[3rdparty] Update pybind11, set a proper commit for libcoap, add a ty…

…pe_if helper

cmake/deps/coap.cmake

@@ -21,7 +21,7 @@ if(NOT TARGET libcoap::coap-3)
     FetchContent_Declare(
       libcoap
       GIT_REPOSITORY "https://github.com/obgm/libcoap"
-      GIT_TAG develop
+      GIT_TAG main
       GIT_PROGRESS true
     )
 

src/ossia/dataflow/execution_state.hpp

@@ -59,6 +59,7 @@ struct OSSIA_EXPORT execution_state : public Nano::Observer
   {
     return m_devices_exec;
   }
+
   ossia::net::node_base* find_node(std::string_view name) const noexcept
   {
     for(auto dev : m_devices_exec)

src/ossia/detail/type_if.hpp

@@ -0,0 +1,56 @@
+#pragma once
+#include <utility>
+
+namespace ossia
+{
+
+template <typename T, bool Predicate>
+struct type_if;
+template <typename T>
+struct type_if<T, false>
+{
+  type_if() = default;
+  type_if(const type_if&) = default;
+  type_if(type_if&&) = default;
+  type_if& operator=(const type_if&) = default;
+  type_if& operator=(type_if&&) = default;
+
+  template <typename U>
+  type_if(U&&)
+  {
+  }
+  template <typename U>
+  T& operator=(U&& u) noexcept
+  {
+    return *this;
+  }
+};
+
+template <typename T>
+struct type_if<T, true>
+{
+  [[no_unique_address]] T value;
+
+  type_if() = default;
+  type_if(const type_if&) = default;
+  type_if(type_if&&) = default;
+  type_if& operator=(const type_if&) = default;
+  type_if& operator=(type_if&&) = default;
+
+  template <typename U>
+  type_if(U&& other)
+      : value{std::forward<U>(other)}
+  {
+  }
+
+  operator const T&() const noexcept { return value; }
+  operator T&() noexcept { return value; }
+  operator T&&() && noexcept { return std::move(value); }
+
+  template <typename U>
+  T& operator=(U&& u) noexcept
+  {
+    return value = std::forward<U>(u);
+  }
+};
+}