Question

So I currently have some code similar to this:

(Note: not actual code, just pared down from a somewhat long and complex method for brevity.)

template<typename ArgT0, typename ArgT1, typename FuncT>
static void addMethod( const std::string& name, FuncT func )
{
   Method script_func = [&]( const Arguments& args ) -> Value
   {
      func(UnsafeAnyCast<ArgT0>(args[0]),UnsafeAnyCast<ArgT1>(args[1]));
      return Value::Undefined();
   }

   _prototype->Set( name, script_func );
}

It works fine in Visual Studio 2010, but I know that is far from any guarantee that it is standard compliant C++. Is there anything wrong with this as far as using the template arguments inside the lambda?

Answer 1

Yes, this is standard compliant: a lambda expression has access to all the visible names in its enclosing scope, it’s only variables that you need to capture

5.1.2 Lambda expressions [expr.prim.lambda]

9 A lambda-expression whose smallest enclosing scope is a block scope
(3.3.3) is a local lambda expression; any other lambda-expression
shall not have a capture-list in its lambda-introducer. The reaching
scope of a local lambda expression is the set of enclosing scopes up
to and including the innermost enclosing function and its parameters