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

Groups > comp.lang.java.programmer > #19302

Re: Assigning void

Show key headers only | View raw

Jeff Higgins <jeff@invalid.invalid> wrote:

(snip on use of expressions as statements)

>> 6.5.15 of the C Rationale only states
>> the construct is allowed and not why.
>> 15.25 of the Java Spec. only states
>> the construct is disallowed and not why.
>> Does it sound childish to ask why?

> Don't get me wrong. I understand that in both
> languages this construct is the conditional "operator".
> I'm asking only why it cannot also be shorthand for
> an if-then-else statement.
> boolean expression ? block : block

C allows any expression as a statement, no matter how useless.

It is most often used in C to ignore the return value of a 
function, not that it is always a good idea. Way too many 
programs ignore the return value of fclose() which may be
the only indication that writing to a file failed.

Java special cases the method call, but otherwise doesn't allow
expressions that don't do assignment as statements.
(Read the JLS for more specific details.)

There are other Java restrictions that seem to be there
to encourage better coding. For one, Java requires that the
compiler be able to verify that a scalar variable is 
assigned a value before it is used. Most other languages
trust the programmer to get it right, with no guarantees
if it is wrong.

Now, it would have been easier for Java to always initialize
scalar variables to zero/false/null, but that doesn't encourage
good coding practices.

There is always a compromise between generality and readability.

I don't know how many of the Java originators are still around
to ask. If you really want to know, though, that is the way.

