Hacker News Reader

Comment by stickfigure | Hacker News Reader

Interesting but the "Isn't this just multiple return?" section seems to completely miss the point. I don't see any examples of what multiple-return would look like. And multiple-return is what I want.

At first glance, it looks like this (sure, more powerful) pattern matching system is not going to satisfy my desire for a compact syntax that lets me do the equivalent of this typescript:

    const [foo, bar] = getMeTwoThings();

View on HN

No, there is no tuple support yet in Java. That would require something like variadic generics or a special compile time syntax sugar for tuples as the sole use of variadic generics.

With the pattern matching the best you are going to get is nasty boiler plate like

    var returnedTuple = getMeTwoThings();
    if (returnedTuple instanceof MyTupleType(Foo foo, Bar bar)) {
        // Do something with foo and bar
    } else {
        // Not reachable unless refactoring, etc. So panic here.
    }

That else clause is so terrible you'd probably just rather use the getters from the type.

I think there is ongoing discussion to support

      var MyTupleType(Foo foo, Bar bar) = getMeTwoThings();

which IIRC may be even simplified to

      var MyTupleType(foo, bar) = getMeTwoThings();

EDIT: found it https://mail.openjdk.java.net/pipermail/amber-spec-experts/2...

     let Point(var x, var y) = aPoint

I might not be aware of best practices.

What are the benefits of having a multiple return type function?

I just assume that one can use an object if this is needed throughout the whole code..

Or maybe create an arraylist if possible and return that?

Using the object(/class) as you say is the probably "the Java way" to do this, given their historical "everything is an object" stance (which has been eroded a bit, though, with some of the functional support). But it sure is nice to do a multi-returns, here and there, without having to create another class. A class which required you to write boilerplate (getters/setters). Maybe records are some sort of compromise. Probably a non-compromise for people who like the multi-returns.

Reply on news.ycombinator.com