A new C++ back end for ocamlc

(github.com)

161 points | by glittershark 8 hours ago

8 comments

  • QuadmasterXLII 7 hours ago
    Brilliant 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)))
    
    Whoever has to maintain your code after you are gone will apprrciate that you used the idiomatic, portable approach instrad of relying on command line flags.
  • anitil 2 hours ago
    > 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!

  • zorobo 6 hours ago
    This made my day, thank you!
  • dnmc 6 hours ago
    Is this the Stephen Dolan of "mov is Turing Complete" fame?
    • dolmen 8 minutes ago
      Is this the Stephen Dolan creator of jq?

      https://jqlang.org/

      • dkersten 2 minutes ago
        Going by the GitHub user, this seems to be the answer, yes. It makes sense, I believe he studied type theory or something related in the past.
    • loeg 5 hours ago
      I believe so.
  • ajbt200128 1 hour ago
    Wow Stephen Dolan never fails to impress
  • Caum 3 hours ago
    [flagged]
    • tux3 34 minutes ago
      This account is low-effort spam, the LLM generated comment seems to only look at the title. They should at least feed the contents of the page to the AI if they're going to spam.
    • fayash 1 hour ago
      Might have missed the joke here. This isn't a traditional C++ backend; it's a C++ Template Metaprogramming backend. The code isn't meant to be run—it’s meant to be compiled. The "output" you see is actually just a compiler error message because the program forces the compiler to calculate primes during type checking. The "runtime performance" the author mentioned is actually just how long g++ takes to crash your ram.
    • kristjansson 2 hours ago
      Per TFA C++ is a purely functional, interpreted language. Should be trivial to embed into?
  • hudsonhs 6 hours ago
    She (Jane Street) is not gonna notice you, bro