From f4c2e1e0448c4a4ab64e032742c3c181936e574b Mon Sep 17 00:00:00 2001
From: ADAM David Alan Martin <adam@recursive.engineer>
Date: Thu, 19 Sep 2024 00:35:59 -0400
Subject: [PATCH] Add list size primitive to type lisp.

---
 type_lisp.h | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/type_lisp.h b/type_lisp.h
index 97ac571..07c3618 100644
--- a/type_lisp.h
+++ b/type_lisp.h
@@ -48,6 +48,21 @@ namespace Alepha::Hydrogen  ::detail::  type_lisp_m
 		using type= std::tuple< Members... >;
 	};
 
+	template< TypeListType >
+	struct list_size;
+
+	template< typename ... Members >
+	struct list_size< TypeList< Members... > >
+	{
+		static const std::size_t value= sizeof...( Members );
+	};
+
+	namespace exports
+	{
+		template< TypeListType List >
+		constexpr std::size_t list_size_v= list_size< List >::value;
+	}
+
 	template< typename List >
 	struct car_impl { using type= Nil; };