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> C++ programmer (ideal Rust learner) Well there's your problem. Rust does look like a semi-colon language, that's intentional, but if that's all you understan

> C++ programmer (ideal Rust learner) Well there's your problem. Rust does look like a semi-colon language, that's intentional, but if that's all you understand you're probably going to struggle. The "ideal Rust learner" would have an ML, such as Ocaml or F#, maybe some Lisp or a Scheme something like that, as well as a semi-colon language like C or Java not just the weird forced perspective from C++ One experiment I probably won't get to try is to teach Rust as First Language for computer science students. Some top universities (including Oxbridge) teach an ML as first language, but neither teaches Rust because of course Rust is (relatively) new. The idea is, if you teach Rust as first language your students don't have to un-learn things from other languages. You can teach the move assignment semantic not as a weird special case but as it it really is in Rust - the obvious default assignment semantic. I pass a Goose to a function, obviously the Goose is gone, I gave it to the function. Nobody is surprised that when they pass a joint they don't have the joint any more, so why are we surprised when we pass a String to a function and the String is gone now? And once we've seen this, the motivation for borrows (reference types) is obvious, often we don't want to give you the string, we just want to tell you about a string that's still ours. And so on.

chipdart 2y ago
> Well there's your problem. Rust does look like a semi-colon language, that's intentional, but if that's all you understand you're probably going to struggle. This is a silly point to make. What makes a C++ programmer a C++ programmer is not an uncanny ability to find a semicolon on the keyboard. It's stuff like using low-level constructs, having a working mental model of how to manage resources at a low level down and how to pass and track ownership of resources across boundaries. This is not a syntax issue. It's absurd. You have people claiming that Rust is the natural progression for C++ programmers because their skillsets, mental models, and application domain overlap, but here are you negating all that and try to portray it as a semicolon issue?
- tialaramex 2y ago
  Oh! Alas the apparent syntax similarity is misleading. If you prefer imagine I wrote "C-like language" anywhere that I wrote "semi-colon language". It's not really about the semi-colon, indeed the semi-colon isn't even doing the same thing and that's a clue†. You see, the typical semi-colon languages you'll have used such as C++ or Java have these "everything is a machine integer" type systems which were a small step up from the "Who needs a type system" of their predecessors but aren't anywhere close to what you'd expect in an ML or a functional language. So this means there's a substantial learning curve, or, if you try to just keep writing C++ even though you're in Rust, an impedance mismatch. It looks superficially like the thing you're used to, but that's not what it is. † In Rust the semi-colon is turning your expression into a statement, but in the semi-colon languages it's a separator, everything is a statement anyway. So while a rust program might say let x = if k > 3 { plenty(k) } else { too_few() }; in the semi-colon languages there's a whole separate ternary operator provided to do this trick - in fact they don't have any other ternary operators and so they often call this "the" ternary operator which is very funny if you come from a language which has the multiply-accumulate operator...
- sfink 2y ago
  That's an... uncharitable interpretation of the phrase "semi-colon language". The comment made sense to me: it's not at all about semicolons, but the semicolon isn't a bad marker to distinguish between language families. It's closely related to expression- vs statement-focused languages, which if you squint is similar to the distinction between imperative and functional languages. Though the latter distinction is less relevant here, I'm just using it to point out that semicolon syntax is suggestive of semantics, even if it is itself just a superficial bit of syntax. You are correctly describing the awareness of resource management as an important characteristic, but that resource management is heavily intertwined with how values flow through the language syntax, which brings us back to expressions vs statements.

chipdart 2y ago

> Well there's your problem. Rust does look like a semi-colon language, that's intentional, but if that's all you understand you're probably going to struggle. This is a silly point to make. What makes a C++ programmer a C++ programmer is not an uncanny ability to find a semicolon on the keyboard. It's stuff like using low-level constructs, having a working mental model of how to manage resources at a low level down and how to pass and track ownership of resources across boundaries. This is not a syntax issue. It's absurd. You have people claiming that Rust is the natural progression for C++ programmers because their skillsets, mental models, and application domain overlap, but here are you negating all that and try to portray it as a semicolon issue?

tialaramex 2y ago
Oh! Alas the apparent syntax similarity is misleading. If you prefer imagine I wrote "C-like language" anywhere that I wrote "semi-colon language". It's not really about the semi-colon, indeed the semi-colon isn't even doing the same thing and that's a clue†. You see, the typical semi-colon languages you'll have used such as C++ or Java have these "everything is a machine integer" type systems which were a small step up from the "Who needs a type system" of their predecessors but aren't anywhere close to what you'd expect in an ML or a functional language. So this means there's a substantial learning curve, or, if you try to just keep writing C++ even though you're in Rust, an impedance mismatch. It looks superficially like the thing you're used to, but that's not what it is. † In Rust the semi-colon is turning your expression into a statement, but in the semi-colon languages it's a separator, everything is a statement anyway. So while a rust program might say let x = if k > 3 { plenty(k) } else { too_few() }; in the semi-colon languages there's a whole separate ternary operator provided to do this trick - in fact they don't have any other ternary operators and so they often call this "the" ternary operator which is very funny if you come from a language which has the multiply-accumulate operator...
sfink 2y ago
That's an... uncharitable interpretation of the phrase "semi-colon language". The comment made sense to me: it's not at all about semicolons, but the semicolon isn't a bad marker to distinguish between language families. It's closely related to expression- vs statement-focused languages, which if you squint is similar to the distinction between imperative and functional languages. Though the latter distinction is less relevant here, I'm just using it to point out that semicolon syntax is suggestive of semantics, even if it is itself just a superficial bit of syntax. You are correctly describing the awareness of resource management as an important characteristic, but that resource management is heavily intertwined with how values flow through the language syntax, which brings us back to expressions vs statements.