in reply to Using an object's value instead of a global variable

In OO terms your exported sub the_mascot() ('-' isn't valid in a perl indenntifier :), is a class method.

However, you want this class method to return instance data. And that is a non-sequitous requirement.

Unless this is a singleton class, which is a fancy term for global, in which case you could store the handle ($self) to the one instance into $data and then use $data->{ANIMAL} in the here-doc and you would achieve what you want.

Then you would have to arrange to update $data with the object handle of the lastest incarnation of the singleton everytime new was called.

That's not to say it is the correct way, or the best way to do it, but it would work.

The problem is, if there can be more than one instance of your class, which value of ??->{ANIMAL}, ie. from which instance, should your exported function use?

Examine what is said, not who speaks.
Silence betokens consent.
Love the truth but pardon error.

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Re^2: Using an object's value instead of a global variable
by jacques (Priest) on Jan 23, 2005 at 01:19 UTC
    Unless this is a singleton class, which is a fancy term for global, in which case you could store the handle ($self) to the one instance into $data and then use $data->{ANIMAL} in the here-doc and you would achieve what you want.

    Okay, you've got me interested but I'm a bit lost. Could you kindly show me how?

[reply]

      I do not think that this is a good idea but:

      The module (with a stupid name for my purposes): 

      package _424188;
require Exporter;

our @ISA = qw[ Exporter ];
our @EXPORT = qw[ the_mascot ];

my $data = { ANIMAL => "camel" };

sub the_mascot {
    print<<"END";
Hey, did you know that Perl\'s mascot is a:

$data->{ANIMAL}

END

}

sub new {
    my $class = shift;
    return bless $data, $class;
}

sub animal {
    my $self = shift;
    $self->{ANIMAL} = $_[0];
}

sub mascot {
         the_mascot();
}

1;

      [download]

      And a program that uses it: 

      #! perl -slw
use strict;
use _424188;

the_mascot();

my $obj = new _424188;
$obj->mascot;
$obj->animal( 'dromadary' );
$obj->mascot;
the_mascot();

__END__
P:\test>424188
Hey, did you know that Perl's mascot is a:

camel


Hey, did you know that Perl's mascot is a:

camel


Hey, did you know that Perl's mascot is a:

dromadary


Hey, did you know that Perl's mascot is a:

dromadary

      [download]
      Examine what is said, not who speaks.
      Silence betokens consent.
      Love the truth but pardon error.
[reply]
[d/l]
[select]
        Nice. I never thought of it in that way... thanks
[reply]

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