5 ms·

If it's an effective solution it will only seem weird until it's proven to be more useful than the status quo approach. I read this post and thought 'async as

by ljm 8y ago

If it's an effective solution it will only seem weird until it's proven to be more useful than the status quo approach. I read this post and thought 'async as a prefix is intuitive!', but that's only because I saw it first in C#. Rust already has an immense learning curve despite its ergonomics, I say it should continue to experiment. Same way Haskell does. I do wonder if `.await` could have a sigil equivalent the same way `try!` did with `?`. `…` could work if it's not already used as spread args.

ajross 8y ago
> If it's an effective solution it will only seem weird until it's proven to be more useful than the status quo approach. Perl was a very effective solution. Still lost. And I say that as a long time perl5 nut. Rust is, indeed, just syntactically insane to a new learner (honestly, worse than perl ever was). And it's getting rapidly worse.
- username223 8y ago
  > Perl was a very effective solution. Still lost. For some version of "lost." It lost to $LANGUAGE_OF_THE_MOMENT for web development, but Perl is still a great text-munging and glue language, and I'll bet I'm not the only one using it for that. It didn't take over the world, but I'll bet that most people interact with a bit of Perl every day. I agree that Rust is syntactically insane. Worse, while a Shell-and-C programmer would have some intuition about Perl syntax, a C++ programmer will almost start from scratch in Rust.
- pcwalton 8y ago
  > Rust is, indeed, just syntactically insane to a new learner (honestly, worse than perl ever was). Can you elaborate?
  - ajross 8y ago
    Not even if you paid me to have that fight, no. Edit: OK, one tiny crumb: https://doc.rust-lang.org/book/ch06-01-defining-an-enum.html https://doc.rust-lang.org/book/ch06-01-defining-an-enum.html -- Read through that thinking about how other languages express the same fundamentally simple concepts, and consider how Rust invents new syntax for basically everything, and then sticks it all together by re-using syntax from other areas. Why does a parametrized enumerant look like a function call and not a struct? Why is "127.0.0.1" not a String? Why do parametrized enumerants look in rvalues like C++ constructor arguments, which you promised earlier Rust didn't have? Don't tell me the answers to those questions. I know the answers. Just recognize that those are questions that every new reader to that very early page in your docs is going to have. And... did they even need to be questions in the first place?
    - simias 8y ago
      You need to tell us which other language you compare it to then. AFAIK most mainstream languages (the ones these hypothetical new readers are most likely to come from) don't have anything like Rust's enums. C++ does have the difference between C-style "const char " and "std::string" which is a bit* similar to &str and String, although &str is obviously massively safer and more ergonomic. If they come from Scala or Haskell then yeah, sure but I'd argue that most programmers these days are likely to come from JS, Python or Java/C#/C++ and copying Scala or Haskell syntax would look even more foreign to them. Rust instead preferred to go for a syntax inspired by C++ >Don't tell me the answers to those questions. [...] And... did they even need to be questions in the first place? So you know the answers but you still think it shouldn't be done that way? Having things like &str instead of forcing everything into a dynamic String is Rust's killer feature. It means that you can write safe code while not being forced into adding any overhead. You pay for what you use, to quote the C++ motto. That means that as Rust matures it becomes a good competitor for replacing C and C++.
    - saghm 8y ago
      > Why does a parametrized enumerant look like a function call and not a struct? I don't think this is an "invented new syntax"; plenty of languages with built-in support for sum types do it this way. Of course, most mainstream languages don't have built-in support for sum types, but that's an entirely unrelated point to Rust's syntax for them.
    - pcwalton 8y ago
