From 4e5730e1fcef150ce2f13f52a278890589ca96ad Mon Sep 17 00:00:00 2001
From: rtk0c <mail.tianyig@gmail.com>
Date: Fri, 16 Apr 2021 16:49:28 -0700
Subject: More work on workflows - WorkflowStep -> WorkflowNode - Added initial
 kinds of WorkflowNode's

---
 core/src/Utils/Macros.hpp  |  8 +++++++-
 core/src/Utils/RTTI.hpp    | 44 ++++++++++++++++++++++++++++++++++++++++++++
 core/src/Utils/Variant.hpp | 27 +++++++++++++++++++++++++++
 3 files changed, 78 insertions(+), 1 deletion(-)
 create mode 100644 core/src/Utils/RTTI.hpp
 create mode 100644 core/src/Utils/Variant.hpp

(limited to 'core/src/Utils')

diff --git a/core/src/Utils/Macros.hpp b/core/src/Utils/Macros.hpp
index cb949b2..ab846f4 100644
--- a/core/src/Utils/Macros.hpp
+++ b/core/src/Utils/Macros.hpp
@@ -1,6 +1,12 @@
-#pragma  once
+#pragma once
 
 #define CONCAT_IMPL(a, b) a##b
 #define CONCAT(a, b) CONCAT_IMPL(a, b)
 
 #define UNIQUE_NAME(prefix) CONCAT(prefix, __LINE__)
+
+#if defined(_MSC_VER)
+#	define UNREACHABLE __assume(false)
+#elif defined(__clang__) || defined(__GNUC__)
+#	define UUNREACHABLE __builtin_unreachable()
+#endif
diff --git a/core/src/Utils/RTTI.hpp b/core/src/Utils/RTTI.hpp
new file mode 100644
index 0000000..bc0d289
--- /dev/null
+++ b/core/src/Utils/RTTI.hpp
@@ -0,0 +1,44 @@
+#pragma once
+
+#include <cassert>
+
+template <class T, class TBase>
+bool is_a(TBase* t) {
+	assert(t != nullptr);
+	return T::IsInstance(t);
+}
+
+template <class T, class TBase>
+bool is_a_nullable(TBase* t) {
+	if (t) {
+		return is_a<T, TBase>(t);
+	} else {
+		return false;
+	}
+}
+
+template <class T, class TBase>
+T* dyn_cast(TBase* t) {
+	assert(t != nullptr);
+	if (T::IsInstance(t)) {
+		return static_cast<T*>(t);
+	} else {
+		return nullptr;
+	}
+}
+
+template <class T, class TBase>
+const T* dyn_cast(const TBase* t) {
+	assert(t != nullptr);
+	if (T::IsInstance(t)) {
+		return static_cast<const T*>(t);
+	} else {
+		return nullptr;
+	}
+}
+
+template <class T, class TBase>
+T* dyn_cast_nullable(TBase* t) {
+	if (!t) return nullptr;
+	return dyn_cast<T, TBase>(t);
+}
diff --git a/core/src/Utils/Variant.hpp b/core/src/Utils/Variant.hpp
new file mode 100644
index 0000000..7fdb2dc
--- /dev/null
+++ b/core/src/Utils/Variant.hpp
@@ -0,0 +1,27 @@
+#pragma once
+
+#include <utility>
+#include <variant>
+
+template <class... Ts>
+struct Overloaded : Ts... { using Ts::operator()...; };
+template <class... Ts>
+Overloaded(Ts...) -> Overloaded<Ts...>;
+
+template <class... Args>
+struct VariantCastProxy {
+	std::variant<Args...> v;
+
+	template <class... ToArgs>
+	operator std::variant<ToArgs...>() const {
+		return std::visit(
+			[](auto&& arg) -> std::variant<ToArgs...> { return arg; },
+			v);
+	}
+};
+
+/// Use snake_case naming to align with `static_cast`, `dynamic_cast`, etc..
+template <class... Args>
+auto variant_cast(std::variant<Args...> v) -> VariantCastProxy<Args...> {
+	return { std::move(v) };
+}
-- 
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