Tell HN: We are trying to get tail calls into the WebAssembly standard

I'm working on a relational stream processor and this is pretty critical to making it work well. a runtime standard with support for network connections would be nice too, but lets not get greedy

I am unsure, but I can make a guess. The first release of Wasm has been always considered a Minimum Viable Product, which a strong emphasis on Minimum. Pretty much only features already part of the legacy asm.js "standard" made the cut.

The fact that WebKit had some level of support for tail calls on the JS side is exactly the reason we choose it as the right platform to invest in.

The standard mandates it, and the V8 team implemented it, shipped it behind a flag, then unshipped based on reasons that initially seemed and ultimately were proven fuddy, when WebKit shipped PTC, and the world didn’t fall down.

The reason actual why it was withdrawn is that it would have required expensive changes to Microsoft’s Chakra (the calling conventions were incompatible).

Then Edge died... and Google didn’t add it back. Go figure.

Firefox also has problems implementing cross-realm tail calls. That could be spec’ed around, but there’s no will to do so.

Recursion indeed can be useful when working with trees or graphs. However, I don't like using recursion instead of a loop, because you make reader to unroll your code in their head to understand what it really does. If you need to add two arrays of numbers, use loop or array addition, but don't use recursion as a replacement for a loop.

Sadly the article uses a poor example, writing a useless factorial function. I have never needed such a function in production code, and if I needed, I would write it using a loop. Using bad examples like this might create an impression that recursion is not useful in real code (which is wrong). It would be better if you have used an example that looks like real code and that would become less readable without recursion.

Sorry if I miss something obvious, but how is this not solvable by the compiler?

I'm a huge functional programming evangelist, but high-level stuff like this does not belong in a low level language bytecode like WASM.

Wasm should only care about two things: Security and Performance.

With the standard blowing up like crazy we'll get neither. Worse, we'll cemenent the current duopoly of browser engines, because we'll make it (again) so complex that no-one can create an alternative.

We shouldn't have GC, Exceptions or Tail calls in WASM, as long as the compiler can provide them.

What we should have is multi memory support and memory read permissions, because without them WASM lacks basic security primitives.[1]

Reference types maybe. But I've yet to see a convincing argument as to why they are absolutely necessary.

Everything else (as long as it can be done by the compiler) is just bloat.

1. https://www.usenix.org/conference/usenixsecurity20/presentat...