      > Why does a parametrized enumerant look like a function call and not a struct? Because tuples are considered good things to have in a modern language. Structs and enum variants are just named versions of tuples (denoted with parentheses) or records (denoted with braces—unnamed records don't exist in Rust). To follow languages like Python, they're written "(1, 2, 3)". (It would be weird if tuples were written "{1, 2, 3}", right?) Therefore, a tuple named Foo is written "Foo(1, 2, 3)". Removing tuples from the language was actually considered at one point, but the community (including me) really wanted them to stay, so they stayed. > Why is "127.0.0.1" not a String? Because it's a str, and there is a difference between str and String. Not having a string-view type would be a big mistake in a systems language like Rust. Note that "127.0.0.1" is not a std::string in C++ either (though there is an implicit constructor that can make it one). In fact, the reason why we have both "str" and "String" is precisely to address your criticism: if we named "str" "string_view" or something, then people would be really surprised that a literal like "127.0.0.1" isn't a string. > Why do parametrized enumerants look in rvalues like C++ constructor arguments, which you promised earlier Rust didn't have? Because saying Rust has C++ constructors would just make things more confusing, because then people would expect them to behave like C++ constructors. It's less confusing to say that Rust doesn't have constructors like C++ does. > And... did they even need to be questions in the first place? I don't see any alternatives to the above that would make the language better instead of worse.
  - foota 8y ago
    I'll bite. For context, I'm very much a rust beginner with probably a couple dozen hours at most. I find that anything having to do with lifetime parameters is hard. I think this is even worse than C++ templating in some sense since it behaves differently than type templating. Otherwise, I think the syntax is fairly reasonable.
    - estebank 8y ago
      My advice would be to completely forego lifetimes handling until much later in time. It is a difficult part of the language to master but it gets much easier once you get more practice. Get well acquainted with the rest of the language and you'll pick them up with less trouble.
    - pcwalton 8y ago
      That's legitimate; lifetime parameters are a new concept that aren't found in any other language. They naturally require a learning curve. Lifetime elision—making it so that you don't have to see lifetimes in most cases—is the main way we tried to make them easier.
  - zzzcpan 8y ago
    Perl was designed to be familiar to C programmers.
    - teddyh 8y ago
      No, Perl was designed to be familiar with Unix shell script (with its various variants), sed, and AWK programmers.
- simias 8y ago
  I've used perl5 for a long time (although these days I've replaced it with python in my toolchain, although I have my fair share of complaints about python as well) and I think your comparison is unfair. Rust's sometimes complicated syntax is made necessary by the very concept of the language. You need to be able to express lifetimes, you need to be able to express generics, you need to be able to strongly type lambdas etc... Of course the syntax is going to be a bit more complicated than, say, Common Lisp where everything is dynamic and garbage collected and you can let the runtime figure things out. Perl 5 was syntactically insane because that's how the authors decided to do it. Effectively it didn't let you express things that were impossible in Lisp, Python, Ruby or JS. It's just a design choice to lean heavily on sigils and magic variables to favor short code even if it can be cryptic to people not intimately familiar with the language. I doubt anybody who hasn't used perl before will be able to figure out exactly what this does (and I'd argue that it's a fairly simple and idiomatic script, not some heinously cryptic code golf): while (<>) { chomp(); s/f.o/bar/; print; } Rust is noisy because it has to represent concepts that simply don't exist in other programming languages. I'd go even further: Rust does a better job than most languages at letting you only explicitly mention things that need to be explicitly mentioned. Thanks to the very powerful type inference you can write very tidy code, IMO much more so than in C where I have to explicitly type every intermediary variable that I would use for instance.
  - ajross 8y ago
    > Rust is noisy because it has to represent concepts that simply don't exist in other programming languages. In a few cases having to do with lifetime management and the borrow checker, that's certainly true. But the example at hand is fundamentally just cloning ideas from Javascript.
    - majewsky 8y ago
      The point is not that particular feature. It's how this new feature interacts with a bunch of existing language features.
    - dbrgn 8y ago
      Actually JS just cloned those ideas from C# and Python.
childintime 8y ago
> 'async as a prefix is intuitive!', but that's only because I saw it first in C# The analogy made in the post, with the possibility of “expression-oriented” keywords like .match, suggests that `match expr {..}` is equivalent to `expr.match {..}`. So by analogy `await expr` and `expr.await` are also similar. So why was the "prefix await" syntax dismissed right out of the gate? It is the option that needs the best argumentation, because 1) it is familiar and 2) match is currently a prefix (keyword), so await could probably also be. Edit: only the await prefix clearly signals a break in control flow, only the prefix variant emphasizes this. In contrast the dot await syntax hides this.

