Re: Call by Result

Newsgroups	comp.lang.java.programmer
From	Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at>
Subject	Re: Call by Result
References	(3 earlier) <G8nIp.1578$SG4.1543@newsfe03.iad> <slrniv461g.phi.avl@gamma.logic.tuwien.ac.at> <8CtIp.4644$PA5.4578@newsfe01.iad> <slrniv9qag.phi.avl@gamma.logic.tuwien.ac.at> <4df5290c$0$49183$e4fe514c@news.xs4all.nl>
Message-ID	<slrnivefbp.phi.avl@gamma.logic.tuwien.ac.at> (permalink)
Date	2011-06-14 10:52 +0000

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Silvio <silvio@moc.com> wrote:
> Well, here is an example in Scala:
>  [...]
> def getString(s : String) : Option[String] =
> {
>     if (s.reverse == s) Some(s.toLowerCase)
>     else None
> }
>  [...]
>  val t = getString(s)
>  [...]
> t match
> {
>     case Some(r) => println("Success, return value is: " + r)
>     case None => println("Failure")
> }

Ah, thanks.  Yep, I've seen this concept once when playing with 
OCaml (which mentions Haskell as one of its roots). Never got 
warm with it, though.

In the end, it isn't all that more concise than C++/Java...
It's a bit like C's unions with some byte ahead to tell which
of the variants is the current one, and bunch of logical operations
that is often trivially converted into a couple of (possibly nested)
"if-else"s.   I'm not saying it's bad, just it didn't impress me all
that much, so far.

