[Sharlin]

The point is that, as mentioned in the article, the POSIX make spec is positively barren! Indeed, this is another example of very simple substitution systems turning out to be emergently Turing complete.

[d33]

So you'd say that it's a good thing? How is hidden complexity good?

[Sharlin]

It's not necessarily a good thing. It's definitely interesting, though. It's difficult to come up with systems that are simultaneously useful and don't have emergent complexity - and it's not clear to me if it's worth the effort to even try in the general case!

For what it's worth, in my opinion build systems should definitely be intentionally, not accidentally, Turing complete.

[Avshalom]

Eh, you pretty much have to specifically design systems to avoid turing completeness. It's a hilariously low bar to clear.