Merge pull request #793 from elbeno/clean-up-flow

🎨 Refactor flow builder

Author: elbeno

CMakeLists.txt

@@ -241,15 +241,17 @@ target_sources(
               include
               FILES
               include/flow/builder.hpp
-              include/flow/common.hpp
-              include/flow/detail/par.hpp
-              include/flow/detail/seq.hpp
-              include/flow/detail/walk.hpp
+              include/flow/dsl/par.hpp
+              include/flow/dsl/seq.hpp
+              include/flow/dsl/subgraph_identity.hpp
+              include/flow/dsl/walk.hpp
               include/flow/flow.hpp
+              include/flow/func_list.hpp
               include/flow/graph_builder.hpp
               include/flow/graphviz_builder.hpp
-              include/flow/impl.hpp
+              include/flow/log.hpp
               include/flow/run.hpp
+              include/flow/service.hpp
               include/flow/step.hpp)
 
 add_library(cib_seq INTERFACE)

include/flow/builder.hpp

@@ -1,30 +1,47 @@
 #pragma once
 
-#include <flow/common.hpp>
+#include <flow/dsl/walk.hpp>
 #include <flow/graph_builder.hpp>
-#include <flow/impl.hpp>
 #include <flow/log.hpp>
 
-#include <stdx/compiler.hpp>
 #include <stdx/ct_string.hpp>
-#include <stdx/panic.hpp>
+#include <stdx/tuple.hpp>
+#include <stdx/tuple_algorithms.hpp>
+#include <stdx/type_traits.hpp>
+
+#include <utility>
 
 namespace flow {
-template <stdx::ct_string Name = "",
-          typename LogPolicy = flow::log_policy_t<Name>>
-using builder = graph<Name, LogPolicy>;
+template <typename Renderer, flow::dsl::subgraph... Fragments>
+class builder_for {
+    template <typename Tag>
+    friend constexpr auto tag_invoke(Tag, builder_for const &b) {
+        return b.fragments.apply([](auto const &...frags) {
+            return stdx::tuple_cat(Tag{}(frags)...);
+        });
+    }
 
-template <stdx::ct_string Name = "", typename LogPolicy = log_policy_t<Name>>
-struct service {
-    using builder_t = builder<Name, LogPolicy>;
-    using interface_t = FunctionPtr;
-
-    CONSTEVAL static auto uninitialized() -> interface_t {
-        return [] {
-            using namespace stdx::literals;
-            stdx::panic<"Attempting to run flow ("_cts + Name +
-                        ") before it is initialized"_cts>();
-        };
+  public:
+    using interface_t = typename Renderer::interface_t;
+    constexpr static auto name = Renderer::name;
+
+    template <flow::dsl::subgraph... Ns>
+    [[nodiscard]] constexpr auto add(Ns &&...ns) {
+        return fragments.apply([&](auto &...frags) {
+            return builder_for<Renderer, Fragments...,
+                               stdx::remove_cvref_t<Ns>...>{
+                {frags..., std::forward<Ns>(ns)...}};
+        });
     }
+
+    template <typename BuilderValue>
+    [[nodiscard]] constexpr static auto build() {
+        return Renderer::template render<BuilderValue>();
+    }
+
+    stdx::tuple<Fragments...> fragments;
 };
+
+template <stdx::ct_string Name = "", typename LogPolicy = log_policy_t<Name>>
+using builder = builder_for<graph_builder<Name, LogPolicy>>;
 } // namespace flow

include/flow/common.hpp

@@ -1,7 +1,7 @@
 #pragma once
 
-#include <flow/detail/walk.hpp>
-#include <flow/subgraph_identity.hpp>
+#include <flow/dsl/subgraph_identity.hpp>
+#include <flow/dsl/walk.hpp>
 
 #include <stdx/tuple_algorithms.hpp>
 
@@ -59,7 +59,7 @@ template <flow::dsl::subgraph Lhs, flow::dsl::subgraph Rhs>
 }
 
 template <typename Cond, flow::dsl::subgraph Lhs, flow::dsl::subgraph Rhs,
-          flow::subgraph_identity Identity>
+          flow::dsl::subgraph_identity Identity>
 constexpr auto make_runtime_conditional(Cond,
                                         flow::dsl::par<Lhs, Rhs, Identity>) {
     auto lhs = make_runtime_conditional(Cond{}, Lhs{});

include/flow/detail/par.hpp renamed to include/flow/dsl/par.hpp

@@ -1,8 +1,8 @@
 #pragma once
 
 #include <cib/detail/runtime_conditional.hpp>
-#include <flow/detail/walk.hpp>
-#include <flow/subgraph_identity.hpp>
+#include <flow/dsl/subgraph_identity.hpp>
+#include <flow/dsl/walk.hpp>
 
