in reply to Query about barewords

From Comma Operator:

The => operator is a synonym for the comma except that it causes a word on its left to be interpreted as a string if it begins with a letter or underscore and is composed only of letters, digits and underscores.

Hope that helps,

Athanasius <°(((>< contra mundum

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Re^2: Query about barewords
by johngg (Canon) on Sep 06, 2012 at 15:23 UTC

    Empirically, the documentation seems to be a little inaccurate as the fat comma also seems to work if the word on the left starts with a number and consists only of numbers.

    $ perl -Mstrict -Mwarnings -MData::Dumper -E '
> my %hash = (
>    1  => q{one},
>    11 => q{eleven}
>    );
> print Data::Dumper->Dumpxs( [ \ %hash ], [ qw{ *hash } ] );'
%hash = (
          '11' => 'eleven',
          '1' => 'one'
        );
$
$ perl -Mstrict -Mwarnings -MData::Dumper -E '
> my %hash = (
>    1  => q{one},
>    11 => q{eleven},
>    2t => q{fruity},
>    );
> print Data::Dumper->Dumpxs( [ \ %hash ], [ qw{ *hash } ] );'
syntax error at -e line 5, near "2t"
Execution of -e aborted due to compilation errors.
$
$ perl -Mstrict -Mwarnings -MData::Dumper -E '
> my %hash = (
>    1   => q{one},
>    11  => q{eleven},
>    _2t => q{fruity},
>    );
> print Data::Dumper->Dumpxs( [ \ %hash ], [ qw{ *hash } ] );'
%hash = (
          '11' => 'eleven',
          '1' => 'one',
          '_2t' => 'fruity'
        );
$

    [download]

    I hope this is of interest.

    Cheers,

    JohnGG

[reply]
[d/l]
      ...if the word on the left starts with a number and consists only of numbers.
      As long as you don't want to keep any leading zeros.
[reply]
        As long as you don't want to keep any leading zeros.

        The claim is less accurate than even that: 

         % say "010 => 11"
8
11

        [download]

        Also: 

          % say "123456789012345678901234567890 => 30"
1.23456789012346e+029
30
  % say "'123456789012345678901234567890' => 30"
123456789012345678901234567890
30

        [download]

        But I've also long considered the failure of "use strict; Foo::Bar =>" to likely just be an oversight. I suspect a patch to Perl's tokenizer/parser to allow '::' in so-called barewords would not be terribly difficult and might even be accepted by p5p.

        - tye        

[reply]
[d/l]
[select]
Re^2: Query about barewords
by runrig (Abbot) on Sep 06, 2012 at 15:57 UTC
    The "bareword" may also start with a "-".
[reply]

      It seems to treat as an octal number, converts to decimal and then stringifies by the look of it.

      $ perl -Mstrict -Mwarnings -MData::Dumper -E '
> my %hash = (
>    011 => q{nine},
>    11  => q{eleven},
>    _2t => q{fruity},
>    );
> print Data::Dumper->Dumpxs( [ \ %hash ], [ qw{ *hash } ] );'
%hash = (
          '11' => 'eleven',
          '_2t' => 'fruity',
          '9' => 'nine'
        );
$
$ perl -Mstrict -Mwarnings -MData::Dumper -E '
> my %hash = (
>    08  => q{eight},
>    11  => q{eleven},
>    _2t => q{fruity},
>    );
> print Data::Dumper->Dumpxs( [ \ %hash ], [ qw{ *hash } ] );'
Illegal octal digit '8' at -e line 3, at end of line
Execution of -e aborted due to compilation errors.
$

      [download]

      A zero on its own is fine.

      Update: I'm an idiot, I meant to post as a reply to this :-(

      Cheers,

      JohnGG

[reply]
[d/l]

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