
Why I moved from Rust to simpler, cleaner C - FascinatedBox
http://fascinatedbox.blogspot.com/2017/04/why-im-moving-from-rust-to-c.html
======
gpm
This appears to be a april fools joke... judging by the Repo Lily was always
written in C [0].

[0]
[https://github.com/FascinatedBox/lily/tree/9ed9a706e0a1f99ff...](https://github.com/FascinatedBox/lily/tree/9ed9a706e0a1f99ff271cde132b73664e9bf3ff8)
(Tree at a random commit a while back)

~~~
i336_
Yep.

First commit:
[https://github.com/FascinatedBox/lily/commit/1e509cbdd56ef36...](https://github.com/FascinatedBox/lily/commit/1e509cbdd56ef36029c7cd30317025eeaffa47fe)

Commit list at oldest page:
[https://github.com/FascinatedBox/lily/commits/master?after=9...](https://github.com/FascinatedBox/lily/commits/master?after=95b7f2a6acdffcddd0a59c804990670c26acabb6+244)

(GH doesn't seem to have an easy way to jump around time and directly find
commits. I jumped to the oldest tag, went to the commit list, clicked "older",
edited the tag out of the URL then followed "older" to the start. Took around
15 clicks.)

------
buzzybee
I liked the part about the parser not benefitting from memory safety(parsers
are a classic source of CVEs).

------
starik36
I checked out the Lily tutorial ([https://fascinatedbox.github.io/lily-
site/tutorial.html](https://fascinatedbox.github.io/lily-site/tutorial.html))
and the syntax is unusually clean. Really cool!

------
hawkice
I mean, this is great, obviously. True spirit of the holiday.

That being said, rustc _is_ slow.

~~~
portmanteaufu
Happily, incremental compilation[1] is set to be included in the next
release[2] at the end of April!

[1] [https://github.com/rust-lang/rust/issues/2369](https://github.com/rust-
lang/rust/issues/2369)

[2] [https://internals.rust-lang.org/t/rust-release-milestone-
pre...](https://internals.rust-lang.org/t/rust-release-milestone-
predictions/4591)

------
bascule
I can't tell if this is an April Fool's joke or not. If it is,
congratulations, troll successful. But I'm going to go ahead and reply
anyway...

There are exactly two valid* points in this post:

    
    
        - rustc is slow
        - "the circlejerk"
    

* i.e. not completely without merit

I'll just go through these really quick:

1\. rustc is slow

Rust just shipped (in beta) incremental compilation, a technique commonly used
by compilers to speed up recompiles:

[https://internals.rust-lang.org/t/incremental-compilation-
be...](https://internals.rust-lang.org/t/incremental-compilation-beta/4721)

This doesn't change the fact rustc is slow, but it certainly makes the
developer experience much better. Try it out!

That said, rustc is still slow. A valid complaint.

2\. rust needs unions

Rust has two types of unions:

    
    
        - tagged unions a.k.a. sum types. These are preferred
        - #[feature(untagged_unions)]: actual C-style unions, unsafe, useful for C interop
    

You probably want the first kind. Rust does have them!

3\. linked lists are great

Linked lists are great! I use them in one of the main Rust programs I'm
working on. The thing about Rust linked lists is how you write one will depend
entirely on your memory model.

One of the best tutorials on Rust explains the language's memory model in
terms of linked lists. It's a great read, a harrowing tale of "fighting rustc"
until you achieve victory:

[http://cglab.ca/~abeinges/blah/too-many-
lists/book/](http://cglab.ca/~abeinges/blah/too-many-lists/book/)

I'm using immutable arena-allocated linked lists, which is a great pattern.
This is in conjunction with tagged unions, and together I have an immutable
sum type + list memory model for a sort of Lisp-alike VM.

I did have to implement my own linked lists. The code is not terribly
complicated. It'd be nice if there were standard one-size-fits-all linked
lists in e.g. the "collections" module, but the type system needs a bit more
work before it will be generic enough for that to be a good idea. Until then,
you'll have to write your own or use a library given your unique constraints.
But that's not really different from C...

4\. "the circlejerk" a.k.a. the community

If you dislike the community there's not a lot to say. It's probably a bad
idea to use a language whose community you dislike.

I personally think Rust has a great community.

5\. rust's safety is overrated

C programmers routinely make memory safety mistakes, even if they're experts,
even if they're using static analysis tools. You don't have to use Rust to
have a safe memory model... any JVM language or most other managed language
runtimes will do.

If you're writing a trivial C program it's possible it's safe. But it only
takes one mistake for things to go from safe to catastrophic in C.

~~~
charlieflowers
>> "together I have an immutable sum type + list memory model for a sort of
Lisp-alike VM"

So are you saying that you're using Rust as if it were a higher level
language? Almost as if you had garbage collection? (If so, that's very
interesting. I've been wondering about ways to do that when it's appropriate
for the task at hand).

~~~
bascule
No, I am using Rust to implement an interpreter for a Lisp-like language

------
yandrypozo
> "Every time there is a post on Hacker News or Reddit about a vulnerability
> in C, the strike team comes out to mention a rewrite in Rust"

I thought it was only happening with Go posts, but I can see it's happening
with C and C++ too, which other programming language do you know is suffering
Rust attacks ??