 #include <stdx/tuple_algorithms.hpp>
 
@@ -72,7 +72,7 @@ template <flow::dsl::subgraph Lhs, flow::dsl::subgraph Rhs>
 }
 
 template <typename Cond, flow::dsl::subgraph Lhs, flow::dsl::subgraph Rhs,
-          flow::subgraph_identity Identity, typename EdgeCond>
+          flow::dsl::subgraph_identity Identity, typename EdgeCond>
 constexpr auto
 make_runtime_conditional(Cond, flow::dsl::seq<Lhs, Rhs, Identity, EdgeCond>) {
     auto lhs = make_runtime_conditional(Cond{}, Lhs{});

include/flow/detail/seq.hpp renamed to include/flow/dsl/seq.hpp

@@ -0,0 +1,5 @@
+#pragma once
+
+namespace flow::dsl {
+enum struct subgraph_identity : bool { VALUE, REFERENCE };
+}

include/flow/dsl/subgraph_identity.hpp

@@ -1,6 +1,6 @@
 #pragma once
 
-#include <flow/subgraph_identity.hpp>
+#include <flow/dsl/subgraph_identity.hpp>
 
 #include <stdx/concepts.hpp>
 #include <stdx/tuple.hpp>

include/flow/detail/walk.hpp renamed to include/flow/dsl/walk.hpp

@@ -1,9 +1,7 @@
 #pragma once
 
-#include <flow/builder.hpp>
-#include <flow/common.hpp>
-#include <flow/detail/par.hpp>
-#include <flow/detail/seq.hpp>
-#include <flow/impl.hpp>
+#include <flow/dsl/par.hpp>
+#include <flow/dsl/seq.hpp>
 #include <flow/run.hpp>
+#include <flow/service.hpp>
 #include <flow/step.hpp>

include/flow/flow.hpp

@@ -1,6 +1,5 @@
 #pragma once
 
-#include <flow/common.hpp>
 #include <flow/log.hpp>
 #include <log/log.hpp>
 
@@ -11,18 +10,10 @@
 
 #include <algorithm>
 #include <array>
-#include <concepts>
 #include <cstddef>
 #include <iterator>
 
 namespace flow {
-template <typename T>
-concept log_policy = requires {
-    {
-        T::template log<default_log_env>(stdx::ct_format<"">())
-    } -> std::same_as<void>;
-};
-
 namespace detail {
 template <stdx::ct_string FlowName, log_policy LogPolicy, typename CTNode>
 constexpr static auto run_func = []() -> void {
@@ -35,28 +26,7 @@ constexpr static auto run_func = []() -> void {
         typename CTNode::func_t{}();
     }
 };
-} // namespace detail
-
-template <stdx::ct_string Name, log_policy LogPolicy, std::size_t NumSteps>
-struct impl {
-    using node_t = FunctionPtr;
-    std::array<FunctionPtr, NumSteps> functionPtrs{};
-
-    constexpr static auto name = Name;
-
-    template <typename CTNode>
-    constexpr static auto create_node(CTNode) -> node_t {
-        constexpr auto fp = detail::run_func<Name, LogPolicy, CTNode>;
-        return fp;
-    }
-
-    constexpr explicit(true) impl(stdx::span<node_t const, NumSteps> steps) {
-        std::copy(std::cbegin(steps), std::cend(steps),
-                  std::begin(functionPtrs));
-    }
-};
 
