Re: Re: Determining the true type of a reference

I'm not sure I actually responded to the real question. I still think naming a class 'ARRAY' is begging for trouble.

But here a snippet that knows the difference:

$aref = []; $href = {}; $sref = \""; 

my $text = 'some text';
my $ref = \$text;
my $blessed = bless($ref, 'ARRAY');

print prt_typ($_) for ( [ $aref, '$aref'],  [ $href, '$href'], 
                    [ $sref, '$sref'], [$blessed, '$blessed'], );

sub prt_typ
{
    my ( $rin, $str )  = @{$_[0]};
    print "ref($str) = ", ref($rin), "\n";
    eval { my $x = ${$rin} };
    return "$str is SCALAR\n\n" unless $@;
    eval { my %x = %{$rin} };
    return "$str is HASH\n\n" unless $@;
    eval { my @x = @{$rin} };
    return "$str is ARRAY\n\n" unless $@;
}
[download]

Results in:

ref($aref) = ARRAY
$aref is ARRAY

ref($href) = HASH
$href is HASH

ref($sref) = SCALAR
$sref is SCALAR

ref($blessed) = ARRAY
$blessed is SCALAR
[download]

Bob Niederman, http://bob-n.com

Comment on Re: Re: Determining the true type of a reference Select or Download Code

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Re^3: Determining the true type of a reference by adrianh (Chancellor) on May 25, 2003 at 23:13 UTC
Unless we bring overloading in :-). Consider: `{ package FakeScalar; use overload '${}' => sub { \(shift->{scalar}) }; sub new { bless { scalar => undef }, shift }; }; use Scalar::Util qw(reftype); my $scalar = FakeScalar->new; print "reftype(FakeScalar) = ", reftype($scalar), "\n"; print prt_typ( [ $scalar => 'FakeScalar'] ); __END__ # produces reftype(FakeScalar) = HASH ref(FakeScalar) = FakeScalar FakeScalar is SCALAR` [download]	[reply] [d/l]
Re: Re^3: Determining the true type of a reference by bobn (Chaplain) on May 26, 2003 at 01:44 UTC
OK, tyou're right. Now, tell me why you would do the vile, evil thing you did. ;-P Bob Niederman, http://bob-n.com	[reply]
Re^5: Determining the true type of a reference by adrianh (Chancellor) on May 26, 2003 at 10:11 UTC
Now, tell me why you would do the vile, evil thing you did. :-) I might do it when you have an object that can usefully be treated as another perl type. For example consider an class like this: `my $account = Account->new(; $account->add_transaction(30, 'food')->add_transaction(3, 'comics') ->add_transaction(99, 'food'); # get the second transaction my $transaction = $account->[1]; # get all the food transactions my $array_ref = $account->{food};` [download] I freely admit there are other APIs that would allow you to do the same thing. You could also implement the above with tie instead of overloading. However, overloading is not a totally insane solution if you just need read access.	[reply] [d/l]