In my Railroad Tycoon implementation , I have a function call tree that’s quite heavy : I loop over every train, updating each one (position is updated mutably for performance), and some trains will be entering important decision points or stations, so if I want to keep things functional (and I do), I…

To my understanding at runtime you cannot tell between tuples and records. It is all contiguous region of memory with the block tag. That’s what I get from playing some time ago with C FFI bindinds. This is a good read on this topic - Representation of OCaml data types

You can try this to convince yourself type a = int * int;; type b = { x: int; y : int };; external conv : a -> b = "%identity";; let p = conv (2, 2);; let _ = Printf.printf "{ x = %d; y = %d }\n" p.x p.y;;

[image] bluddy: Also, how does flambda treat this matter? Flambda can remove local tuple or record allocations, but is stuck at function boundaries. You can use inlining to remove a few such boundaries, but you will probably not manage to remove all allocations with that. On the other hand, …

[image] bluddy: Since this loop is called very often, I would prefer for it to be performant. Orthogonal to your questions, but have you actually benchmarked your code to gauge whether it needs to be more “performant”? Cheers, Nicolas

Returning large tuples vs records

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Zeta June 4, 2025, 2:37pm 5

Also labeled tuples are on their way: First alpha release of OCaml 5.4.0!

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Returning large tuples vs records

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