From 0729f0166c0dd6b4d4ed7697238406b2f8fd8a7b Mon Sep 17 00:00:00 2001
From: Rowan Goemans <goemansrowan@gmail.com>
Date: Thu, 26 Sep 2024 18:24:59 +0200
Subject: [PATCH] nextpnr_base_types: Add overload lambda visitor helper

---
 common/kernel/nextpnr_base_types.h | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/common/kernel/nextpnr_base_types.h b/common/kernel/nextpnr_base_types.h
index 80a0e24e..4f0d37fb 100644
--- a/common/kernel/nextpnr_base_types.h
+++ b/common/kernel/nextpnr_base_types.h
@@ -29,11 +29,27 @@
 
 #include <boost/functional/hash.hpp>
 #include <string>
+#include <variant>
 
 #include "hashlib.h"
 #include "idstring.h"
 #include "nextpnr_namespaces.h"
 
+/* Helper struct to overload lambdas for variabt visiting
+   so you can do:
+    std::variant<int, std::string> var = 42;
+
+    std::visit(overloaded{
+        [](int arg) { std::cout << "Integer: " << arg << '\n'; },
+        [](const std::string& arg) { std::cout << "String: " << arg << '\n'; }
+    }, var);
+*/
+template <class... Ts> struct overloaded : Ts...
+{
+    using Ts::operator()...;
+};
+template <class... Ts> overloaded(Ts...) -> overloaded<Ts...>;
+
 NEXTPNR_NAMESPACE_BEGIN
 
 struct GraphicElement