I find the article very interesting and informative but, honestly, of all of the approaches, I find the basic switch to be the most readable and likely the most maintainable, at least for this case.
One keeps the whole security discussion going on, while the other keeps an image that C++ is a language not worth learning.
C++ isn't great for for metaprogramming, because much of it is a hack that uses the type system to do things it was never originally designed to do (i.e. as a lisp). But as metaprogramming has become more commonplace, the language has evolved with features that make it easier and more readable. It's still all based on a hack, and there's still no good way to debug a metaprogram. But at least I don't have to read the loki book anymore to grok it.
I still prefer to use a proper code generator when I can (it compiles faster, and I can see the generated code). Generating an ordinary switch outside of C++ is certainly an option and is something I've done. But I don't reach for it every time, because those tools tend to be kludgy as well (they can generate invalid C++, which templates and comstexpr cannot).