Hacker News

Swift at Apple: Migrating the TrueType hinting interpreter

62 points by DASD 3 hours ago | 21 comments

pjmlp 2 hours ago

During the State of Platform keynote, on the subject of Swift adoption across macOS, several examples were given, not only TrueType engine.

RIS is happening across all OS levels, if the keynote is to be believed.

DASD 2 hours ago

Curious the direction of Webkit as there was a nebulous mention of select portions being rewritten from C++ to Swift. And yet, the new ECMAScript module (ESM) loader for Safari 27 is implemented in C++ (https://webkit.org/blog/17967/news-from-wwdc26-webkit-in-saf...).

pjmlp 38 minutes ago

No idea, maybe the private parts of the code, Safari isn't open source, or is coming later.

In any case I would have liked to have more info during the deep dive sessions.

As it is, Meet with Apple on security (a 5h long event) had much more information.

weinzierl 48 minutes ago

Back in 2023 there was talks about Microsoft rewriting the font stuff in Rust for similar reasons Apple is now doing the Swift move.

I'm not sure what became of it and if it ever shipped. If anyone knows I'd be curious.

DASD 19 minutes ago

Russinovitch (Azure's CTO/CISO) gave a speech at RustConf 2025 and mentions it(DirectWriteCore) took 2 engineers 6 months resulting in 154K LOC and 5-15 percent performance increase for font shaping. https://www.youtube.com/watch?v=uDtMuS7BExE&list=PL2b0df3jKK...

saagarjha 59 minutes ago

Interesting that this is published under the MIT, rather than Apple’s more favorite Apache 2, license

JumpCrisscross 43 minutes ago

Why is it interesting?

drob518 39 minutes ago

Presumably because MIT is even more permissive and it’s a change in Apple’s behavior.

airstrike 33 minutes ago

As much as I enjoyed Swift, one can only wonder what the world would look like if they had gone with Rust as their default language instead.

jadengeller 20 minutes ago

Modern Swift borrows a lot from Rust! And it also has its own benefits, both ergonomic and also supporting eg generic in dynamic libraries

ecshafer 27 seconds ago

Swift and Rust were developed at similar times. I think of them more as having similar influences than borrowing from each other.

airstrike 10 minutes ago

[delayed]

vardump 9 minutes ago

Does it borrow borrow checker?

mrpippy 57 minutes ago

The author discussed this a bit on Mastodon as well:

https://xoxo.zone/@numist/116716469017975106

numist 19 minutes ago

I'm also here :)

LoganDark 43 minutes ago

I'm surprised the code has visible LLM smells. Though, I shouldn't be surprised. I hope the important bits are still human-controlled (and the same for Apple's many operating systems that absolutely deserve to remain stable and understood).

airspeedswift 31 minutes ago

I assure you, every inch of the interpreter code has been stared at by humans, a lot. TBH even the assembly generated by it has.

dgellow 41 minutes ago

From what I got Apple is using claude code A LOT internally

Cassell 4 minutes ago

It would be interesting to see their internal guidance on LLM use. It’s a massive amount of new power that has to be wielded carefully. That kind of guidance might mean the survival or downfall of some big corps in the next few years.

wahnfrieden 34 minutes ago

Yes they are using Claude Code - not the Xcode agents.

It worries me. I hope Codex adoption picks up there.

troupo 2 hours ago

I think these are the types of things Apple should've focused on instead of half-heartedly barging ahead with SwiftUI and breaking the language in the process

saagarjha 2 hours ago

I mean they’re doing both