Introduce fipe library (#7281)

* Introduce fipe library

This commit introduces fipe, which permits function chaining with
UNIX pipe-like syntax.

Signed-off-by: Jonghyun Park <jh1302.park@samsung.com>
* Add License Notice

* Add a comment

diff --git a/compiler/fipe/CMakeLists.txt b/compiler/fipe/CMakeLists.txt
new file mode 100644 (file)
index 0000000..1459c60
--- /dev/null
+++ b/compiler/fipe/CMakeLists.txt
@@ -0,0 +1,11 @@
+add_library(fipe INTERFACE)
+target_include_directories(fipe INTERFACE include)
+
+if(NOT ENABLE_TEST)
+  return()
+endif(NOT ENABLE_TEST)
+
+nncc_find_package(GTest REQUIRED)
+
+GTest_AddTest(fipe_test fipe.test.cpp)
+target_link_libraries(fipe_test fipe)

diff --git a/compiler/fipe/fipe.test.cpp b/compiler/fipe/fipe.test.cpp
new file mode 100644 (file)
index 0000000..347f26f
--- /dev/null
+++ b/compiler/fipe/fipe.test.cpp
@@ -0,0 +1,73 @@
+/*
+ * Copyright (c) 2019 Samsung Electronics Co., Ltd. All Rights Reserved
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "fipe.h"
+
+#include <string>
+
+#include <gtest/gtest.h>
+
+namespace
+{
+
+int dec(int n) { return n - 1; }
+
+} // namespace
+
+TEST(FunctionPipeTests, top_level_function)
+{
+  // GCC rejects this code if dec is not wrapped by "fipe::wrap"
+  // TODO Find a better way
+  ASSERT_EQ(4 | fipe::wrap(dec), 3);
+}
+
+TEST(FunctionPipeTests, static_method)
+{
+  struct Sample
+  {
+    static int dbl(int n) { return n * 2; }
+  };
+
+  ASSERT_EQ(4 | fipe::wrap(Sample::dbl), 8);
+}
+
+TEST(FunctionPipeTests, normal_method)
+{
+  struct Sample
+  {
+  public:
+    int shift(int n) { return n + shiftamt; }
+
+  private:
+    int shiftamt = 6;
+  };
+
+  using namespace std::placeholders;
+
+  Sample s;
+
+  auto value = 4 | std::bind(&Sample::shift, &s, _1);
+
+  ASSERT_EQ(value, 10);
+}
+
+TEST(FunctionPipeTests, lambda)
+{
+  auto inc = [](int n) { return n + 1; };
+  ASSERT_EQ(4 | inc, 5);
+}
+
+TEST(FunctionPipeTests, functor) { ASSERT_EQ(4 | std::negate<int>(), -4); }

diff --git a/compiler/fipe/include/fipe.h b/compiler/fipe/include/fipe.h
new file mode 100644 (file)
index 0000000..0a661aa
--- /dev/null
+++ b/compiler/fipe/include/fipe.h
@@ -0,0 +1,40 @@
+/*
+ * Copyright (c) 2019 Samsung Electronics Co., Ltd. All Rights Reserved
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef __FIPE_H__
+#define __FIPE_H__
+
+#include <functional>
+#include <utility>
+
+namespace fipe
+{
+
+/**
+ * @brief Convert a function pointer as a callable std::function
+ *
+ * NOTE "fipe" works only for unary functions.
+ */
+template <typename Ret, typename Arg> std::function<Ret(Arg)> wrap(Ret (*p)(Arg)) { return p; }
+
+} // namespace fipe
+
+template <typename T, typename Callable> auto operator|(T &&v, Callable &&f) -> decltype(f(v))
+{
+  return std::forward<Callable>(f)(v);
+}
+
+#endif // __FIPE_H__