From f8398804d351667a7b887b89f6f70c7d5c407d22 Mon Sep 17 00:00:00 2001
From: Marvin Borner
Date: Mon, 25 Mar 2024 16:21:54 +0100
Subject: More samples and definitions

---
 std/Number/Unary.bruijn | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

(limited to 'std/Number/Unary.bruijn')

diff --git a/std/Number/Unary.bruijn b/std/Number/Unary.bruijn
index 5041614..3b58ceb 100644
--- a/std/Number/Unary.bruijn
+++ b/std/Number/Unary.bruijn
@@ -173,6 +173,26 @@ mod* [[1 &[[(0 ⋀? (2 ≤? 1)) case-rec case-end]] (1 : true) k]] ⧗ Unary →
 	case-rec (1 - 3) : true
 	case-end 1 : false
 
+# returns true if the number is even (remainder mod 2 == 0)
+even? [=?(0 % (+2u))] ⧗ Unary → Boolean
+
+=²?‣ even?
+
+:test (=²?(+0u)) (true)
+:test (=²?(+1u)) (false)
+:test (=²?(+41u)) (false)
+:test (=²?(+42u)) (true)
+
+# returns true if the number is odd (remainder mod 2 == 1)
+odd? ¬‣ ∘ even? ⧗ Unary → Boolean
+
+≠²?‣ odd?
+
+:test (≠²?(+0u)) (false)
+:test (≠²?(+1u)) (true)
+:test (≠²?(+41u)) (true)
+:test (≠²?(+42u)) (false)
+
 # exponentiates two unary number
 # doesn't give correct results for x^0
 pow* [[1 0]] ⧗ Unary → Unary → Unary
-- 
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