unblessed references in lists in Perl

thelonius · 06-21-2006, 10:43 AM

Hello,

I wonder what it would be the right way to treat anonymous references in lists. I have a list like this:

Code:

$element = ['one', 'two', {'3' => 'three', '4' => 'four'}, 'five'];

and when in a loop I want to print it, I get the error "Can't call method "treat" on unblessed reference":

Code:

treat( $element);

sub treat {
  @array = @{$_[0]} if ref( $_[0]) eq "ARRAY";
  @array = values %{$_[0]} if ref( $_[0]) eq "HASH";

  for( @array) {
    if( ref( $_) eq "HASH") {
      treat $_;
    }
    else {
      print "$_ ";
    }
  }
};

I get 'one two' and the error message, and not the 'one two three four five'.

Thank you in advance.

puffinman · 06-21-2006, 12:43 PM

Is this in a package file? Is there another method somewhere also called treat? Sounds like perl thinks treat is a method call, which would only make sense to call with an instance of the object created by the package. It seems odd that it wouldn't error at your first call to treat, because the array ref is also unblessed. The only difference between the two calls is the parentheses...

thelonius · 06-21-2006, 01:09 PM

Quote:

Originally Posted by puffinman

The only difference between the two calls is the parentheses...

...and this was the error not to use parentheses for the second call. Now it works.

Here is the complete correct version (pay attention to the 'my' declaration of the inner array):

Code:

#!/usr/bin/perl
$element = ['one', 'two', {'3' => 'three', '4' => 'four'}, 'five'];
treat( $element);
sub treat {
  my @array;
  @array = @{$_[0]} if ref($_[0]) eq "ARRAY";
  @array = values %{$_[0]} if ref($_[0]) eq "HASH";
  for (@array) {
    if( ref( $_) =~ /(HASH)|(ARRAY)/) {
      treat( $_);
    }
    else {
      print "$_ ";
    }
  }
}

Thanksssssss!!!!!!!!