-namespace detail {
 template <stdx::ct_string Name, log_policy LogPolicy, auto... FuncPtrs>
 struct inlined_func_list {
     constexpr static auto active = sizeof...(FuncPtrs) > 0;
@@ -75,4 +45,24 @@ struct inlined_func_list {
     }
 };
 } // namespace detail
+
+template <stdx::ct_string Name, log_policy LogPolicy, std::size_t NumSteps>
+struct func_list {
+    using node_t = auto (*)() -> void;
+    std::array<node_t, NumSteps> nodes{};
+
+    template <typename CTNode>
+    constexpr static auto create_node(CTNode) -> node_t {
+        constexpr auto fp = detail::run_func<Name, LogPolicy, CTNode>;
+        return fp;
+    }
+
+    constexpr explicit(true)
+        func_list(stdx::span<node_t const, NumSteps> steps) {
+        std::copy(std::cbegin(steps), std::cend(steps), std::begin(nodes));
+    }
+
+    template <node_t... Fs>
+    using finalized_t = detail::inlined_func_list<Name, LogPolicy, Fs...>;
+};
 } // namespace flow

include/flow/impl.hpp renamed to include/flow/func_list.hpp

@@ -1,8 +1,7 @@
 #pragma once
 
-#include <flow/common.hpp>
-#include <flow/detail/walk.hpp>
-#include <flow/impl.hpp>
+#include <flow/dsl/walk.hpp>
+#include <flow/func_list.hpp>
 
 #include <stdx/ct_string.hpp>
 #include <stdx/cx_multimap.hpp>
@@ -58,9 +57,9 @@ template <typename T> using name_for = typename T::name_t;
     });
 }
 
-template <stdx::ct_string Name,
-          template <stdx::ct_string, typename, std::size_t> typename Impl,
-          typename LogPolicy = log_policy_t<Name>>
+template <stdx::ct_string Name, typename LogPolicy = log_policy_t<Name>,
+          template <stdx::ct_string, typename, std::size_t> typename Impl =
+              func_list>
 struct graph_builder {
     // NOLINTBEGIN(readability-function-cognitive-complexity)
     template <typename Output, std::size_t N, std::size_t E>
@@ -234,29 +233,29 @@ struct graph_builder {
         return topo_sort<output_t>(g);
     }
 
+    constexpr static auto name = Name;
+    using interface_t = auto (*)() -> void;
+
     template <typename Initialized> class built_flow {
         constexpr static auto built() {
             constexpr auto v = Initialized::value;
             constexpr auto built = build(v);
             static_assert(built.has_value(),
                           "Topological sort failed: cycle in flow");
 
-            constexpr auto functionPtrs = built->functionPtrs;
-            constexpr auto size = std::size(functionPtrs);
-            constexpr auto name = built->name;
-
+            using impl_t = typename decltype(built)::value_type;
+            constexpr auto nodes = built->nodes;
             return [&]<std::size_t... Is>(std::index_sequence<Is...>) {
-                return detail::inlined_func_list<name, LogPolicy,
-                                                 functionPtrs[Is]...>{};
-            }(std::make_index_sequence<size>{});
+                return typename impl_t::template finalized_t<nodes[Is]...>{};
+            }(std::make_index_sequence<std::size(nodes)>{});
         }
 
         constexpr static auto run() { built()(); }
 
       public:
         // NOLINTNEXTLINE(google-explicit-constructor)
-        constexpr explicit(false) operator FunctionPtr() const { return run; }
-        constexpr auto operator()() const -> void { run(); }
+        constexpr explicit(false) operator interface_t() const { return run; }
+        constexpr auto operator()() const { return run(); }
         constexpr static bool active = decltype(built())::active;
     };
 
@@ -265,34 +264,4 @@ struct graph_builder {
         return {};
     }
 };
-
-template <stdx::ct_string Name = "", typename LogPolicy = log_policy_t<Name>,
-          typename Renderer = graph_builder<Name, impl, LogPolicy>,
-          flow::dsl::subgraph... Fragments>
-class graph {
-    template <typename Tag>
-    friend constexpr auto tag_invoke(Tag, graph const &g) {
-        return g.fragments.apply([](auto const &...frags) {
-            return stdx::tuple_cat(Tag{}(frags)...);
-        });
-    }
-
-  public:
-    template <flow::dsl::subgraph... Ns>
-    [[nodiscard]] constexpr auto add(Ns &&...ns) {
-        return fragments.apply([&](auto &...frags) {
-            return graph<Name, LogPolicy, Renderer, Fragments...,
-                         stdx::remove_cvref_t<Ns>...>{
-                {frags..., std::forward<Ns>(ns)...}};
-        });
-    }
-
-    template <typename BuilderValue>
-    [[nodiscard]] constexpr static auto build() {
-        return Renderer::template render<BuilderValue>();
-    }
-
-    constexpr static auto name = Name;
-    stdx::tuple<Fragments...> fragments;
-};
 } // namespace flow