From 4d37acdda7900c121bed1915898800abc346a4a7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Lu=C3=ADs=20Murta?= <luis@murta.dev>
Date: Wed, 6 Aug 2025 21:07:05 +0100
Subject: [PATCH] feat: simple pipeline

---
 CMakeLists.txt                | 10 ++++-
 include/freepipe/freepipe.hpp | 72 +++++++++++++++++++++++++++++++++++
 tests/CMakeLists.txt          |  5 +++
 tests/pipe.test.cpp           | 25 ++++++++++++
 4 files changed, 110 insertions(+), 2 deletions(-)
 create mode 100644 include/freepipe/freepipe.hpp
 create mode 100644 tests/pipe.test.cpp

diff --git a/CMakeLists.txt b/CMakeLists.txt
index a147ad7..fae5e92 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,6 +1,6 @@
-cmake_minimum_required(VERSION 3.20)
+cmake_minimum_required(VERSION 3.20...4.0)
 project(
-  pipeline_asio
+  pipe
   VERSION 0.1.0
   LANGUAGES CXX)
 
@@ -9,5 +9,11 @@ find_package(fmt REQUIRED)
 add_subdirectory(external/pipeline)
 add_subdirectory(external/pipes)
 
+# Specify the include directories include_directories(include)
+
+add_library(pipe INTERFACE)
+target_compile_features(pipe INTERFACE cxx_std_23)
+target_include_directories(pipe INTERFACE include)
+
 enable_testing()
 add_subdirectory(tests)
diff --git a/include/freepipe/freepipe.hpp b/include/freepipe/freepipe.hpp
new file mode 100644
index 0000000..2e99cc5
--- /dev/null
+++ b/include/freepipe/freepipe.hpp
@@ -0,0 +1,72 @@
+// Copyright 2025, Luís Murta
+// SPDX-License-Identifier: MIT
+
+#pragma once
+
+#include <any>
+#include <concepts>
+#include <functional>
+#include <optional>
+#include <ostream>
+#include <tuple>
+#include <utility>
+
+namespace freepipe {
+
+template <typename... Args> struct Task {
+  explicit constexpr Task(Args &&...args)
+    requires(sizeof...(Args) > 0)
+      : args_(std::forward<Args>(args)...) {}
+
+  explicit constexpr Task()
+    requires(sizeof...(Args) == 0)
+  {}
+
+  constexpr auto const &operator*() const & { return args_; }
+  constexpr auto &operator*() & { return args_; }
+  constexpr auto &&operator*() && { return std::move(args_); }
+  constexpr auto const &&operator*() const && { return std::move(args_); }
+
+private:
+  std::tuple<Args...> args_;
+};
+
+template <typename... Args, std::regular_invocable<Args...> F>
+constexpr auto operator|(Task<Args...> const &task, F &&func) {
+  using R = std::invoke_result_t<F, Args...>;
+
+  if constexpr (std::is_void_v<R>) {
+    std::apply(std::forward<F>(func), *task);
+    return Task<>{};
+  } else {
+    return Task<R>{std::apply(std::forward<F>(func), *task)};
+  }
+}
+
+template <typename... Args, std::regular_invocable<Args...> F>
+constexpr auto operator|(Task<Args...> &&task, F &&func) {
+  using R = std::invoke_result_t<F, Args...>;
+
+  if constexpr (std::is_void_v<R>) {
+    std::apply(std::forward<F>(func), *std::move(task));
+    return Task<>{};
+  } else {
+    return Task<R>{std::apply(std::forward<F>(func), *std::move(task))};
+  }
+}
+
+template <typename... Args, typename CharT, typename Traits = std::char_traits<CharT>>
+constexpr auto operator|(Task<Args...> const &task, std::basic_ostream<CharT, Traits> &os) {
+  std::apply([&os](auto &&...args) { ((os << args << '\n'), ...); }, *task);
+  return Task<>{};
+}
+
+template <typename... Args, typename CharT, typename Traits = std::char_traits<CharT>>
+constexpr auto operator|(Task<Args...> &&task, std::basic_ostream<CharT, Traits> &os) {
+  std::apply([&os](auto &&...args) { ((os << args << '\n'), ...); }, *std::move(task));
+  return Task<>{};
+}
+
+class Pipe : public Task<> {};
+
+} // namespace freepipe
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 62377b6..63e340c 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -5,3 +5,8 @@ target_compile_features(pipeline.test PUBLIC cxx_std_23)
 target_link_libraries(pipeline.test benchmark::benchmark_main
                       pipeline::pipeline joboccara::pipes)
 add_test(NAME pipeline.test COMMAND pipeline.test)
+
+find_package(GTest REQUIRED)
+add_executable(pipe.test pipe.test.cpp)
+target_compile_features(pipe.test PUBLIC cxx_std_23)
+target_link_libraries(pipe.test GTest::gtest_main pipe)
diff --git a/tests/pipe.test.cpp b/tests/pipe.test.cpp
new file mode 100644
index 0000000..2a9ddac
--- /dev/null
+++ b/tests/pipe.test.cpp
@@ -0,0 +1,25 @@
+#include <freepipe/freepipe.hpp>
+#include <gtest/gtest.h>
+#include <iostream>
+
+namespace freepipe {
+
+TEST(PipeTest, Single) {
+  Pipe p;
+
+  auto r = p | [] { return 42; } |
+           [](auto result) {
+             EXPECT_EQ(result, 42);
+             return result;
+           } |
+           std::cout |
+           [] {
+             SUCCEED();
+             return 0;
+           } |
+           [](auto result) { EXPECT_EQ(result, 0); } | [] { return 0; };
+
+  EXPECT_EQ(*r, std::tuple{0});
+}
+
+} // namespace freepipe