4 ms·

> It's strict, yes, but most of that strictness helps with eliminating the types of errors that make your app break over and over again at runtime. Really? Mos

> It's strict, yes, but most of that strictness helps with eliminating the types of errors that make your app break over and over again at runtime. Really? Most throwaway-script errors I get are simple things like IO mistakes, mistyped URL, or logic errors. The rust borrow checker is not designed to catch simple mistakes, it's designed for massive multi-threaded applications, e.g. making sure threads access data safely, making sure a variable doesn't get unexpectedly modified by some other file, making sure memory is owned by exactly one place, etc. But in a single-threaded garbage collected script that can fit on your monitor, why should you care? The borrow checker does not check for logic errors; it checks for the things you don't care about.

steveklabnik 6y ago
Those kinds of errors are made trivial to handle with ? and anyhow. At least, once you’ve got a bit of practice with it. And it’s barely slower to write out; 1 character in most cases, and “Result<>” on your return type. I ported some random Python to Rust six months ago: https://news.ycombinator.com/item?id=22712441 https://news.ycombinator.com/item?id=22712441 Here's the version I'd write today: use anyhow::Result; use chrono::NaiveDateTime; use serde::Deserialize; use serde_json; #[derive(Deserialize)] struct Person { name: String, age: u32, hired: NaiveDateTime, emails: Vec<String>, } fn main() -> Result<()> { let data = std::fs::read_to_string("agenda.json")?; let mut people: Vec<Person> = serde_json::from_str(&data)?; people.sort_by(|a, b| b.name.cmp(&a.name)); for person in &people { println!("{} ({}) - {}", person.name, person.age, person.hired); for email in &person.emails { println!(" - {}", email); } } Ok(()) } I learned that Chrono supports serde so I can remove my own parsing, and using ? instead of unwrap, because it's not harder and it ends up being nicer overall. (EDIT: Ah actually, it won't recognize this specific format automatically, so I still would write the parsing code. Even then, it's still roughly in the same ballpark.)
winstonewert 6y ago
It's not really about the borrow checker, but the rest of the Rust type system. Even with throwaway code that can help catch some problems. Is it worth the tradeoffs? Unclear.

steveklabnik 6y ago

Those kinds of errors are made trivial to handle with ? and anyhow. At least, once you’ve got a bit of practice with it. And it’s barely slower to write out; 1 character in most cases, and “Result<>” on your return type. I ported some random Python to Rust six months ago: https://news.ycombinator.com/item?id=22712441 https://news.ycombinator.com/item?id=22712441 Here's the version I'd write today: use anyhow::Result; use chrono::NaiveDateTime; use serde::Deserialize; use serde_json; #[derive(Deserialize)] struct Person { name: String, age: u32, hired: NaiveDateTime, emails: Vec<String>, } fn main() -> Result<()> { let data = std::fs::read_to_string("agenda.json")?; let mut people: Vec<Person> = serde_json::from_str(&data)?; people.sort_by(|a, b| b.name.cmp(&a.name)); for person in &people { println!("{} ({}) - {}", person.name, person.age, person.hired); for email in &person.emails { println!(" - {}", email); } } Ok(()) } I learned that Chrono supports serde so I can remove my own parsing, and using ? instead of unwrap, because it's not harder and it ends up being nicer overall. (EDIT: Ah actually, it won't recognize this specific format automatically, so I still would write the parsing code. Even then, it's still roughly in the same ballpark.)

winstonewert 6y ago

It's not really about the borrow checker, but the rest of the Rust type system. Even with throwaway code that can help catch some problems. Is it worth the tradeoffs? Unclear.