merge(3p/immer): Subtree merge at 'ad3e3556d' as 'third_party/immer' r/1299

Change-Id: I9636a41ad44b4218293833fd3e9456d9b07c731b

1 files changed, 36 insertions, 0 deletions

diff --git a/third_party/immer/extra/guile/scm/detail/define.hpp b/third_party/immer/extra/guile/scm/detail/define.hpp
new file mode 100644
index 000000000000..08b6e763381f
--- /dev/null
+++ b/third_party/immer/extra/guile/scm/detail/define.hpp
@@ -0,0 +1,36 @@
+//
+// 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
+
+#ifndef SCM_AUTO_EXPORT
+#define SCM_AUTO_EXPORT 1
+#endif
+
+#include <scm/detail/subr_wrapper.hpp>
+#include <scm/list.hpp>
+
+namespace scm {
+namespace detail {
+
+template <typename Tag, typename Fn>
+static void define_impl(const std::string& name, Fn fn)
+{
+    using args_t = function_args_t<Fn>;
+    constexpr auto args_size = pack_size_v<args_t>;
+    constexpr auto has_rest  = std::is_same<pack_last_t<args_t>, scm::args>{};
+    constexpr auto arg_count = args_size - has_rest;
+    auto subr = (scm_t_subr) +subr_wrapper_aux<Tag>(fn, args_t{});
+    scm_c_define_gsubr(name.c_str(), arg_count, 0, has_rest, subr);
+#if SCM_AUTO_EXPORT
+    scm_c_export(name.c_str());
+#endif
+}
+
+} // namespace detail
+} // namespace scm