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What Firefox done makes sense, but it does not look good to the idea you can just rewrite in Rust function by function. A regex engine seems to me a thing that

What Firefox done makes sense, but it does not look good to the idea you can just rewrite in Rust function by function. A regex engine seems to me a thing that is easy to TDD, so I would expect if rewriting in Rust is that easy Firefox would rewrite the most dangerous parts in Rust already (I assume regex is used with untrusted input but I am clueless so i could be wrong). IMO the giant army of Rust fans should put their energy working on Firefox or donating to have Firefox rewriten before 2030, because the story that is heavily promoted is that you can rewrite shit in Rust super easy, function by function, etc but the reality is different.

zozbot234 6y ago
C code can be rewritten function-by-function, even programmatically via c2rust. C++ is a bit messier and even the FFI interoperability story wrt. Rust is not quite complete.
frenchy 6y ago
Firefox didn't choose the C++ regex implementation because rewriting pieces of code with well defined interfaces is hard. It was for a few reasons: 1) at the time they made the decision, there was no existing rust regex library that matched the way that JavaScript worked, 2) they didn't want to write their own/rewrite existing code because regex libraries are complicated beasts, 3) the C++ code is mature and well tested, so the primary benefit of a rust implementation would be more speed (because it's easier to safetly reason about shared data) they didn't think that optimizing the regex engine was a priority.
- simion314 6y ago
  It makes sense, I am still a bit disappointed (so is a subjective thing) hopefully the RIR crowd gets more rational and reads your explanation and see that is not so easy.
FuckButtons 6y ago
>. A regex engine seems to me a thing that is easy to TDD Why go to all that effort when the thing you need is already available? I don't think there are that many people that argue that everything, even the stuff that works fine and doesn't have issues, should be re-written just because rust exists.

zozbot234 6y ago

C code can be rewritten function-by-function, even programmatically via c2rust. C++ is a bit messier and even the FFI interoperability story wrt. Rust is not quite complete.

frenchy 6y ago

Firefox didn't choose the C++ regex implementation because rewriting pieces of code with well defined interfaces is hard. It was for a few reasons: 1) at the time they made the decision, there was no existing rust regex library that matched the way that JavaScript worked, 2) they didn't want to write their own/rewrite existing code because regex libraries are complicated beasts, 3) the C++ code is mature and well tested, so the primary benefit of a rust implementation would be more speed (because it's easier to safetly reason about shared data) they didn't think that optimizing the regex engine was a priority.

simion314 6y ago
It makes sense, I am still a bit disappointed (so is a subjective thing) hopefully the RIR crowd gets more rational and reads your explanation and see that is not so easy.

FuckButtons 6y ago

>. A regex engine seems to me a thing that is easy to TDD Why go to all that effort when the thing you need is already available? I don't think there are that many people that argue that everything, even the stuff that works fine and doesn't have issues, should be re-written just because rust exists.