in reply to Determining whether a value is zero.

I don't suppose that you would entertain any argument with your arbitrary definition of what constitutes zero?

Any definition that deems "0" as zero, but "00", "0.0" & "0 " as not, is so arbitrary as to render the challenge pointless.

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.
  • Comment on Re: Determining whether a value is zero.

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Re^2: Determining whether a value is zero.
by Corion (Patriarch) on Mar 10, 2011 at 13:31 UTC

    It may be pointless from the sense of practical application. I found it interesting as a way of familiarizing the various representations of zero, and how the various operators treat a scalar (dual-)variable in Perl.

[reply]

      I'm not adverse to a purely intellectual challenge.

      But the specification of what is and what is not zero doesn't seem to comply with any either real-world or rational definition that I can think of. I cannot think of any existing implementation that would interprete "0" as zero, and not "00" or "0 ". Nor can I see any rational for doing so.

      Without some logic as to why these arbitrary rules have been picked, you might as well do:

      #! perl -slw
use strict;
use feature qw[ state ];
use Scalar::Util qw[ dualvar ];


my @true = ( 0, "0", 0.0, Scalar::Util::dualvar( 0, 1 ) );
my @false = (
    1, "foo", "00", "0 ", undef, "",
    Scalar::Util::dualvar( 1, 0 ), "0.0"
);

sub isZero {
    state %isZero;
    unless( %isZero ) {
        $isZero{ $_ } = 1 for @true;
        $isZero{ $_ } = 0 for @false;
    }
    return $isZero{ $_ } if exists $isZero{ $_ };
    die "Don't know";
}


print "$_ : ", isZero( $_ ) for @true;
print "$_ : ", isZero( $_ ) for @false;

      [download]

      As it can be infinitely extended to deal with any set of illogical rules.

      Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
      "Science is about questioning the status quo. Questioning authority".
      In the absence of evidence, opinion is indistinguishable from prejudice.
[reply]
[d/l]
        Without some logic as to why these arbitrary rules have been picked,
        Ok, here's the other part of the challenge: what's the logic about what for some people seem to be "arbitrary" or even "illogical"?
[reply]
Re^2: Determining whether a value is zero.
by Anonymous Monk on Mar 10, 2011 at 13:36 UTC
    There is one point, in "0.0"
[reply]
Re^2: Determining whether a value is zero.
by JavaFan (Canon) on Mar 10, 2011 at 13:42 UTC
    Any definition that deems "0" as zero, but "00", "0.0" & "0 " as not, is so arbitrary
    Please, take that up with Larry Wall. It isn't my fault that he considered "0" to be false, but "00", "0.0" & "0 " to be true. But then, that guy is well known for his arbitrary decisions which he never entertains any argument with, rendering the entire Perl language pointless.
[reply]
      he considered "0" to be false,

      That's not quite the same things as considering '00' to be non-zero is it! 

      C:\test>perl -e"print '00' == 0"
1

      [download]
      Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
      "Science is about questioning the status quo. Questioning authority".
      In the absence of evidence, opinion is indistinguishable from prejudice.
[reply]
[d/l]
        That's not quite the same things as considering '00' to be non-zero is it!
        No, but you were complaining about the arbitraryness. It has the same arbitraryness as for true/false. 
        C:\test>perl -e"print '00' == 0"
1

        [download]
        So what? 
        $ perl -E 'say "BrowserUK" == 0'
1
$ perl -E 'say "00" eq 0'

$

        [download]
        Heh, I made the challenge, I make the rules. If you don't like the rules, don't play.
[reply]
[d/l]
[select]
      Certainly is interesting that quoted 00 is true while quoted 0 is false (but it sounds like '0', "0" are special cases). 
      perl -E 'say 0      ? q{true} : q{false}'  # false
perl -E 'say 00     ? q{true} : q{false}'  # false
perl -E 'say q{0}   ? q{true} : q{false}'  # false
perl -E 'say qq{0}  ? q{true} : q{false}'  # false
perl -E 'say q{00}  ? q{true} : q{false}'  # true
perl -E 'say qq{00} ? q{true} : q{false}'  # true

      [download]
      Perl 5.10.1 on Solaris 10 SPARC.

      Elda Taluta; Sarks Sark; Ark Arks
[reply]
[d/l]

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