1 files changed, 99 insertions, 0 deletions
diff --git a/src/boost/libs/yap/test/compile_is_expr.cpp b/src/boost/libs/yap/test/compile_is_expr.cpp
new file mode 100644
index 00000000..3bf030d4
--- /dev/null
+++ b/src/boost/libs/yap/test/compile_is_expr.cpp
@@ -0,0 +1,99 @@
+// Copyright (C) 2016-2018 T. Zachary Laine
+//
+// Distributed under the Boost Software License, Version 1.0. (See
+// accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+#include <boost/yap/expression.hpp>
+
+
+namespace yap = boost::yap;
+
+struct alternate_expr_1
+{
+    static const yap::expr_kind kind = yap::expr_kind::plus;
+    boost::hana::tuple<> elements;
+};
+
+struct alternate_expr_2
+{
+    static const yap::expr_kind kind = yap::expr_kind::plus;
+    boost::hana::tuple<int, double> elements;
+};
+
+
+struct non_expr_1
+{};
+
+struct non_expr_2
+{
+    boost::hana::tuple<int, double> elements;
+};
+
+struct non_expr_3
+{
+    static const int kind = 0;
+    boost::hana::tuple<int, double> elements;
+};
+
+struct non_expr_4
+{
+    int kind;
+    boost::hana::tuple<int, double> elements;
+};
+
+struct non_expr_5
+{
+    static const yap::expr_kind kind = yap::expr_kind::plus;
+};
+
+struct non_expr_6
+{
+    static const yap::expr_kind kind = yap::expr_kind::plus;
+    int elements;
+};
+
+
+void compile_is_expr()
+{
+    static_assert(
+        yap::is_expr<yap::terminal<yap::expression, double>>::value, "");
+
+    static_assert(
+        yap::is_expr<yap::terminal<yap::expression, double> const>::value, "");
+    static_assert(
+        yap::is_expr<yap::terminal<yap::expression, double> const &>::value,
+        "");
+    static_assert(
+        yap::is_expr<yap::terminal<yap::expression, double> &>::value, "");
+    static_assert(
+        yap::is_expr<yap::terminal<yap::expression, double> &&>::value, "");
+
+    {
+        using namespace yap::literals;
+        static_assert(yap::is_expr<decltype(1_p)>::value, "");
+    }
+
+    static_assert(
+        yap::is_expr<yap::expression<
+            yap::expr_kind::unary_plus,
+            boost::hana::tuple<yap::terminal<yap::expression, double>>>>::value,
+        "");
+    static_assert(
+        yap::is_expr<yap::expression<
+            yap::expr_kind::plus,
+            boost::hana::tuple<
+                yap::terminal<yap::expression, double>,
+                yap::terminal<yap::expression, double>>>>::value,
+        "");
+
+    static_assert(yap::is_expr<alternate_expr_1>::value, "");
+    static_assert(yap::is_expr<alternate_expr_2>::value, "");
+
+    static_assert(!yap::is_expr<int>::value, "");
+    static_assert(!yap::is_expr<non_expr_1>::value, "");
+    static_assert(!yap::is_expr<non_expr_2>::value, "");
+    static_assert(!yap::is_expr<non_expr_3>::value, "");
+    static_assert(!yap::is_expr<non_expr_4>::value, "");
+    static_assert(!yap::is_expr<non_expr_5>::value, "");
+    static_assert(!yap::is_expr<non_expr_6>::value, "");
+}