ircd::util: Stub a TODO for util::closure.

include/ircd/util/closure.h

@@ -0,0 +1,27 @@
+// Matrix Construct
+//
+// Copyright (C) Matrix Construct Developers, Authors & Contributors
+// Copyright (C) 2016-2019 Jason Volk <jason@zemos.net>
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice is present in all copies. The
+// full license for this software is available in the LICENSE file.
+
+#pragma once
+#define HAVE_IRCD_UTIL_CLOSURE_H
+
+namespace ircd::util
+{
+	template<class function> struct closure;
+}
+
+///TODO: This is a WIP that is meant to replace the pattern of having two
+///TODO: for_each() overloads in every interface where one takes a closure
+///TODO: which returns a bool, and the other takes a void closure. In practice
+///TODO: the void overload simply calls the bool overload and returns true.
+template<class function>
+struct ircd::util::closure
+{
+
+};

include/ircd/util/util.h

@@ -59,6 +59,7 @@ namespace ircd
 #include "pretty.h"
 #include "hash.h"
 #include "fpe.h"
+#include "closure.h"
 
 // Unsorted section
 namespace ircd {