As for syntax, note that as the author says:

> I do not have access yet to a true C++26 compiler. When C++26 arrive, we will have features such as ‘template for’ which are like ‘for’ loops, but for template metaprogramming. Meanwhile, I use a somewhat obscure ‘expand’ syntax.

In particular, regarding the most cryptic line:

[:expand(nonstatic_data_members_of(^^T, ctx)):] >> [&]<auto member>{

In fact, at least from what I know, `expand()` and this fancy use of `>>` aren't actually part of the standard (the standard proposal uses them as an temporary example in case other features didn't get in). The equivalent (I think) line with the C++26 approved features would be a bit more friendly:

template for (constexpr auto member : nonstatic_data_members_of(^^T, ctx)) {

So while it's still not the prettiest thing in the world and knowing C++, it surely will produce some eldritch metaprogramming abominations, the author's examples made it look slightly uglier than it actually is.