# [ pOnseq(2) >          =    9, 25, 16
#{ _ _ , _ _ , _ _ } @2  = [   ,   ,    ]
#  1\    1\    0\
#    4     4   0
#  4     8     4
#          8     8
#        4     4
#

##</code><code>##

#!perl
use strict;
use warnings;
use feature qw/state say/;

use Devel::Peek;

my @array = ( "0", "0\n", 0, '0', '0'."\n" );

foreach my $zeroe( @array ){
 state $za;
 say "\$zeroe $zeroe\__________";
# @$za = Dump $zeroe;  
 state $fh_err;
 local *MYSTDERR = *STDERR;

 open STDERR, '>', 'tmp.err' or die $!; # dies to Term

  Dump $zeroe;
  Dump defined $zeroe;
  Dump length $zeroe;
  Dump 0+$zeroe;
  
 close STDERR;
 *STDERR = *MYSTDERR;
 what_is_it();
 
 say "[][][][][][][][][][]\n";

}

unlink 'tmp.err';

sub what_is_it{
 #  my $output = shift;
 #  while(defined( my $next = shift @$output )){
 #   state $c;
 #   print ++$c,": $next";
 state $fh_err;
 open $fh_err, '<', 'tmp.err' or die $!; # ....
 while( defined ( my $nextline = <$fh_err> ) ){
#  state $c;
#  print $c+=1," $nextline";
  print $nextline;  
 };
 close $fh_err;

 unlink{ 'tmp.err' };

}

##</code><code>##

$zeroe 0__________
SV = PV(0xeb850c) at 0xeba53c
  REFCNT = 2
  FLAGS = (POK,pPOK)
  PV = 0x26c4bec "0"\0
  CUR = 1
  LEN = 12
SV = PVNV(0xeb945c) at 0xeb72c0
  REFCNT = 2147483644
  FLAGS = (IOK,NOK,POK,READONLY,pIOK,pNOK,pPOK)
  IV = 1
  NV = 1
  PV = 0xeb2d74 "1"\0
  CUR = 1
  LEN = 12
SV = IV(0x26c37f8) at 0x26c37fc
  REFCNT = 1
  FLAGS = (PADTMP,IOK,pIOK)
  IV = 1
SV = IV(0x26c37e8) at 0x26c37ec
  REFCNT = 1
  FLAGS = (PADTMP,IOK,pIOK)
  IV = 0
[][][][][][][][][][]

$zeroe 0
__________
SV = PV(0xeb851c) at 0xeba5cc
  REFCNT = 2
  FLAGS = (POK,pPOK)
  PV = 0x26c4ccc "0\n"\0
  CUR = 2
  LEN = 12
SV = PVNV(0xeb945c) at 0xeb72c0
  REFCNT = 2147483644
  FLAGS = (IOK,NOK,POK,READONLY,pIOK,pNOK,pPOK)
  IV = 1
  NV = 1
  PV = 0xeb2d74 "1"\0
  CUR = 1
  LEN = 12
SV = IV(0x26c37f8) at 0x26c37fc
  REFCNT = 1
  FLAGS = (PADTMP,IOK,pIOK)
  IV = 2
SV = IV(0x26c37e8) at 0x26c37ec
  REFCNT = 1
  FLAGS = (PADTMP,IOK,pIOK)
  IV = 0
[][][][][][][][][][]

$zeroe 0__________
SV = PVIV(0x2663380) at 0xeba61c
  REFCNT = 2
  FLAGS = (IOK,POK,pIOK,pPOK)
  IV = 0
  PV = 0x26c4e4c "0"\0
  CUR = 1
  LEN = 12
SV = PVNV(0xeb945c) at 0xeb72c0
  REFCNT = 2147483644
  FLAGS = (IOK,NOK,POK,READONLY,pIOK,pNOK,pPOK)
  IV = 1
  NV = 1
  PV = 0xeb2d74 "1"\0
  CUR = 1
  LEN = 12
SV = IV(0x26c37f8) at 0x26c37fc
  REFCNT = 1
  FLAGS = (PADTMP,IOK,pIOK)
  IV = 1
SV = IV(0x26c37e8) at 0x26c37ec
  REFCNT = 1
  FLAGS = (PADTMP,IOK,pIOK)
  IV = 0
[][][][][][][][][][]

