Path: not-for-mail
From: Terje Mathisen <terje.mathisen@tmsw.no>
Newsgroups: comp.arch
Subject: Re: Computer architects leaving Intel...
Date: Wed, 4 Sep 2024 09:15:19 +0200
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In-Reply-To: <vb8587$3gq7e$1@dont-email.me>

David Brown wrote:
> On 03/09/2024 18:54, Stephen Fuld wrote:
>> On 9/2/2024 11:23 PM, David Brown wrote:
>>> On 02/09/2024 18:46, Stephen Fuld wrote:
>>>> On 9/2/2024 1:23 AM, Terje Mathisen wrote:
>=20
>>>>> Anyway, that is all mostly moot since I'm using Rust for this kind =

>>>>> of programming now. :-)
>>>>
>>>> Can you talk about the advantages and disadvantages of Rust versus C=
?
>>>>
>>>
>>> And also for Rust versus C++ ?
>>
>> I asked about C versus Rust as Terje explicitly mentioned those two=20
>> languages, but you make a good point in general.
>>
>=20
> I want to know about both :-)
>=20
> In my field, small-systems embedded development, C has been dominant fo=
r=20
> a long time, but C++ use is increasing.=C2=A0 Most of my new stuff in r=
ecent=20
> times has been C++.=C2=A0 There are some in the field who are trying ou=
t=20
> Rust, so I need to look into it myself - either because it is a better =

> choice than C++, or because customers might want it.
>=20
>=20
>>
>>> My impression - based on hearsay for Rust as I have no experience -=20
>>> is that the key point of Rust is memory "safety".=C3=82=C2=A0 I use=20
>>> scare-quotes here, since it is simply about correct use of dynamic=20
>>> memory and buffers.
>>
>> I agree that memory safety is the key point, although I gather that it=
=20
>> has other features that many programmers like.
>>
>=20
> Sure.=C2=A0 There are certainly plenty of things that I think are a bet=
ter=20
> idea in a modern programming language and that make it a good step up=20
> compared to C.=C2=A0 My key interest is in comparison to C++ - it is a =
step=20
> up in some ways, a step down in others, and a step sideways in many=20
> features.=C2=A0 But is it overall up or down, for /my/ uses?
>=20
> Examples of things that I think are good in Rust are making variables=20
> immutable by default and pattern matching.=C2=A0 Steps down include lac=
k of=20
> function overloading and limited object oriented support.
>=20
> There are some things that some people really like about Rust, that I a=
m=20
> far from convinced about - such as package management.=C2=A0 I could be=
=20
> misunderstanding (since I don't have the experience), but for /my/ work=
,=20
> I am very much against anything that encourages an "always get the=20
> latest version" attitude.=C2=A0 Stability is much more important to me.=
=C2=A0 (I=20
> dislike the rate at which Rust changes - every two weeks or so for smal=
l=20
> things, and every couple of years for breaking changes.)

That's yet another of the things cargo (the rust package manager, as=20
well as lots of other stuff) get right:

Yes, by default you'll pick up the latest of every package/module you=20
"cargo add foo" to your project, but then you can edit the resulting=20
text-format configuration file, and lock down exact versions of some or=20
all of those packages.

This is similar to how we always freeze python packages: Any changes are =

something we decide to employ.


>=20
> And there are some things that Rust simply gets wrong - such as the=20
> handling of signed integer overflows.

Maybe?

Rust will _always_ check for such overflow in debug builds, then when=20
you've determined that they don't occur, the release build falls back=20
standard CPU behavior, i.e. wrapping around with no panics.

You can argue both pro and con here, personally I like the Rust setup=20
much more than C(++) which will use code that could do so as an excuse=20
to elide that as well as all surrounding/dependent code.

Terje

--=20
- <Terje.Mathisen at tmsw.no>
"almost all programming can be viewed as an exercise in caching"