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Writing a website in Rust

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Re: Writing a website in Rust

#11

Post by s_kilk »

viraptor wrote: post #7
neverminder wrote: post #6

> Actually the compiler checks cover most of the things I’d normally unit-test, so this is probably the only non-trivial project I wrote without checks and I’m OK with that. This is interesting. First time I read about Rust I had this gut feeling that it's design might reduce the number of unit testing cases. Someone care to comment on that?

Just to add some context, here are the tests which I didn't write, but would in Python/Flask usually: - Proper behaviour if I don't pass a parameter. Not needed, because it's an explicit `Option ` which I have to handle. - Is results list constructed properly / what's the None-vs-empty behaviour. Not needed, `Vec ` is verified at type level and None is not possible. - What happens if various database functions don't…

I've had a similar experience writing web-apps in Scala.

The Option type alone handles so many cases which would otherwise require unit-tests in Python or another unityped language.

Re: Writing a website in Rust

#12

Post by viraptor »

ilaksh wrote: post #10

Here's something that most of you will probably learn the hard way: popularity and merit are not the same thing. Rust is very popular now. That doesn't mean it has a great design. One of the very first design decision/belief they made was "no code can perform with garbage collection". Well, garbage collection does cause quite a few performance problems, but that doesn't mean it can't work if you engineer it right. Pe…

If you're going to write a block of text like that, you could at least fact check the main premise. Rust had GC. They started off with GC, so it wasn't the very first decision that "no code can perform with garbage collection".

Here's a post about removing GC from core rust 2 years ago: http://pcwalton.github.io/blog/2013/06/02/removing-garbage-c...

Next: they didn't kill GC. They removed it from core, because rust is capable of having gc implemented as a library. Standard library still has two gc-enabled pointers - Rc and Arc. You can use them in current code to have garbage collected values.

Re: Writing a website in Rust

#13

Post by Manishearth »

neverminder wrote: post #6

> Actually the compiler checks cover most of the things I’d normally unit-test, so this is probably the only non-trivial project I wrote without checks and I’m OK with that. This is interesting. First time I read about Rust I had this gut feeling that it's design might reduce the number of unit testing cases. Someone care to comment on that?

This is true IME. There are a lot of things you don't need to check for. Some guaranteed by Rust. Others guaranteed by the APIs themselves; Rust gives you a lot of powerful tools for designing APIs with static checks. For example, if you return a Result, you don't need to check if the programmer forgot to handle a failure mode in your tests. The mode will be handled, or there will be an explicit panic.

Rust is harder to get to compile, but a lot of your boilerplate testcases go away. And if you design your API right, even higher-level guarantees can be provided statically.

A lot of times when writing Rust code in Servo I'll just ensure that stuff compiles, and then run the tests once before making a pull request. When contributing to python codebases I generally make smaller, incremental changes and run tests.

Edit: Just to clarify, this doesn't mean you should go all #yolo and abandon testing entirely. But (a) you can do so temporarily without adverse effects, and (b) once you start, you'll find that you only need to focus on the higher level tests.

Re: Writing a website in Rust

#14

Post by pcwalton »

ilaksh wrote: post #10

Here's something that most of you will probably learn the hard way: popularity and merit are not the same thing. Rust is very popular now. That doesn't mean it has a great design. One of the very first design decision/belief they made was "no code can perform with garbage collection". Well, garbage collection does cause quite a few performance problems, but that doesn't mean it can't work if you engineer it right. Pe…

> The very first design decision/belief they made was "no code can perform with garbage collection". Well, garbage collection does cause quite a few performance problems, but that doesn't mean it can't work if you engineer it right.

That's not Rust's philosophy. Garbage collection is great—when it makes sense to use it. Rust is designed to make garbage collection optional, following the way systems software has been designed for decades.

> Mozilla as an organization is not going to be capable of admitting they made a mistake with Servo/Rust and recoding it in Nim.

I've already gone over multiple times why Nim would not be a good fit for Servo (which is not to say that Nim is a bad language, just that it would not be a good fit for Servo).

Re: Writing a website in Rust

#15

Post by ilaksh »

viraptor wrote: post #12
ilaksh wrote: post #10

Here's something that most of you will probably learn the hard way: popularity and merit are not the same thing. Rust is very popular now. That doesn't mean it has a great design. One of the very first design decision/belief they made was "no code can perform with garbage collection". Well, garbage collection does cause quite a few performance problems, but that doesn't mean it can't work if you engineer it right. Pe…

If you're going to write a block of text like that, you could at least fact check the main premise. Rust had GC. They started off with GC, so it wasn't the very first decision that "no code can perform with garbage collection". Here's a post about removing GC from core rust 2 years ago: http://pcwalton.github.io/blog/2013/06/02/removing-garbage-c... Next: they didn't kill GC. They removed it from core, because rust i…

Ok thanks. It was not the first decision then, just one of the early main design decisions. I edited the text to reflect that.

