Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.java.programmer > #37465

Re: underscore as keyword in Java 9

Show all headers | View raw

On Saturday, September 23, 2017 at 12:47:10 PM UTC-4, j4n bur53 wrote:
> As long as Java doesn't have multi-returns, there
> will be not many use cases. For multi returns, if
> they were in the Java language, it could be offered
> as in the Go Programming Language:
> 
> /* fetching the y coordinate of a 3D point */
> _, y, _ := coord(p)
> https://stackoverflow.com/questions/27764421/what-is-in-a-golang-declaration
> 
> Which reminds me of the Prolog language so called
> annonymous variables:
> 
>    ?- .., coord(P,_,Y,_).
> 
> Andreas Leitgeb schrieb:
> > When googling for underscore keyword I found a
> > mail by Brian Goetz, where he hinted for a future
> > use of the "_" keyword:
> >
> >   http://mail.openjdk.java.net/pipermail/lambda-dev/2013-July/010670.html

I don't see the point to _ as a placeholder for a value passed in or out of a method in an OO language.

Passing in if we don't want to pass a parameter we either have an overload for the method to default that parameter or pass in a dummy value such as null for an object or -1 for primitive number.

Passing out if you don't need that parameter don't reference it.  To pass out more than one we can use a native array[], a List object, a built in multi-value object ie java.awt.Point, or a custom object.

I'm sure I've never used _ by itself, so if it doesn't affect _variable or _method we should be fine.  I normally write catch (Exception e) even if I never reference the e variable within the block.

Back to comp.lang.java.programmer | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

underscore as keyword in Java 9 Andreas Leitgeb <avl@logic.at> - 2017-09-23 11:58 +0000
  Re: underscore as keyword in Java 9 j4n bur53 <janburse@fastmail.fm> - 2017-09-23 18:46 +0200
    Re: underscore as keyword in Java 9 Arne Vajhøj <arne@vajhoej.dk> - 2017-09-23 21:01 -0400
      Re: underscore as keyword in Java 9 Andreas Leitgeb <avl@logic.at> - 2017-09-24 11:25 +0000
        Re: underscore as keyword in Java 9 j4n bur53 <janburse@fastmail.fm> - 2017-09-24 17:30 +0200
        Re: underscore as keyword in Java 9 Arne Vajhøj <arne@vajhoej.dk> - 2017-09-24 18:24 -0400
          Re: underscore as keyword in Java 9 Andreas Leitgeb <avl@logic.at> - 2017-09-24 23:27 +0000
            Re: underscore as keyword in Java 9 Arne Vajhøj <arne@vajhoej.dk> - 2017-09-24 21:10 -0400
              Re: underscore as keyword in Java 9 Andreas Leitgeb <avl@logic.at> - 2017-09-25 13:30 +0000
    Re: underscore as keyword in Java 9 Eric Douglas <e.d.programmer@gmail.com> - 2017-09-25 08:07 -0700
      Re: underscore as keyword in Java 9 lewbloch@gmail.com - 2017-09-25 13:21 -0700
      Re: underscore as keyword in Java 9 Silvio <silvio@internet.com> - 2017-09-25 23:30 +0200
        Re: underscore as keyword in Java 9 Arne Vajhøj <arne@vajhoej.dk> - 2017-09-25 20:24 -0400
          Re: underscore as keyword in Java 9 j4n bur53 <janburse@fastmail.fm> - 2017-09-26 13:37 +0200
          Re: underscore as keyword in Java 9 Silvio <silvio@internet.com> - 2017-09-27 19:05 +0200
            Re: underscore as keyword in Java 9 Eric Douglas <e.d.programmer@gmail.com> - 2017-09-27 10:25 -0700
              Re: underscore as keyword in Java 9 Silvio <silvio@internet.com> - 2017-09-27 23:02 +0200
            Re: underscore as keyword in Java 9 Arne Vajhøj <arne@vajhoej.dk> - 2017-09-27 20:02 -0400
              Re: underscore as keyword in Java 9 Eric Douglas <e.d.programmer@gmail.com> - 2017-09-28 05:11 -0700
                Re: underscore as keyword in Java 9 Arne Vajhøj <arne@vajhoej.dk> - 2017-09-28 20:42 -0400
          Re: underscore as keyword in Java 9 Sebastian <nowhere@nirvana.org> - 2017-09-27 20:26 +0200
            Re: underscore as keyword in Java 9 Silvio <silvio@internet.com> - 2017-09-27 23:10 +0200
        Re: underscore as keyword in Java 9 Andreas Leitgeb <avl@logic.at> - 2017-09-26 08:29 +0000
          Re: underscore as keyword in Java 9 Silvio <silvio@internet.com> - 2017-09-27 19:08 +0200
          Re: underscore as keyword in Java 9 Sebastian <nowhere@nirvana.org> - 2017-09-27 21:46 +0200
  Re: underscore as keyword in Java 9 Eric Douglas <e.d.programmer@gmail.com> - 2017-09-27 06:53 -0700
    Re: underscore as keyword in Java 9 Andreas Leitgeb <avl@logic.at> - 2017-09-27 15:59 +0000
      Re: underscore as keyword in Java 9 Arne Vajhøj <arne@vajhoej.dk> - 2017-09-27 19:18 -0400
        Re: underscore as keyword in Java 9 Daniele Futtorovic <da.futt.news@laposte.net> - 2017-09-28 11:41 +0200

csiph-web