I think it’s just that this is possible in (the recently released) Julia 1.9 and wasn’t possible in earlier versions due to how thread-local storage and the GC worked, and doing this can be useful sometimes.

I think the title was intended to be more playful and fun than a serious take on the most technically intense applications of threading in C++.

Your link 0 is cool, but is fairly different from the new stuff here. Some key differences are that the paper uses a conservative garbage collector (so enjoy random memory leaks) as a way to get around the problems of interop with C. Also, while that paper supports multithreading, as far as I can tell, it meant n-thread to 1 core (i.e. concurrent) multithreading (which is what the term usually referred to before multicore cpus were common), while Julia supports n threads to m cores (see Java's long awaited project Loom) which has a bunch of additional challenges. The last thing to mention is that the paper required a near complete rewrite of the lisp compiler. While that's an option for a simple language like Lisp, it's not as feasible for more complicated languages.

I recognized your nick from another Julia article. Why do you always have that condescending tone when commenting on something related to Julia?