diff --git a/packages/rose/src/ad.rose b/packages/rose/src/ad.rose
index 5496ea4..0e892f3 100644
--- a/packages/rose/src/ad.rose
+++ b/packages/rose/src/ad.rose
@@ -27,19 +27,19 @@ instance AD u64 {
 }
 
 instance AD f32 {
-  type D = (f32, f32)
+  type D = f32, f32
 }
 
 instance AD f64 {
-  type D = (f64, f64)
+  type D = f64, f64
 }
 
 instance T (AD T) => AD []T {
-  type D = []((AD T).D)
+  type D = [](AD T).D
 }
 
 instance A B (AD A) (AD B) => AD (A, B) {
-  type D = ((AD A).D, (AD B).D)
+  type D = (AD A).D, (AD B).D
 }
 
 instance A B (AD A) (AD B) => AD (A | B) {
diff --git a/packages/rose/src/array.rose b/packages/rose/src/array.rose
index 0dda797..02204af 100644
--- a/packages/rose/src/array.rose
+++ b/packages/rose/src/array.rose
@@ -19,12 +19,12 @@ def linearize do_for = do_for
 
 pub def T => new (n : u32) (f : u32 -> T) : []T =
   let xs = init n
-  let _ = do_for (n, \i => set xs i (f i))
+  let _ = do_for (n, i => set xs i (f i))
   in xs
 
-def transpose do_for ((n, f) : (u32, u32 -> ())) : ((), () -> ()) =
+def transpose do_for ((n, f) : (u32, u32 -> ())) : (), () -> () =
   let g : u32 -> ((), () -> ()) = transpose f
-  let hs : [](() -> ()) = new n (\i => let (_, h) = g i in h)
-  in ((), \() => do_for (n, \i => hs i ()))
+  let hs : [](() -> ()) = new n i => let _, h = g i in h
+  in (), () => do_for (n, i => hs i ())
 
-pub def A B => map (f : A -> B) (xs : []A) : []B = new (len xs) (\i => f (xs i))
+pub def A B => map (f : A -> B) (xs : []A) : []B = new (len xs) i => f (xs i)
diff --git a/packages/rose/src/parse.ts b/packages/rose/src/parse.ts
index deb5eed..9961abb 100644
--- a/packages/rose/src/parse.ts
+++ b/packages/rose/src/parse.ts
@@ -81,19 +81,21 @@ export interface Class {
 }
 
 export enum TypeKind {
+  Unit,
   Name,
   Class,
   Array,
-  Tuple,
+  Pair,
   Sum,
   Function,
 }
 
 export type Type =
+  | { kind: TypeKind.Unit }
   | { kind: TypeKind.Name; name: TokenId }
   | { kind: TypeKind.Class; class: Class; name: TokenId }
   | { kind: TypeKind.Array; elem: Type }
-  | { kind: TypeKind.Tuple; member: Type[] }
+  | { kind: TypeKind.Pair; left: Type; right: Type }
   | { kind: TypeKind.Sum; left: Type; right: Type }
   | { kind: TypeKind.Function; dom: Type; cod: Type };
 
@@ -103,19 +105,23 @@ export interface Param {
 }
 
 export enum BindKind {
+  Unit,
   Name,
-  Tuple,
+  Pair,
 }
 
 export type Bind =
+  | { kind: BindKind.Unit }
   | { kind: BindKind.Name; name: TokenId }
-  | { kind: BindKind.Tuple; member: Bind[] };
+  | { kind: BindKind.Pair; left: Bind; right: Bind };
 
 export enum ExprKind {
   Name,
+  Unit,
+  Str,
   Num,
   Array,
-  Tuple,
+  Pair,
   Inl,
   Inr,
   Lambda,
@@ -130,9 +136,11 @@ export enum ExprKind {
 
 export type Expr =
   | { kind: ExprKind.Name; name: TokenId }
+  | { kind: ExprKind.Unit }
+  | { kind: ExprKind.Str; str: TokenId }
   | { kind: ExprKind.Num; num: TokenId }
   | { kind: ExprKind.Array; elem: Expr[] }
-  | { kind: ExprKind.Tuple; member: Expr[] }
+  | { kind: ExprKind.Pair; left: Expr; right: Expr }
   | { kind: ExprKind.Inl; val: Expr }
   | { kind: ExprKind.Inr; val: Expr }
   | { kind: ExprKind.Lambda; param: Param; body: Expr }
diff --git a/packages/rose/src/prelude.rose b/packages/rose/src/prelude.rose
index d5238d8..4a31ad4 100644
--- a/packages/rose/src/prelude.rose
+++ b/packages/rose/src/prelude.rose
@@ -1,2 +1,6 @@
 pub use { len, map, new } from "./array.js"
 pub use { +, -, *, / } from "./num.js"
+
+pub def true = bool.true
+
+pub def false = bool.false