-- glen

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

Thread

Assigning void Wojtek <nowhere@a.com> - 2012-10-12 22:54 -0700
  Re: Assigning void Lew <lewbloch@gmail.com> - 2012-10-12 23:27 -0700
    Re: Assigning void Wojtek <nowhere@a.com> - 2012-10-13 12:35 -0700
  Re: Assigning void Eric Sosman <esosman@comcast-dot-net.invalid> - 2012-10-13 09:26 -0400
  Re: Assigning void Donkey Hottie <donkey@fredriksson.dy.fi> - 2012-10-13 17:06 +0300
    Re: Assigning void Jeff Higgins <jeff@invalid.invalid> - 2012-10-13 10:34 -0400
    Re: Assigning void Wanja Gayk <brixomatic@yahoo.com> - 2012-10-13 22:33 +0200
      Re: Assigning void Jeff Higgins <jeff@invalid.invalid> - 2012-10-13 17:34 -0400
      Re: Assigning void Eric Sosman <esosman@comcast-dot-net.invalid> - 2012-10-13 17:45 -0400
        Re: Assigning void Eric Sosman <esosman@comcast-dot-net.invalid> - 2012-10-13 21:35 -0400
        Re: Assigning void Wanja Gayk <brixomatic@yahoo.com> - 2012-10-16 00:16 +0200
  Re: Assigning void Jeff Higgins <jeff@invalid.invalid> - 2012-10-13 11:59 -0400
    Re: Assigning void glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-10-13 17:05 +0000
      Re: Assigning void Jeff Higgins <jeff@invalid.invalid> - 2012-10-13 14:26 -0400
        Re: Assigning void markspace <-@.> - 2012-10-13 11:51 -0700
          Re: Assigning void Jeff Higgins <jeff@invalid.invalid> - 2012-10-13 15:08 -0400
          Re: Assigning void Wojtek <nowhere@a.com> - 2012-10-13 12:28 -0700
            Re: Assigning void markspace <-@.> - 2012-10-13 12:42 -0700
              Re: Assigning void Lew <lewbloch@gmail.com> - 2012-10-13 12:54 -0700
                OT - Trolling Wojtek <nowhere@a.com> - 2012-10-13 14:16 -0700
                Re: OT - Trolling Jeff Higgins <jeff@invalid.invalid> - 2012-10-13 18:09 -0400
                Re: OT - Trolling Gene Wirchenko <genew@ocis.net> - 2012-10-14 18:47 -0700
              Re: Assigning void Martin Gregorie <martin@address-in-sig.invalid> - 2012-10-13 20:28 +0000
              Re: Assigning void Wojtek <nowhere@a.com> - 2012-10-13 13:31 -0700
                Re: Assigning void Joerg Meier <joergmmeier@arcor.de> - 2012-10-20 18:00 +0200
                Re: Assigning void Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2012-10-20 09:56 -0700
                Re: Assigning void "Peter J. Holzer" <hjp-usenet2@hjp.at> - 2012-10-21 13:24 +0200
                Re: Assigning void Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2012-10-21 10:23 -0700
                Re: Assigning void "Peter J. Holzer" <hjp-usenet2@hjp.at> - 2012-10-22 00:13 +0200
                Re: Assigning void Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2012-10-21 16:25 -0700
                Re: Assigning void "Peter J. Holzer" <hjp-usenet2@hjp.at> - 2012-10-22 08:43 +0200
                Re: Assigning void "Peter J. Holzer" <hjp-usenet2@hjp.at> - 2012-10-22 10:18 +0200
                Re: Assigning void Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2012-10-22 08:14 -0700
                Re: Assigning void glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-10-21 19:45 +0000
                Re: Assigning void "Peter J. Holzer" <hjp-usenet2@hjp.at> - 2012-10-22 00:14 +0200
            Re: Assigning void Lew <lewbloch@gmail.com> - 2012-10-13 12:44 -0700
              Re: Assigning void Jukka Lahtinen <jtfjdehf@hotmail.com.invalid> - 2012-10-15 14:38 +0300
                Re: Assigning void Lew <lewbloch@gmail.com> - 2012-10-15 09:11 -0700
        Re: Assigning void Jeff Higgins <jeff@invalid.invalid> - 2012-10-13 15:03 -0400
          Re: Assigning void glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-10-13 20:21 +0000
    Re: Assigning void Lew <lewbloch@gmail.com> - 2012-10-13 12:38 -0700
      Re: Assigning void markspace <-@.> - 2012-10-13 12:49 -0700
        Re: Assigning void Lew <lewbloch@gmail.com> - 2012-10-13 13:03 -0700
          Re: Assigning void Robert Klemme <shortcutter@googlemail.com> - 2012-10-14 14:09 +0200
            Re: Assigning void Lew <lewbloch@gmail.com> - 2012-10-14 11:31 -0700
      Re: Assigning void Jeff Higgins <jeff@invalid.invalid> - 2012-10-13 19:55 -0400
        Re: Assigning void Jeff Higgins <jeff@invalid.invalid> - 2012-10-13 20:25 -0400
          Re: Assigning void Jeff Higgins <jeff@invalid.invalid> - 2012-10-13 21:01 -0400
            Re: Assigning void Gene Wirchenko <genew@ocis.net> - 2012-10-14 18:42 -0700
  Re: Assigning void Roedy Green <see_website@mindprod.com.invalid> - 2012-10-14 00:51 -0700
  Re: Assigning void Jeff Higgins <jeff@invalid.invalid> - 2012-10-14 10:40 -0400
  Re: Assigning void Sven Köhler <remove-sven.koehler@gmail.com> - 2012-10-21 01:24 +0200
    Re: Assigning void Wojtek <nowhere@a.com> - 2012-10-21 14:52 -0700
      Re: Assigning void Eric Sosman <esosman@comcast-dot-net.invalid> - 2012-10-21 20:13 -0400
        Re: Assigning void Wojtek <nowhere@a.com> - 2012-10-21 20:20 -0700
          Re: Assigning void Sven Köhler <remove-sven.koehler@gmail.com> - 2012-10-22 11:12 +0200
        Re: Assigning void Wanja Gayk <brixomatic@yahoo.com> - 2012-10-24 22:03 +0200
          Re: Assigning void Eric Sosman <esosman@comcast-dot-net.invalid> - 2012-10-24 17:47 -0400
            Re: Assigning void Wanja Gayk <brixomatic@yahoo.com> - 2012-10-25 01:02 +0200
              Re: Assigning void Eric Sosman <esosman@comcast-dot-net.invalid> - 2012-10-24 20:21 -0400
                Re: Assigning void Martin Gregorie <martin@address-in-sig.invalid> - 2012-10-25 20:04 +0000
                (OT) Re: Assigning void Eric Sosman <esosman@comcast-dot-net.invalid> - 2012-10-25 16:31 -0400
                Re: (OT) Re: Assigning void Martin Gregorie <martin@address-in-sig.invalid> - 2012-10-25 20:44 +0000
            Re: Assigning void Arved Sandstrom <asandstrom2@eastlink.ca> - 2012-10-25 07:25 -0300
              Re: Assigning void Lew <lewbloch@gmail.com> - 2012-10-25 11:12 -0700
      Re: Assigning void Sven Köhler <remove-sven.koehler@gmail.com> - 2012-10-22 11:01 +0200
      Re: Assigning void Daniele Futtorovic <da.futt.news@laposte-dot-net.invalid> - 2012-10-23 00:38 +0200

csiph-web