A new C++ back end for ocamlc
github.comBrilliant stuff. A tip for writing long-running C++: bizzarely, the C++ interpreter completely lacks tail call optimization. As a result, most idiomatic C++ code implements and uses reverse, map, range, filter etc, which don’t blow the stack if you implement them like (forgive the pseudo-code)
(defun fibreverse (i ret acc)
(if acc
(if (> i 0)
(progn
(setv call1 (fibreverse (- i 1) (cons (head acc) ret) (tail acc)))
(setv ret1 (head call1))
(setv acc1 (head (tail call1)))
(if acc1
(fibreverse (- i 2) (cons (head acc1) ret1) (tail acc1))
(pair ret1 acc1)))
(pair ret acc))
(pair ret acc)))
(defun reverse (list) (head (fibreverse 30 nil list)))
> Using these more sophisticated data structures, g++ is able to compute the prime numbers below 10000 in only 8 seconds, using a modest 3.1 GiB of memory.
Finally, I can get some primes on my laptop!
> which produces primes.cpp, containing your program translated to idiomatic, readable C++ code:
As a C++ enjoyer I can confirm this is some excellent idiomatic, readable C++ code.
Most of it yes, but what about:
There is some top class wizardry going on there! I don’t think I’ve ever used conditions in a type definition in C++ :)typedef I<((I<((n::val (p::val))>::val) != (I<0>::val))> res; };Update:
Ah, alright - so that evaluation logic is part of the template, not the code that eventually compiles.
It’s basically offloading some of the higher level language compiler logic to the templating engine. Honestly might be a better time investment than spending more time writing this in the parser.
Now I’m sort of intrigued and inspired to use C++ as a lowering target for elevate (a compiler framework I’ve been working on).
Is this the Stephen Dolan of "mov is Turing Complete" fame?
I believe so.
This made my day, thank you!
My eyebrows raised at "C++ is a purely functional language", but I thought it was just a typo.
The rest is fantastic, and I'm glad it wasn't a typo.
> C++ is a purely functional language, with no support for mutable state.
> To run a C++ program, you'll need a C++ interpreter.
I thought 1. April is already over?
Wow Stephen Dolan never fails to impress
She (Jane Street) is not gonna notice you, bro
I believe they already work for Jane Street.
Interesting fact: it was recently "revealed" in a podcast episode by Bryan Cantrill that Jane Street was one of the early customer of the Oxide Computer company.