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This comment and parent comment don't appear to have read the article. It's specifically targetting C++ compatibility, that means compatible threading model, me

by baobob 4y ago

This comment and parent comment don't appear to have read the article. It's specifically targetting C++ compatibility, that means compatible threading model, memory model, ABI, type system, ... Rust has none of these. For every line of Rust code in the world, there are likely 10e3 - 100e3 lines of C++. You can either label it all "legacy code" and pretend your employer has the budget or time to rewrite it all, or you can find something in between writing new "legacy code", or throwing away your (for a company like Google) absolutely huge investment. FWIW projects that build for interoperability have a much higher chance of long term success than those that don't. This is true for everything in software, not just programming languages. For this reason alone you can't easily compare Carbon and Rust. Carbon sounds something a little closer to Vala (C compatibility) than anything like Rust

pipeline_peak 4y ago
You didn't appear to read my comment, I'm talking about compatibility with Rust and all these other look alike languages. Also your Vala comparison would imply this language compiles to C++.
- hiq 4y ago
  If they manage to make Carbon highly compatible with C++ (which is one of the design goals IIUC), then a C++/Rust compatibility layer should work fine with Carbon/Rust, or am I missing something? That's a big "if" of course, and time will tell whether they manage to pull it off, but at least that seems to be where they want to go.
  - pipeline_peak 4y ago
    Rust is already in production, I don’t think they take a different approach to compatibility.
    - hiq 4y ago
      The same approach to compatibility with C++? Can you use Rust as successor language in a C++ codebase, just like Typescript in a Javascript codebase? From my (limited) understanding that's not as straightforward, and other sources online seem to agree with this (e.g. see comments in https://old.reddit.com/r/rust/comments/w2tygg/carbon_language_an_experimental_successor_to_c/ https://old.reddit.com/r/rust/comments/w2tygg/carbon_languag...). The way I see it, Carbon has C++ compatibility as a requirement, adding as much safety, performance etc. as possible on top, while Rust seems to start from a safe-by-default approach and building its way from there.
    - baobob 4y ago
      From experience binding some Rust and C++ is not a trivial task. The introduction of Rust ownership and lifetimes alone means this always involves new design, even just to provide something approaching a 1:1 mapping to an existing API. True 1:1 mappings at least in my experience simply aren't possible, there is always some contortion required to reduce the freedom+unsafety exported by C
est31 4y ago
Google rewrites a lot of their software components from scratch every few years, at least according to section 2.11 of this paper: https://arxiv.org/pdf/1702.01715.pdf https://arxiv.org/pdf/1702.01715.pdf
- UncleMeat 4y ago
  I only run one team, but this is not my experience at Google whatsoever. Some stuff gets rewritten but this is not planned and is largely due to catastrophic changes in requirements or very bad initial designs.
brightball 4y ago
My mistake. Thank you for clarifying.

by baobob 4y ago

pipeline_peak 4y ago

You didn't appear to read my comment, I'm talking about compatibility with Rust and all these other look alike languages. Also your Vala comparison would imply this language compiles to C++.

hiq 4y ago
If they manage to make Carbon highly compatible with C++ (which is one of the design goals IIUC), then a C++/Rust compatibility layer should work fine with Carbon/Rust, or am I missing something? That's a big "if" of course, and time will tell whether they manage to pull it off, but at least that seems to be where they want to go.
- pipeline_peak 4y ago
  Rust is already in production, I don’t think they take a different approach to compatibility.
  - hiq 4y ago
    The same approach to compatibility with C++? Can you use Rust as successor language in a C++ codebase, just like Typescript in a Javascript codebase? From my (limited) understanding that's not as straightforward, and other sources online seem to agree with this (e.g. see comments in https://old.reddit.com/r/rust/comments/w2tygg/carbon_language_an_experimental_successor_to_c/ https://old.reddit.com/r/rust/comments/w2tygg/carbon_languag...). The way I see it, Carbon has C++ compatibility as a requirement, adding as much safety, performance etc. as possible on top, while Rust seems to start from a safe-by-default approach and building its way from there.
  - baobob 4y ago
    From experience binding some Rust and C++ is not a trivial task. The introduction of Rust ownership and lifetimes alone means this always involves new design, even just to provide something approaching a 1:1 mapping to an existing API. True 1:1 mappings at least in my experience simply aren't possible, there is always some contortion required to reduce the freedom+unsafety exported by C

est31 4y ago

Google rewrites a lot of their software components from scratch every few years, at least according to section 2.11 of this paper: https://arxiv.org/pdf/1702.01715.pdf https://arxiv.org/pdf/1702.01715.pdf

UncleMeat 4y ago
I only run one team, but this is not my experience at Google whatsoever. Some stuff gets rewritten but this is not planned and is largely due to catastrophic changes in requirements or very bad initial designs.

brightball 4y ago

My mistake. Thank you for clarifying.