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Call by Result Gene Wirchenko <genew@ocis.net> - 2011-06-09 23:03 -0700
  Re: Call by Result Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-06-10 07:33 +0000
    Re: Call by Result Nigel Wade <nmw-news@ion.le.ac.uk> - 2011-06-10 10:03 +0100
      Re: Call by Result Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-06-10 09:47 +0000
      Re: Call by Result Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-06-10 08:23 -0300
        Re: Call by Result Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-06-10 13:12 +0000
          Re: Call by Result Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-06-10 15:44 -0300
            Re: Call by Result Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-06-12 16:29 +0000
              Re: Call by Result Silvio <silvio@moc.com> - 2011-06-12 23:00 +0200
                Re: Call by Result Silvio <silvio@moc.com> - 2011-06-12 23:06 +0200
                Re: Call by Result Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-06-14 10:52 +0000
                Re: Call by Result Silvio <silvio@moc.com> - 2011-06-14 17:13 +0200
                Re: Call by Result Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-06-14 17:58 -0300
                Re: Call by Result Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-06-14 21:18 +0000
                Re: Call by Result Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-06-14 20:14 -0300
                Re: Call by Result Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-06-15 07:13 -0300
                Re: Call by Result Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-06-15 12:50 +0000
                Re: Call by Result Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-06-15 18:52 -0300
                Re: Call by Result lewbloch <lewbloch@gmail.com> - 2011-06-15 07:06 -0700
                Re: Call by Result Michael Wojcik <mwojcik@newsguy.com> - 2011-06-15 21:33 -0400
                Re: Call by Result Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-06-16 11:03 +0000
                Re: Call by Result "H.J. Sander Bruggink" <sander.bruggink@uni-due.de> - 2011-06-16 13:09 +0200
                Re: Call by Result Lewis Bloch <lewisbloch@google.com> - 2011-06-16 06:59 -0700
                Re: Call by Result "John B. Matthews" <nospam@nospam.invalid> - 2011-06-16 23:14 -0400
        Re: Call by Result Gene Wirchenko <genew@ocis.net> - 2011-06-10 11:31 -0700
          Re: Call by Result Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-06-12 14:27 -0300
      Re: Call by Result Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2011-06-10 07:20 -0700
      Re: Call by Result Patricia Shanahan <pats@acm.org> - 2011-06-10 09:30 -0700
        Re: Call by Result Gene Wirchenko <genew@ocis.net> - 2011-06-10 11:44 -0700
    Re: Call by Result Gene Wirchenko <genew@ocis.net> - 2011-06-10 11:26 -0700
      Re: Call by Result Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-06-11 15:07 +0000
        Re: Call by Result Abu Yahya <abu_yahya@invalid.com> - 2011-06-11 23:00 +0530
          Re: Call by Result Martin Gregorie <martin@address-in-sig.invalid> - 2011-06-11 19:36 +0000
            Re: Call by Result Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-06-11 21:06 +0000
              Re: Call by Result Martin Gregorie <martin@address-in-sig.invalid> - 2011-06-12 10:53 +0000
                Re: Call by Result Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2011-06-12 09:28 -0700
                Re: Call by Result Martin Gregorie <martin@address-in-sig.invalid> - 2011-06-12 17:48 +0000
                Re: Call by Result Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2011-06-12 13:19 -0700
            Re: Call by Result Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2011-06-11 15:39 -0700
              Re: Call by Result Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-06-12 11:07 +0000
                Re: Call by Result markspace <-@.> - 2011-06-12 07:02 -0700
                Re: Call by Result Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2011-06-12 09:39 -0700
                Re: Call by Result Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-06-14 10:29 +0000
                Re: Call by Result Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2011-06-14 09:14 -0700
                Re: Call by Result markspace <-@.> - 2011-06-14 09:21 -0700
                Re: Call by Result Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2011-06-14 09:53 -0700
                Re: Call by Result Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2011-06-14 09:57 -0700
            Re: Call by Result Gene Wirchenko <genew@ocis.net> - 2011-06-12 21:44 -0700
        Re: Call by Result Gene Wirchenko <genew@ocis.net> - 2011-06-12 21:40 -0700
  Re: Call by Result Patricia Shanahan <pats@acm.org> - 2011-06-10 01:30 -0700
    Re: Call by Result Gene Wirchenko <genew@ocis.net> - 2011-06-10 11:45 -0700
  Re: Call by Result Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-06-10 07:50 -0400
  Re: Call by Result Silvio <silvio@moc.com> - 2011-06-10 15:35 +0200
  Re: Call by Result Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-06-10 13:56 +0000
  Re: Call by Result Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2011-06-10 07:22 -0700
    Re: Call by Result Gene Wirchenko <genew@ocis.net> - 2011-06-10 11:56 -0700
    Re: Call by Result Gene Wirchenko <genew@ocis.net> - 2011-06-10 11:57 -0700
      Re: Call by Result Patricia Shanahan <pats@acm.org> - 2011-06-10 13:50 -0700
        Re: Call by Result Gene Wirchenko <genew@ocis.net> - 2011-06-12 21:53 -0700
          Re: Call by Result Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-06-13 07:20 -0300
            Re: Call by Result Gene Wirchenko <genew@ocis.net> - 2011-06-13 08:08 -0700
      Re: Call by Result Wojtek <nowhere@a.com> - 2011-06-11 16:35 -0700
        Re: Call by Result Martin Gregorie <martin@address-in-sig.invalid> - 2011-06-12 11:05 +0000
        Re: Call by Result Gene Wirchenko <genew@ocis.net> - 2011-06-12 21:56 -0700
          Re: Call by Result Wojtek <nowhere@a.com> - 2011-06-14 00:40 -0700
    Re: Call by Result Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-06-11 21:18 +0000
  Re: Call by Result markspace <-@.> - 2011-06-10 08:43 -0700
  Re: Call by Result RedGrittyBrick <RedGrittyBrick@spamweary.invalid> - 2011-06-10 17:01 +0100
    Re: Call by Result Martin Gregorie <martin@address-in-sig.invalid> - 2011-06-10 16:55 +0000
    Re: Call by Result Gene Wirchenko <genew@ocis.net> - 2011-06-10 11:59 -0700
      Re: Call by Result Wojtek <nowhere@a.com> - 2011-06-11 16:24 -0700
        Re: Call by Result Gene Wirchenko <genew@ocis.net> - 2011-06-12 21:59 -0700
          Re: Call by Result Paul Cager <paul.cager@googlemail.com> - 2011-06-13 07:53 -0700
          Re: Call by Result Wojtek <nowhere@a.com> - 2011-06-14 00:43 -0700
  Re: Call by Result Gene Wirchenko <genew@ocis.net> - 2011-06-10 11:55 -0700
  Re: Call by Result Steven Simpson <ss@domain.invalid> - 2011-06-11 09:09 +0100
  Re: Call by Result Cholo Lennon <chololennon@hotmail.com> - 2011-06-16 11:30 -0300
    Re: Call by Result Paul Cager <paul.cager@googlemail.com> - 2011-06-17 02:38 -0700
      Re: Call by Result Gene Wirchenko <genew@ocis.net> - 2011-06-17 12:06 -0700
    Re: Call by Result lewbloch <lewbloch@gmail.com> - 2011-06-17 06:40 -0700
      Re: Call by Result Cholo Lennon <chololennon@hotmail.com> - 2011-06-17 11:43 -0300

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