Method to calculate array length

wannymahoots has asked for the wisdom of the Perl Monks concerning the following question:

I'm attempting to define a method that will calculate the length of an array stored within an object, but am running up against an issue. In the example given below, when I call scaler on the deferenced array (which I would hope would return the array length?), the call behaves as if I'd attempted to call a method of the class called "scaler"? Clearly I'm misunderstanding something fundamental here and would really appreciate any clarification...

{
    package Test;
    our $AUTOLOAD;

    sub new {
        my ($class) = @_;
        return bless {arr => [1,2,3,4]}, $class;
    }
    
    sub len {
        my ($self) = @_;
        scaler(@{$self->arr});
     }
    
    sub DESTROY {}
    
    sub AUTOLOAD {
        my ($self) = @_;
        (my $f = $AUTOLOAD) =~ s/.+://;
        print "function \"$f\" called\n";
        $self->{$f};
    }
}

my $tmp = Test->new;
print $tmp->len,"\n";
[download]

Output:

function "arr" called
function "scaler" called
Can't use string ("1") as a HASH ref while "strict refs" in use at ./t
+est.pl line 25.
[download]

Comment on Method to calculate array length Select or Download Code

Replies are listed 'Best First'.
Re: Method to calculate array length by toolic (Bishop) on Nov 21, 2012 at 13:40 UTC
Also, you can get more help from B::Lint `perl -MO=Lint code.pl Nonexistant subroutine 'Test::scaler' called at code.pl z syntax OK` [download] and perlcritic `perlcritic -1 code.pl Subroutine "scaler" is neither declared nor explicitly imported at lin +e 12, column 9. This might be a major bug. (Severity: 4)` [download]	[reply] [d/l] [select]
Re: Method to calculate array length (scalar is scalar) by Anonymous Monk on Nov 21, 2012 at 13:30 UTC
scalar is scalar not scaler -- singulat, not climber haha, singular	[reply]
Re^2: Method to calculate array length (scalar is scalar) by wannymahoots (Novice) on Nov 21, 2012 at 13:36 UTC
Amazing. For once, it is spelling and not coding that has let me down.	[reply]
Re^3: Method to calculate array length (scalar is scalar) by rovf (Priest) on Nov 21, 2012 at 15:23 UTC
Just a note: In this particular case, you could have found out that it was a spelling problem, since your AUTOLOAD was triggered. Of course this is not so clearly to see than having getting a "function not defined" error message. Partially for this reason, I refrain from using AUTOLOAD, unless I have very compelling reason to use it. -- Ronald Fischer <ynnor@mm.st>	[reply] [d/l]

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