by ljm 8y ago

ajross 8y ago

> If it's an effective solution it will only seem weird until it's proven to be more useful than the status quo approach. Perl was a very effective solution. Still lost. And I say that as a long time perl5 nut. Rust is, indeed, just syntactically insane to a new learner (honestly, worse than perl ever was). And it's getting rapidly worse.

username223 8y ago
> Perl was a very effective solution. Still lost. For some version of "lost." It lost to $LANGUAGE_OF_THE_MOMENT for web development, but Perl is still a great text-munging and glue language, and I'll bet I'm not the only one using it for that. It didn't take over the world, but I'll bet that most people interact with a bit of Perl every day. I agree that Rust is syntactically insane. Worse, while a Shell-and-C programmer would have some intuition about Perl syntax, a C++ programmer will almost start from scratch in Rust.
pcwalton 8y ago
> Rust is, indeed, just syntactically insane to a new learner (honestly, worse than perl ever was). Can you elaborate?
- ajross 8y ago
  Not even if you paid me to have that fight, no. Edit: OK, one tiny crumb: https://doc.rust-lang.org/book/ch06-01-defining-an-enum.html https://doc.rust-lang.org/book/ch06-01-defining-an-enum.html -- Read through that thinking about how other languages express the same fundamentally simple concepts, and consider how Rust invents new syntax for basically everything, and then sticks it all together by re-using syntax from other areas. Why does a parametrized enumerant look like a function call and not a struct? Why is "127.0.0.1" not a String? Why do parametrized enumerants look in rvalues like C++ constructor arguments, which you promised earlier Rust didn't have? Don't tell me the answers to those questions. I know the answers. Just recognize that those are questions that every new reader to that very early page in your docs is going to have. And... did they even need to be questions in the first place?
  - simias 8y ago
    You need to tell us which other language you compare it to then. AFAIK most mainstream languages (the ones these hypothetical new readers are most likely to come from) don't have anything like Rust's enums. C++ does have the difference between C-style "const char " and "std::string" which is a bit* similar to &str and String, although &str is obviously massively safer and more ergonomic. If they come from Scala or Haskell then yeah, sure but I'd argue that most programmers these days are likely to come from JS, Python or Java/C#/C++ and copying Scala or Haskell syntax would look even more foreign to them. Rust instead preferred to go for a syntax inspired by C++ >Don't tell me the answers to those questions. [...] And... did they even need to be questions in the first place? So you know the answers but you still think it shouldn't be done that way? Having things like &str instead of forcing everything into a dynamic String is Rust's killer feature. It means that you can write safe code while not being forced into adding any overhead. You pay for what you use, to quote the C++ motto. That means that as Rust matures it becomes a good competitor for replacing C and C++.
  - saghm 8y ago
    > Why does a parametrized enumerant look like a function call and not a struct? I don't think this is an "invented new syntax"; plenty of languages with built-in support for sum types do it this way. Of course, most mainstream languages don't have built-in support for sum types, but that's an entirely unrelated point to Rust's syntax for them.
  - pcwalton 8y ago
    > Why does a parametrized enumerant look like a function call and not a struct? Because tuples are considered good things to have in a modern language. Structs and enum variants are just named versions of tuples (denoted with parentheses) or records (denoted with braces—unnamed records don't exist in Rust). To follow languages like Python, they're written "(1, 2, 3)". (It would be weird if tuples were written "{1, 2, 3}", right?) Therefore, a tuple named Foo is written "Foo(1, 2, 3)". Removing tuples from the language was actually considered at one point, but the community (including me) really wanted them to stay, so they stayed. > Why is "127.0.0.1" not a String? Because it's a str, and there is a difference between str and String. Not having a string-view type would be a big mistake in a systems language like Rust. Note that "127.0.0.1" is not a std::string in C++ either (though there is an implicit constructor that can make it one). In fact, the reason why we have both "str" and "String" is precisely to address your criticism: if we named "str" "string_view" or something, then people would be really surprised that a literal like "127.0.0.1" isn't a string. > Why do parametrized enumerants look in rvalues like C++ constructor arguments, which you promised earlier Rust didn't have? Because saying Rust has C++ constructors would just make things more confusing, because then people would expect them to behave like C++ constructors. It's less confusing to say that Rust doesn't have constructors like C++ does. > And... did they even need to be questions in the first place? I don't see any alternatives to the above that would make the language better instead of worse.
