Hacker News Reader

Comment by breadwinner | Hacker News Reader

> acceptable practice outside of Java.

What is the acceptable practice outside of Java?

Do you prefer to check for errors after every function call? That's what you had in C language, and the problem is that the logic gets buried inside all the error checking, and that makes code hard to read (and write).

View on HN

The general answer is "represent it in the type system". That's typically via discriminated unions like Rust's Result, or something which emulates it (such as OneOf or Dunet for C#, although it will be a native part of the language soon).

Pattern matching, nullable types, and the Try* method conventions are also ways of representing the potential for failure explicitly.

Checked exceptions are represented in the type system. There is fundamentally no difference between these two:

    A b() throws C
    fn b() -> Result<A, C>

    A a = try {
        b()
    } catch (C c) {
        new A()
    }

    val a = b() match {
        Ok(a) => a
        Failure(c) => A()
    }

Reply on news.ycombinator.com