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0 pointsaratno7y ago0 comments

From “Design Decisions”[1]:

> JSON. The protocol for front-end / back-end communication, as well as between the back-end and plug-ins, is based on simple JSON messages. I considered binary formats, but the actual improvement in performance would be completely in the noise. Using JSON considerably lowers friction for developing plug-ins, as it’s available out of the box for most modern languages, and there are plenty of the libraries available for the other ones.

1: https://github.com/xi-editor/xi-editor/blob/master/README.md...

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nothrabannosir7y ago

So is it too slow or not?

raphlinus7y ago

We actually do get 60fps, but JSON parsing on the Swift side takes more than its share of total CPU load, affecting power consumption among other things. So (partly to address the trolls elsewhere in the thread), the choice of JSON does not preclude fast implementation (as the existence of simdjson proves), but it does make it dependent on the language having a performant JSON implementation. I made the assumption that this would be the case, and for Swift it isn't.

dilap7y ago

At some point though, isn't it maybe easier just to use an inherently more efficient format than trying to rely on clever implementations to save you?

I totally get json for public internet services where you want to have lots of consumers and using a more efficient format would be significant friction, but writing an editor frontend is a very large endeavor -- it seems like the extra work of adopting something more efficient than json (like flatbuffers or whatever) would really be in the noise.

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jchb7y ago

One of the other performant libraries in the comparison section of simdjson has a Swift wrapper: https://github.com/chadaustin/sajson. Haven't tried it, but one option would be to bring that up to date. Another option, now that Swift 5 strings use utf8 as a native encoding, it may be possible to write a fast Json parser in native Swift. Likely someone already has or is doing that.

pdpi7y ago

It's not a binary yes/no question.

Given equally-high quality JSON and binary serdes, JSON is sufficiently fast. Raphlinus is saying that Swift's built-in deserialiser is obnoxiously slow.

coldtea7y ago

Any reason not to just use a third party Swift JSON library?

roblabla7y ago

Xi has multiple components written in multiple languages. In the rust core, json de/serialization is not a problem, but swift is lacking a similar high-performance library.

anderspitman7y ago

I'm going off topic at this point but I'd think for a native app the main advantages of a binary format would be the static typing and code generation that come from using an IDL.

wwright7y ago

Rust (the language the Xi core is developed in) has static typing for JSON, as well as other serialization formats: https://github.com/serde-rs/json

anderspitman7y ago

I'm familiar with serde. It's an incredible project, but I wouldn't quite call it "static typing for JSON". You still have to unwrap the parse at some point. However, I will concede the point that if you have Rust on both sides then you'll get most of the benefits.

greglindahl7y ago

You can have a binary format that's self-describing. It's important to understand all of the independent parts that go into a format.

j / k navigate · click thread line to collapse

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nothrabannosir7y ago

So is it too slow or not?

raphlinus7y ago

dilap7y ago

At some point though, isn't it maybe easier just to use an inherently more efficient format than trying to rely on clever implementations to save you?

1 more reply

jchb7y ago

pdpi7y ago

It's not a binary yes/no question.

Given equally-high quality JSON and binary serdes, JSON is sufficiently fast. Raphlinus is saying that Swift's built-in deserialiser is obnoxiously slow.

coldtea7y ago

Any reason not to just use a third party Swift JSON library?

roblabla7y ago

Xi has multiple components written in multiple languages. In the rust core, json de/serialization is not a problem, but swift is lacking a similar high-performance library.

anderspitman7y ago

I'm going off topic at this point but I'd think for a native app the main advantages of a binary format would be the static typing and code generation that come from using an IDL.

wwright7y ago

Rust (the language the Xi core is developed in) has static typing for JSON, as well as other serialization formats: https://github.com/serde-rs/json

anderspitman7y ago

greglindahl7y ago

You can have a binary format that's self-describing. It's important to understand all of the independent parts that go into a format.

j / k navigate · click thread line to collapse