in reply to isa() on any scalar

You can use Scalar::Util::blessed to test the reference 
use Scalar::Util qw (blessed);

if (blessed($value) and $value->isa('Node')) {
   #
}

[download]
-- gam3
A picture is worth a thousand words, but takes 200K.

Replies are listed 'Best First'.
Re^2: isa() on any scalar
by rvosa (Curate) on Jun 11, 2005 at 20:41 UTC
    Two things: i) are you building an OO module for phylogenetics? (If yes, let's join forces); ii) here's how I did it: 
    sub parent {
    my $self = $_[0];
    if ( $_[1] ) {
        my $parent = $_[1];
        if ( $parent->can('parent') ) {
            $self->[PARENT] = $parent;
        }
        else {
            my $ref = ref $self;
            carp "parents can only be $ref objects";
            return;
        }
    }
    return $self->[PARENT];
}

    [download]
    This follows the "if it walks like a duck" paradigm. Not saying that this is the best way to do it, but it works for me.
[reply]
[d/l]

      Phylogeny: (n.)
      1. The evolutionary development and history of a species or higher taxonomic grouping of organisms. Also called phylogenesis.
      2. The evolutionary development of an organ or other part of an organism: the phylogeny of the amphibian intestinal tract.
      3. The historical development of a tribe or racial group.

      Okay, just looked it up... nope, that's not what I'm doing at all. Sorry! Thanks for the piece of code though!

          -Bryan

[reply]
Re^2: isa() on any scalar
by mrborisguy (Hermit) on Jun 13, 2005 at 03:18 UTC

    After looking around, trying to figure out what I want to do, I decided to use the 'walk like a duck' approach and use can. However, the same problem occured! So I use this solution together with can. Thanks for this one!

    use Scalar::Util qw(blessed);

if ( blessed( $value ) and $value->can( 'parent' ) ) {
   #
}

    [download]

        -Bryan

[reply]
[d/l]

In Section Seekers of Perl Wisdom