Re: Writing a website in Rust

#16

Post by filsmick »

ilaksh wrote: post #10

Here's something that most of you will probably learn the hard way: popularity and merit are not the same thing. Rust is very popular now. That doesn't mean it has a great design. One of the very first design decision/belief they made was "no code can perform with garbage collection". Well, garbage collection does cause quite a few performance problems, but that doesn't mean it can't work if you engineer it right. Pe…

While I agree with some of your arguments, namely that "popularity and merit are not the same thing", I think saying that Mozilla is "trapped in a pseudo-C++ mindset" and that its new browser would ideally be written in Nim is plain wrong.

The fact that using Rust to write a simple website isn't very handy doesn't mean it's a bad language. Web development simply isn't its primary focus: this is a systems programming language we're talking about. The mere fact that it is being considered for writing web apps is impressive since Rust is supposed to be a better C++, not a better Ruby, Python or Node.js. Rust mainly emphasizes performance and safety. This means all the 'magic' that happens in a dynamic language is exposed to the programmer, and has a cost: the code is more verbose, and seemingly simple things are more complicated.

Re: Writing a website in Rust

#17

Post by filsmick »

viraptor wrote: post #12
ilaksh wrote: post #10

Here's something that most of you will probably learn the hard way: popularity and merit are not the same thing. Rust is very popular now. That doesn't mean it has a great design. One of the very first design decision/belief they made was "no code can perform with garbage collection". Well, garbage collection does cause quite a few performance problems, but that doesn't mean it can't work if you engineer it right. Pe…

If you're going to write a block of text like that, you could at least fact check the main premise. Rust had GC. They started off with GC, so it wasn't the very first decision that "no code can perform with garbage collection". Here's a post about removing GC from core rust 2 years ago: http://pcwalton.github.io/blog/2013/06/02/removing-garbage-c... Next: they didn't kill GC. They removed it from core, because rust i…

Rc and Arc aren't exactly GC types... they are just reference-counted pointers, Rc being akin to C++'s shared_ptr. I get that in a sense, this is garbage collection, but certainly not full-featured like the ones you find in other languages.

Re: Writing a website in Rust

#18

Post by ilaksh »

filsmick wrote: post #16
ilaksh wrote: post #10

Here's something that most of you will probably learn the hard way: popularity and merit are not the same thing. Rust is very popular now. That doesn't mean it has a great design. One of the very first design decision/belief they made was "no code can perform with garbage collection". Well, garbage collection does cause quite a few performance problems, but that doesn't mean it can't work if you engineer it right. Pe…

While I agree with some of your arguments, namely that "popularity and merit are not the same thing", I think saying that Mozilla is "trapped in a pseudo-C++ mindset" and that its new browser would ideally be written in Nim is plain wrong. The fact that using Rust to write a simple website isn't very handy doesn't mean it's a bad language. Web development simply isn't its primary focus: this is a systems programming…

The idea that you can't get something good without a trade-off involving something bad is a false belief, an over-generalization that is very popular among people from all walks of life, including, unfortunately, technologists. Trade-offs do exist, but even a sword in fact has many more than two aspects.

Re: Writing a website in Rust

#19

Post by steveklabnik »

filsmick wrote: post #17
viraptor wrote: post #12

Earlier quoted context omitted.

If you're going to write a block of text like that, you could at least fact check the main premise. Rust had GC. They started off with GC, so it wasn't the very first decision that "no code can perform with garbage collection". Here's a post about removing GC from core rust 2 years ago: http://pcwalton.github.io/blog/2013/06/02/removing-garbage-c... Next: they didn't kill GC. They removed it from core, because rust i…

Rc and Arc aren't exactly GC types... they are just reference-counted pointers, Rc being akin to C++'s shared_ptr. I get that in a sense, this is garbage collection, but certainly not full-featured like the ones you find in other languages.

Refcounting and tracing are two different forms of GC, but you're right in the sense that most people mean tracing.

At the same time, we're putting a lot of thought into how to properly add an optional tracing GC. It's important that it doesn't impact the no-GC case, which is still, of course, primary.

Re: Writing a website in Rust

#20

Post by kybernetyk »

Well, IMHO, "the right hammer for the right nail".

Rust is a great systems language (besides the lack of bitfields) but I wouldn't use it as a web language. Just as much as I wouldn't use C++ to develop webapps.

Sure you can do it but then again there are far easier ways to achieve your goal.

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