
-                    }.into());
+                    scoped.push(primop);
+                    pub_item_mod.push(
+                        quote! {
+                            pub #item_fn
+                        }
+                        .into(),
+                    );
                 }
                 wrappers.push(wrapper);
             }
-            item => pub_item_mod.push(item.to_token_stream())
+            item => pub_item_mod.push(item.to_token_stream()),
         }
     }
 
+    let consts_len = consts.len();
+    let global_len = global.len();
+    let scoped_len = scoped.len();
     let output = quote! {
-        mod builtins {
+        #visibility mod #mod_name {
             #(#pub_item_mod)*
             #(#wrappers)*
+            pub const CONSTS_LEN: usize = #consts_len;
+            pub const GLOBAL_LEN: usize = #global_len;
+            pub const SCOPED_LEN: usize = #scoped_len;
         }
 
         pub struct Builtins<Ctx: BuiltinsContext> {
-            pub consts: ::std::vec::Vec<(String, ::nixjit_value::Const)>,
-            pub global: ::std::vec::Vec<(String, fn(&mut Ctx, Vec<::nixjit_eval::Value<Ctx>>) -> ::nixjit_error::Result<::nixjit_eval::Value<Ctx>>)>,
-            pub scoped: ::std::vec::Vec<(String, fn(&mut Ctx, Vec<::nixjit_eval::Value<Ctx>>) -> ::nixjit_error::Result<::nixjit_eval::Value<Ctx>>)>,
+            pub consts: [(&'static str, ::nixjit_value::Const); #mod_name::CONSTS_LEN],
+            pub global: [(&'static str, usize, fn(&mut Ctx, Vec<::nixjit_eval::Value>) -> ::nixjit_error::Result<::nixjit_eval::Value>); #mod_name::GLOBAL_LEN],
+            pub scoped: [(&'static str, usize, fn(&mut Ctx, Vec<::nixjit_eval::Value>) -> ::nixjit_error::Result<::nixjit_eval::Value>); #mod_name::SCOPED_LEN],
         }
 
         impl<Ctx: BuiltinsContext> Builtins<Ctx> {
             pub fn new() -> Self {
-                let mut consts = ::std::vec::Vec::new();
-                let mut global = ::std::vec::Vec::new();
-                let mut scoped = ::std::vec::Vec::new();
-
-                #(#const_inserters)*
-                #(#global_inserters)*
-                #(#scoped_inserters)*
-
-                Self { consts, global, scoped }
+                Self {
+                    consts: [#(#consts,)*],
+                    global: [#(#global,)*],
+                    scoped: [#(#scoped,)*],
+                }
             }
         }
     };
@@ -87,26 +101,17 @@ pub fn builtins_impl(input: TokenStream) -> TokenStream {
     output.into()
 }
 
-fn generate_const_inserter(
-    item_const: &ItemConst,
-) -> proc_macro2::TokenStream {
-    let name_str = item_const.ident.to_string().from_case(Case::UpperSnake).to_case(Case::Camel);
-    let const_name = &item_const.ident;
-
-    quote! {
-        consts.push((#name_str.to_string(), builtins::#const_name));
-    }
-}
-
-fn generate_fn_wrapper(
+fn generate_primop_wrapper(
     item_fn: &ItemFn,
 ) -> syn::Result<(proc_macro2::TokenStream, proc_macro2::TokenStream)> {
     let fn_name = &item_fn.sig.ident;
-    let name_str = fn_name.to_string().from_case(Case::Snake).to_case(Case::Camel);
+    let name_str = fn_name
+        .to_string()
+        .from_case(Case::Snake)
+        .to_case(Case::Camel);
     let wrapper_name = format_ident!("wrapper_{}", fn_name);
     let mod_name = format_ident!("builtins");
 
-    let is_pub = matches!(item_fn.vis, Visibility::Public(_));
     let mut user_args = item_fn.sig.inputs.iter().peekable();
 
     let has_ctx = if let Some(FnArg::Typed(first_arg)) = user_args.peek() {
@@ -185,15 +190,13 @@ fn generate_fn_wrapper(
         quote! { Ok(#fn_name(#call_args).into()) }
     };
 
-    let fn_type = quote! { fn(&mut Ctx, Vec<::nixjit_eval::Value<Ctx>>) -> ::nixjit_error::Result<::nixjit_eval::Value<Ctx>> };
-    let inserter = if is_pub {
-        quote! { global.push((#name_str.to_string(), #mod_name::#wrapper_name as #fn_type)); }
-    } else {
-        quote! { scoped.push((#name_str.to_string(), #mod_name::#wrapper_name as #fn_type)); }
-    };
+    let arity = arg_names.len();
+    let fn_type = quote! { fn(&mut Ctx, Vec<::nixjit_eval::Value>) -> ::nixjit_error::Result<::nixjit_eval::Value> };
+    let primop = 
+        quote! { (#name_str, #arity, #mod_name::#wrapper_name as #fn_type) };
 
     let wrapper = quote! {
-        pub fn #wrapper_name<Ctx: BuiltinsContext>(ctx: &mut Ctx, mut args: Vec<::nixjit_eval::Value<Ctx>>) -> ::nixjit_error::Result<::nixjit_eval::Value<Ctx>> {
+        pub fn #wrapper_name<Ctx: BuiltinsContext>(ctx: &mut Ctx, mut args: Vec<::nixjit_eval::Value>) -> ::nixjit_error::Result<::nixjit_eval::Value> {
             if args.len() != #arg_count {
                 return Err(::nixjit_error::Error::EvalError(format!("Function '{}' expects {} arguments, but received {}", #name_str, #arg_count, args.len())));
             }
@@ -203,5 +206,5 @@ fn generate_fn_wrapper(
         }
     };
 
-    Ok((inserter, wrapper))
+    Ok((primop, wrapper))
 }