I love building a startup in Rust but wouldn't pick it again • Hacker News Board

Re: I love building a startup in Rust but wouldn't pick it again

#11

Post by jakelazaroff » Fri, Feb 17, 2023, 3:49 PM UTC

PaulHoule wrote: post #2

I can't get it why people would prefer to add "?" to everything instead of just having exceptions which automate that behavior. In the bad old days of C there were two kinds of programs: programs without correct error handling, and programs where half the loc are unhappy paths that do what exceptions do... with a huge amount of work. Today people are repeating the same mistakes of the past, putting a "?" on everythin…

Exceptions come with their own weirdness. Usually, if you want to handle an exception, you need to wrap the code that could generate it in a block, which means any variables declared there won't be available in the parent scope. I'd much rather have the ability to just write normal code and deal with the error on the spot, along with some syntactic sugar (such as "?") to return that error to the caller.

Re: I love building a startup in Rust but wouldn't pick it again

#12

Post by jb1991 » Fri, Feb 17, 2023, 3:49 PM UTC

nemothekid wrote: post #5

PaulHoule wrote: post #2

I can't get it why people would prefer to add "?" to everything instead of just having exceptions which automate that behavior. In the bad old days of C there were two kinds of programs: programs without correct error handling, and programs where half the loc are unhappy paths that do what exceptions do... with a huge amount of work. Today people are repeating the same mistakes of the past, putting a "?" on everythin…

I prefer having extra work done writing code (adding "?") than having to do extra work reading code. Exceptions are functionally invisible control flow; it isn't clear to the reader that a function may blow up if the exceptions are unhandled.

In Swift, at least, the possibility that a function can throw must be marked as part of its signature, and the exception cannot be ignored if it is thrown so the call requires explicit syntax as well, so there is no way to miss that something could "blow up" when reading the code.

Re: I love building a startup in Rust but wouldn't pick it again

#13

Post by dom96 » Fri, Feb 17, 2023, 3:49 PM UTC

I have the same impression of Rust: great for software that is well scoped/defined and needs to be stable and efficient, not so much for quick iterations (which for startups is important) and software that doesn't need top performance.

I think in general that the Rust hype has outgrown what it's good for. If you're writing a web app in Rust then you may want to ask yourself if you're making the right choice.

Re: I love building a startup in Rust but wouldn't pick it again

#14

Post by Jensson » Fri, Feb 17, 2023, 3:50 PM UTC

nemothekid wrote: post #5

PaulHoule wrote: post #2

I can't get it why people would prefer to add "?" to everything instead of just having exceptions which automate that behavior. In the bad old days of C there were two kinds of programs: programs without correct error handling, and programs where half the loc are unhappy paths that do what exceptions do... with a huge amount of work. Today people are repeating the same mistakes of the past, putting a "?" on everythin…

I prefer having extra work done writing code (adding "?") than having to do extra work reading code. Exceptions are functionally invisible control flow; it isn't clear to the reader that a function may blow up if the exceptions are unhandled.

In Java functions declares Exceptions in its type signature, so it does all of that automatically. Then you get a compile error if you don't handle it in the function, or you need to declare the function throws it, so it is type safe.

Note that people now consider that as a mistake, people prefer having Exceptions be hidden instead of explicit and requiring handling like that.

Re: I love building a startup in Rust but wouldn't pick it again

#15

Post by [deleted] » Fri, Feb 17, 2023, 3:50 PM UTC

PaulHoule wrote: post #2

I can't get it why people would prefer to add "?" to everything instead of just having exceptions which automate that behavior. In the bad old days of C there were two kinds of programs: programs without correct error handling, and programs where half the loc are unhappy paths that do what exceptions do... with a huge amount of work. Today people are repeating the same mistakes of the past, putting a "?" on everythin…

[deleted]

Re: I love building a startup in Rust but wouldn't pick it again

#16

Post by larusso » Fri, Feb 17, 2023, 3:50 PM UTC

PaulHoule wrote: post #2

I can't get it why people would prefer to add "?" to everything instead of just having exceptions which automate that behavior. In the bad old days of C there were two kinds of programs: programs without correct error handling, and programs where half the loc are unhappy paths that do what exceptions do... with a huge amount of work. Today people are repeating the same mistakes of the past, putting a "?" on everythin…

How would an exception automate the behavior of „?“?