- foota 8y ago
  I'll bite. For context, I'm very much a rust beginner with probably a couple dozen hours at most. I find that anything having to do with lifetime parameters is hard. I think this is even worse than C++ templating in some sense since it behaves differently than type templating. Otherwise, I think the syntax is fairly reasonable.
  - estebank 8y ago
    My advice would be to completely forego lifetimes handling until much later in time. It is a difficult part of the language to master but it gets much easier once you get more practice. Get well acquainted with the rest of the language and you'll pick them up with less trouble.
  - pcwalton 8y ago
    That's legitimate; lifetime parameters are a new concept that aren't found in any other language. They naturally require a learning curve. Lifetime elision—making it so that you don't have to see lifetimes in most cases—is the main way we tried to make them easier.
- zzzcpan 8y ago
  Perl was designed to be familiar to C programmers.
  - teddyh 8y ago
    No, Perl was designed to be familiar with Unix shell script (with its various variants), sed, and AWK programmers.
simias 8y ago
I've used perl5 for a long time (although these days I've replaced it with python in my toolchain, although I have my fair share of complaints about python as well) and I think your comparison is unfair. Rust's sometimes complicated syntax is made necessary by the very concept of the language. You need to be able to express lifetimes, you need to be able to express generics, you need to be able to strongly type lambdas etc... Of course the syntax is going to be a bit more complicated than, say, Common Lisp where everything is dynamic and garbage collected and you can let the runtime figure things out. Perl 5 was syntactically insane because that's how the authors decided to do it. Effectively it didn't let you express things that were impossible in Lisp, Python, Ruby or JS. It's just a design choice to lean heavily on sigils and magic variables to favor short code even if it can be cryptic to people not intimately familiar with the language. I doubt anybody who hasn't used perl before will be able to figure out exactly what this does (and I'd argue that it's a fairly simple and idiomatic script, not some heinously cryptic code golf): while (<>) { chomp(); s/f.o/bar/; print; } Rust is noisy because it has to represent concepts that simply don't exist in other programming languages. I'd go even further: Rust does a better job than most languages at letting you only explicitly mention things that need to be explicitly mentioned. Thanks to the very powerful type inference you can write very tidy code, IMO much more so than in C where I have to explicitly type every intermediary variable that I would use for instance.
- ajross 8y ago
  > Rust is noisy because it has to represent concepts that simply don't exist in other programming languages. In a few cases having to do with lifetime management and the borrow checker, that's certainly true. But the example at hand is fundamentally just cloning ideas from Javascript.
  - majewsky 8y ago
    The point is not that particular feature. It's how this new feature interacts with a bunch of existing language features.
  - dbrgn 8y ago
    Actually JS just cloned those ideas from C# and Python.

childintime 8y ago

> 'async as a prefix is intuitive!', but that's only because I saw it first in C# The analogy made in the post, with the possibility of “expression-oriented” keywords like .match, suggests that `match expr {..}` is equivalent to `expr.match {..}`. So by analogy `await expr` and `expr.await` are also similar. So why was the "prefix await" syntax dismissed right out of the gate? It is the option that needs the best argumentation, because 1) it is familiar and 2) match is currently a prefix (keyword), so await could probably also be. Edit: only the await prefix clearly signals a break in control flow, only the prefix variant emphasizes this. In contrast the dot await syntax hides this.