1 files changed, 62 insertions, 0 deletions
diff --git a/extra/guile/scm/detail/finalizer_wrapper.hpp b/extra/guile/scm/detail/finalizer_wrapper.hpp
new file mode 100644
index 000000000000..258249eb2c73
--- /dev/null
+++ b/extra/guile/scm/detail/finalizer_wrapper.hpp
@@ -0,0 +1,62 @@
+//
+// immer: immutable data structures for C++
+// Copyright (C) 2016, 2017, 2018 Juan Pedro Bolivar Puente
+//
+// This software is distributed under the Boost Software License, Version 1.0.
+// See accompanying file LICENSE or copy at http://boost.org/LICENSE_1_0.txt
+//
+
+#pragma once
+
+#include <scm/detail/invoke.hpp>
+#include <scm/detail/function_args.hpp>
+#include <scm/detail/convert.hpp>
+
+namespace scm {
+namespace detail {
+// this anonymous namespace should help avoiding registration clashes
+// among translation units.
+namespace {
+
+template <typename Tag, typename Fn>
+auto finalizer_wrapper_impl(Fn fn, pack<>)
+{
+    check_call_once<Tag, Fn>();
+    static const Fn fn_ = fn;
+    return [] { invoke(fn_); };
+}
+template <typename Tag, typename Fn, typename T1>
+auto finalizer_wrapper_impl(Fn fn, pack<T1>)
+{
+    check_call_once<Tag, Fn>();
+    static const Fn fn_ = fn;
+    return [] (SCM a1) { invoke(fn_, to_cpp<T1>(a1)); };
+}
+template <typename Tag, typename Fn, typename T1, typename T2>
+auto finalizer_wrapper_impl(Fn fn, pack<T1, T2>)
+{
+    check_call_once<Tag, Fn>();
+    static const Fn fn_ = fn;
+    return [] (SCM a1, SCM a2) {
+        invoke(fn_, to_cpp<T1>(a1), to_cpp<T2>(a2));
+    };
+}
+template <typename Tag, typename Fn, typename T1, typename T2, typename T3>
+auto finalizer_wrapper_impl(Fn fn, pack<T1, T2, T3>)
+{
+    check_call_once<Tag, Fn>();
+    static const Fn fn_ = fn;
+    return [] (SCM a1, SCM a2, SCM a3) {
+        invoke(fn_, to_cpp<T1>(a1), to_cpp<T2>(a2), to_cpp<T3>(a3));
+    };
+}
+
+template <typename Tag, typename Fn>
+auto finalizer_wrapper(Fn fn)
+{
+    return finalizer_wrapper_impl<Tag>(fn, function_args_t<Fn>{});
+}
+
+} // anonymous namespace
+} // namespace detail
+} // namespace scm