From 58bb86fd2f0ecd740fc5bc8078de44221c12c70a Mon Sep 17 00:00:00 2001
From: Steven Le Rouzic <steven.lerouzic@gmail.com>
Date: Fri, 22 Nov 2024 17:13:03 +0100
Subject: Add a niche to box

---
 asl/meta.hpp | 9 +++++++++
 1 file changed, 9 insertions(+)

(limited to 'asl/meta.hpp')

diff --git a/asl/meta.hpp b/asl/meta.hpp
index f0397a1..72b36fd 100644
--- a/asl/meta.hpp
+++ b/asl/meta.hpp
@@ -160,4 +160,13 @@ template<typename T, int N> struct _is_array_helper<T[N]> : true_type  {};
 
 template<typename T> concept is_array = _is_array_helper<T>::value;
 
+struct niche {};
+
+template<typename T>
+concept has_niche = constructible_from<T, niche> &&
+    requires (const T& value, niche n)
+    {
+        { value == n } -> same_as<bool>;
+    };
+
 } // namespace asl
-- 
cgit