Add a macro which generates a SFINAE template for checking NUClear wo…

…rds (#155)

All of the NUClear DSL words follow a similar pattern for working out if
a DSL word exists.
This makes a macro which can generate this pattern rather than having
almost identical lines all through individual files.

src/dsl/fusion/BindFusion.hpp

@@ -27,12 +27,15 @@
 #include "../../util/FunctionFusion.hpp"
 #include "../operation/DSLProxy.hpp"
 #include "FindWords.hpp"
-#include "has_bind.hpp"
+#include "has_nuclear_dsl_method.hpp"
 
 namespace NUClear {
 namespace dsl {
     namespace fusion {
 
+        /// Make a SFINAE type to check if a word has a run_inline method
+        HAS_NUCLEAR_DSL_METHOD(bind);
+
         /**
          * This is our Function Fusion wrapper class that allows it to call bind functions.
          *

src/dsl/fusion/GetFusion.hpp

@@ -27,12 +27,15 @@
 #include "../../util/tuplify.hpp"
 #include "../operation/DSLProxy.hpp"
 #include "FindWords.hpp"
-#include "has_get.hpp"
+#include "has_nuclear_dsl_method.hpp"
 
 namespace NUClear {
 namespace dsl {
     namespace fusion {
 
+        /// Make a SFINAE type to check if a word has a get method
+        HAS_NUCLEAR_DSL_METHOD(get);
+
         /**
          * This is our Function Fusion wrapper class that allows it to call get functions.
          *

src/dsl/fusion/GroupFusion.hpp

@@ -30,12 +30,15 @@
 #include "../../threading/Reaction.hpp"
 #include "../operation/DSLProxy.hpp"
 #include "FindWords.hpp"
-#include "has_group.hpp"
+#include "has_nuclear_dsl_method.hpp"
 
 namespace NUClear {
 namespace dsl {
     namespace fusion {
 
+        /// Make a SFINAE type to check if a word has a group method
+        HAS_NUCLEAR_DSL_METHOD(group);
+
         // Default case where there are no group words
         template <typename Words>
         struct GroupFuser {};

src/dsl/fusion/InlineFusion.hpp

@@ -27,12 +27,15 @@
 #include "../../util/Inline.hpp"
 #include "../operation/DSLProxy.hpp"
 #include "FindWords.hpp"
-#include "has_run_inline.hpp"
+#include "has_nuclear_dsl_method.hpp"
 
 namespace NUClear {
 namespace dsl {
     namespace fusion {
 
+        /// Make a SFINAE type to check if a word has a run_inline method
+        HAS_NUCLEAR_DSL_METHOD(run_inline);
+
         // Default case where there are no Inline words
         template <typename Words>
         struct InlineFuser {};

src/dsl/fusion/PoolFusion.hpp

@@ -29,12 +29,15 @@
 #include "../../threading/ReactionTask.hpp"
 #include "../operation/DSLProxy.hpp"
 #include "FindWords.hpp"
-#include "has_pool.hpp"
+#include "has_nuclear_dsl_method.hpp"
 
 namespace NUClear {
 namespace dsl {
     namespace fusion {
 
+        /// Make a SFINAE type to check if a word has a pool method
+        HAS_NUCLEAR_DSL_METHOD(pool);
+
         // Default case where there are no pool words
         template <typename Words>
         struct PoolFuser {};

src/dsl/fusion/PostconditionFusion.hpp

@@ -26,12 +26,15 @@
 #include "../../threading/ReactionTask.hpp"
 #include "../operation/DSLProxy.hpp"
 #include "FindWords.hpp"
-#include "has_postcondition.hpp"
+#include "has_nuclear_dsl_method.hpp"
 
 namespace NUClear {
 namespace dsl {
     namespace fusion {
 
+        /// Make a SFINAE type to check if a word has a postcondition method
+        HAS_NUCLEAR_DSL_METHOD(postcondition);
+
         // Default case where there are no postcondition words
         template <typename Words>
         struct PostconditionFuser {};

src/dsl/fusion/PreconditionFusion.hpp

@@ -26,12 +26,15 @@
 #include "../../threading/ReactionTask.hpp"
 #include "../operation/DSLProxy.hpp"
 #include "FindWords.hpp"
-#include "has_precondition.hpp"
+#include "has_nuclear_dsl_method.hpp"
 
 namespace NUClear {
 namespace dsl {
     namespace fusion {
 
+        /// Make a SFINAE type to check if a word has a precondition method
+        HAS_NUCLEAR_DSL_METHOD(precondition);
+
         // Default case where there are no precondition words
         template <typename Words>
         struct PreconditionFuser {};

src/dsl/fusion/PriorityFusion.hpp

@@ -26,12 +26,15 @@
 #include "../../threading/ReactionTask.hpp"
 #include "../operation/DSLProxy.hpp"
 #include "FindWords.hpp"
-#include "has_priority.hpp"
+#include "has_nuclear_dsl_method.hpp"
 
 namespace NUClear {
 namespace dsl {
     namespace fusion {
 
+        /// Make a SFINAE type to check if a word has a priority method
+        HAS_NUCLEAR_DSL_METHOD(priority);
+
         // Default case where there are no priority words
         template <typename Words>
         struct PriorityFuser {};

src/dsl/fusion/has_nuclear_dsl_method.hpp

@@ -0,0 +1,60 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2024 NUClear Contributors
+ *
+ * This file is part of the NUClear codebase.
+ * See https://github.com/Fastcode/NUClear for further info.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated
+ * documentation files (the "Software"), to deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
+ * WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+ * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#ifndef NUCLEAR_DSL_FUSION_FUSION_HAS_NUCLEAR_DSL_METHOD_HPP
+#define NUCLEAR_DSL_FUSION_FUSION_HAS_NUCLEAR_DSL_METHOD_HPP
+
+#include "NoOp.hpp"
+
+/**
+ * This macro to create an SFINAE type to check for the existence of a NUClear DSL method in a given class.
+ *
+ * The macro generates a template struct that can be used to determine if a class contains a specific method.
+ *
+ * The macro works by attempting to instantiate a function pointer to the method in question.
+ * If the method exists, the instantiation will succeed and the struct will inherit from
+ * `std::true_type`. Otherwise, it will inherit from `std::false_type`.
+ *
+ * @note This macro assumes that the method being checked for is a template method that can be instantiated with
+ * `ParsedNoOp`.
+ */
+// If you can find a way to do SFINAE in a constexpr for a variable function name let me know
+// NOLINTNEXTLINE(cppcoreguidelines-macro-usage)
+#define HAS_NUCLEAR_DSL_METHOD(Method)                                                 \
+    template <typename Word>                                                           \
+    struct has_##Method {                                                              \
+    private:                                                                           \
+        template <typename R, typename... A>                                           \
+        static auto test_func(R (*)(A...)) -> std::true_type;                          \
+        static auto test_func(...) -> std::false_type;                                 \
+                                                                                       \
+        /* Parenthesis would literally break this code*/                               \
+        template <typename U> /* NOLINTNEXTLINE(bugprone-macro-parentheses) */         \
+        static auto test(int) -> decltype(test_func(&U::template Method<ParsedNoOp>)); \
+        template <typename>                                                            \
+        static auto test(...) -> std::false_type;                                      \
+                                                                                       \
+    public:                                                                            \
+        static constexpr bool value = decltype(test<Word>(0))::value;                  \
+    }
+
+#endif  // NUCLEAR_DSL_FUSION_FUSION_HAS_NUCLEAR_DSL_METHOD_HPP