Hello bgroper

I thought it might be useful to construct a separate weighting array, and then apply that as part of the algorithm to the submitted ABN to check. It's a little rough but I am interested to see what the thoughts are.

#!/usr/bin/perl

use v5.20;
use strict;
use warnings;

my $Num = Prepare_Num( q'51 824 753 556' );

my $verified = check_calc($Num);

if( $verified == 1){
 say "Valid ABN"
}else{
 say "ABN check has been unsuccessful"
}

sub check_calc{

 my $Numset = shift;
 my $w_oset = weighting_oset();
 
 --$Numset->[0][0]; # -[[0],[1]] ?
 print_list($Numset);   

 my $sum;
 for my $index( 0 .. 10 ){

 $sum += $Numset->[$index][0] *= $w_oset->[$index][0]; 

 }

 print_list($Numset);

 $sum %89 == 0;
 
}

sub Prepare_Num{

my $NumString = shift;
say "arg Num: $NumString";

$NumString =~ s/[^0-9]//g;
say "s Num: $NumString";

my $count = $NumString =~ tr/0-9/0-9/;
say "count: $count";
$count == 11 or die "non-conforming ABN. Please check.";

say "tr Num: $NumString";

my $Numset = [];
while( $NumString =~ m/([0-9])/g ){
  push @$Numset, [$1]; 
}

print_list( $Numset, 1 );

return( $Numset );

}

sub weighting_oset{

 #my $woset = [[[0],[1]],[10]];
 my $w_oset = [[10]];
 push @$w_oset, map { $_ %2 == 1 ? [$_] : () } ( 1..19 );
 print_oset( $w_oset );
 return $w_oset;

}


sub print_list{

 my $Numlist = shift;
 say "list: ",@$Numlist if @_; # $_[0] == 1;
 say "list: \[", map("[@$_],", @$Numlist), "\]";

}

sub print_oset{

 my $Oset = shift;
 say "oset: ",@$Oset if @_; # $_[0] == 1;
 say "oset: \{", map("[@$_],", @$Oset), "\}";

}
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