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Comment by thurn | Hacker News Reader

I love using Rust, but I also get a bit annoyed by the hype. It's absolutely true, for example, that there are highly useful programming patterns that are extremely difficult to express without tools like garbage collection -- including many classical ideas from functional programming. But Rust users sometimes give you the impression that wanting to write any code which doesn't fit the specific shape the borrow checker expects is morally wrong.

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Does using Rc or Arc feel morally wrong?

Having shared mutable state, or doing bare pointer arithmetics is "morally wrong" in the sense that it's a constant source of bugs in production, sometimes dangerous. Any language that reminds you about that is doing a useful thing; C++ is very much capable of that, too.

Meh, bare pointer arithmetic (and shared mutability, for that matter) can be quite morally OK if it's properly isolated to a self-contained module, with detailed specifications on its behavior. That's why Rust has an `unsafe` facility. It's morally wrong to use it across modules (because it's obviously non-compositional), but that's not what Rust devs are doing. This is not C/C++.

And good OOP is exactly about encapsulating that mutable part.

It's a bit silly to say shared mutable state is morally wrong. Rust programs have shared mutable state in that indices often refer to mutable data, and Java programs allow more conventional shared mutability without memory unsafety.

Shared mutability can enable some bugs, like the existence of a CPU enables bugs, but that doesn't mean CPUs are morally wrong.

Raw shared mutability is a mine field the moment mutations that depend on the current state occur.

If incrementing doesn't always increment you are in for a bad time after all.

You are always going to have data that is shared and changes. Any non trivial system will. Rust just discourages the naive "just point to the heap" method that tends to work until it doesn't.

Except Rust can only help when the heap being pointed to isn't shared across processes, possiblity written in multiple languages, e.g. NUMA shared memory.

If you do a crazy enough thing it will break isn't material to my statement "naively accessing the heap as if that is thread safe is bad anyway".

>is morally wrong

That is the problem not just with Rust but with today's tech. There is moral story or ideology everywhere. My definition of "engineers" is basically trade offs. Unfortunately that doesn't seems to happen much in software. The Rust Evangelism Strike Force.

Huh? "Morally" here is just shorthand for "practically, as a rule of thumb, for most intents and purposes" - it is the opposite of "morally correct". There are solid technical reasons for these concerns although they're a bit tedious to describe in detail (which is why we resort to these rules of thumb); they're not arbitrary or "ideological".

>Huh? "Morally" here is just shorthand for "practically, as a rule of thumb, for most intents and purposes"

There was an era when any rust code that use Unsafe is considered "morally wrong" regardless of whatever technical reasons or personal preference.

The brouhaha about Rust Unsafe was about code that used it where it was not needed (because you could write safe code that would optimize to the same thing), or used it incorrectly (not marking code that was only conditionally "safe", thus exporting unsafety to "safe" code potentially across Rust modularity boundaries.) And the actual issues got resolved rather quickly.

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