What ? does in rust is to unwrap the result check if it is err and return from the function with an error result. On top of that it will auto-convert the error type (if the type has the from/into traits implemented)

So it would do:

try { //the code that may fail } catch (error) { //do we just throw the same error? //or convert the exception to a custom other exception }

If I see an API that throws me an low level exception without context I go mad. Like an file not found exception etc when executing an API that does multiple file IO operations.

Re: I love building a startup in Rust but wouldn't pick it again

#17

Post by jb1991 » Fri, Feb 17, 2023, 3:51 PM UTC

Jensson wrote: post #14

nemothekid wrote: post #5

Earlier quoted context omitted.

I prefer having extra work done writing code (adding "?") than having to do extra work reading code. Exceptions are functionally invisible control flow; it isn't clear to the reader that a function may blow up if the exceptions are unhandled.

In Java functions declares Exceptions in its type signature, so it does all of that automatically. Then you get a compile error if you don't handle it in the function, or you need to declare the function throws it, so it is type safe. Note that people now consider that as a mistake, people prefer having Exceptions be hidden instead of explicit and requiring handling like that.

> Note that people now consider that as a mistake, people prefer having Exceptions be hidden instead of explicit and requiring handling like that.

Well, Swift is a much newer language than Java, and exceptions in Swift cannot be hidden either. And some people do rather like this.

Re: I love building a startup in Rust but wouldn't pick it again

#18

Post by pclmulqdq » Fri, Feb 17, 2023, 3:51 PM UTC

PaulHoule wrote: post #2

I can't get it why people would prefer to add "?" to everything instead of just having exceptions which automate that behavior. In the bad old days of C there were two kinds of programs: programs without correct error handling, and programs where half the loc are unhappy paths that do what exceptions do... with a huge amount of work. Today people are repeating the same mistakes of the past, putting a "?" on everythin…

There's some subtlety here:

1. Exceptions have very high performance costs (equivalent to a longjmp which is very slow), so if you expect to have exceptional cases, it's probably a lot more efficient to not use exceptions.

2. Exceptions break the linear flow of the code when you read it, so now you have to read a lot more code to figure out what the exception paths are and where and how they are handled.

Re: I love building a startup in Rust but wouldn't pick it again

#19

Post by taeric » Fri, Feb 17, 2023, 3:52 PM UTC

nemothekid wrote: post #5

PaulHoule wrote: post #2

I can't get it why people would prefer to add "?" to everything instead of just having exceptions which automate that behavior. In the bad old days of C there were two kinds of programs: programs without correct error handling, and programs where half the loc are unhappy paths that do what exceptions do... with a huge amount of work. Today people are repeating the same mistakes of the past, putting a "?" on everythin…

I prefer having extra work done writing code (adding "?") than having to do extra work reading code. Exceptions are functionally invisible control flow; it isn't clear to the reader that a function may blow up if the exceptions are unhandled.

I get where you are coming from, but imagine if every other "to the human" process description we had was done this way.

I actually think this would be a fun one. How to make scrambled eggs, but where all failure cases are covered. Would be the "Hal fixes a lightbulb" in prose.

Re: I love building a startup in Rust but wouldn't pick it again

#20

Post by chomp » Fri, Feb 17, 2023, 3:52 PM UTC

PaulHoule wrote: post #2

I can't get it why people would prefer to add "?" to everything instead of just having exceptions which automate that behavior. In the bad old days of C there were two kinds of programs: programs without correct error handling, and programs where half the loc are unhappy paths that do what exceptions do... with a huge amount of work. Today people are repeating the same mistakes of the past, putting a "?" on everythin…

It's mostly philosophical, are you fine with blowing up with an exception, or would you rather have your functions return known values for the unhappy path? I personally like exceptions in exceptional cases, but much rather having functions with explicit contracts (e.g. "this will return either True or False in all input cases", not "this will return either True, or Exception in all cases when $foo doesn't exist in the database, and woe unto the programmer that forgets to catch this.")