lude

commit dff6da1a5d97c948f8ea1ed43a9b92232ab2fde4
parent e9e58113e990affacef44e78376bcd6977fbc7a7
Author: Robert Russell <robert@rr3.xyz>
Date:   Tue, 10 Mar 2026 18:48:52 -0700

Add Pair and Either

Diffstat:
A
src/Lude/Either.hs
 | 
13
+++++++++++++
A
src/Lude/Pair.hs
 | 
21
+++++++++++++++++++++

2 files changed, 34 insertions(+), 0 deletions(-)
diff --git a/src/Lude/Either.hs b/src/Lude/Either.hs
@@ -0,0 +1,13 @@
+module Lude.Either (
+    Either (..),
+    type (+),
+) where
+
+-- TODO: It's probably not worth defining our own type here.
+
+--------------------------------------------------------------------------------
+
+data Either a b = L a | R b
+
+type (+) = Either
+infixl 6 +
diff --git a/src/Lude/Pair.hs b/src/Lude/Pair.hs
@@ -0,0 +1,21 @@
+module Lude.Pair (
+    Pair,
+    type (×),
+    Fst,
+    Snd,
+) where
+
+--------------------------------------------------------------------------------
+
+type Pair = (,)
+
+type (×) = Pair
+infixl 7 ×
+
+--------------------------------------------------------------------------------
+
+type family Fst (x :: i × j) :: i where
+    Fst '(a, b) = a
+
+type family Snd (x :: i × j) :: j where
+    Snd '(a, b) = b