$zeroe 0__________
SV = PV(0xeb8534) at 0xeba64c
  REFCNT = 2
  FLAGS = (POK,pPOK)
  PV = 0x26c4d8c "0"\0
  CUR = 1
  LEN = 12
SV = PVNV(0xeb945c) at 0xeb72c0
  REFCNT = 2147483644
  FLAGS = (IOK,NOK,POK,READONLY,pIOK,pNOK,pPOK)
  IV = 1
  NV = 1
  PV = 0xeb2d74 "1"\0
  CUR = 1
  LEN = 12
SV = IV(0x26c37f8) at 0x26c37fc
  REFCNT = 1
  FLAGS = (PADTMP,IOK,pIOK)
  IV = 1
SV = IV(0x26c37e8) at 0x26c37ec
  REFCNT = 1
  FLAGS = (PADTMP,IOK,pIOK)
  IV = 0
[][][][][][][][][][]

$zeroe 0
__________
SV = PV(0xeb854c) at 0xeba66c
  REFCNT = 2
  FLAGS = (POK,pPOK)
  PV = 0x26c4e2c "0\n"\0
  CUR = 2
  LEN = 12
SV = PVNV(0xeb945c) at 0xeb72c0
  REFCNT = 2147483644
  FLAGS = (IOK,NOK,POK,READONLY,pIOK,pNOK,pPOK)
  IV = 1
  NV = 1
  PV = 0xeb2d74 "1"\0
  CUR = 1
  LEN = 12
SV = IV(0x26c37f8) at 0x26c37fc
  REFCNT = 1
  FLAGS = (PADTMP,IOK,pIOK)
  IV = 2
SV = IV(0x26c37e8) at 0x26c37ec
  REFCNT = 1
  FLAGS = (PADTMP,IOK,pIOK)
  IV = 0
[][][][][][][][][][]

Press any key to continue . . .

##</code><code>##

||      |||     |||||   ||||||| ||||||||||||||| |||||||||||||||||||||||||||||||||||||||||||

testing prim nat: ||
split_pat: (?^u:(\|\|))
splitted: 1 x || h remainder:
prim nat was ||
prim nat now


testing prim nat: |||
split_pat: (?^u:(\|\|))
splitted: 1 x || h remainder: |
prim nat was |||
prim nat now |


testing prim nat: |||||
split_pat: (?^u:(\|\|))
splitted: 2 x || h remainder: |
prim nat was |||||
prim nat now |


testing prim nat: |||||||
split_pat: (?^u:(\|\|))
splitted: 3 x || h remainder: |
prim nat was |||||||
prim nat now |


testing prim nat: |||||||||||||||
split_pat: (?^u:(\|\|))
splitted: 7 x || h remainder: |
prim nat was |||||||||||||||
prim nat now |


testing prim nat: |||||||||||||||||||||||||||||||||||||||||||
split_pat: (?^u:(\|\|))
splitted: 21 x || h remainder: |
prim nat was |||||||||||||||||||||||||||||||||||||||||||
prim nat now |

||      2       my todo hex()   1 x ||  remainder:
|||     3       my todo hex()   1 x ||  remainder: |
|||||   5       my todo hex()   2 x ||  remainder: |
||||||| 7       my todo hex()   3 x ||  remainder: |
||||||||||||||| f       my todo hex()   7 x ||  remainder: |
|||||||||||||||||||||||||||||||||||||||||||     2b      my todo hex()   21 x || remainder: |

Press any key to continue . . .

##</code><code>##

cpanm (App::cpanminus) 1.7044 on perl 5.014002 built for MSWin32-x86-multi-thread
Work directory is C:\Users\ZOMBIKE~1/.cpanm/work/1562478735.5744
You have make C:\Dwimperl\c\bin\dmake.exe
You have LWP 6.03
Falling back to Archive::Tar 1.80
Searching Module::Compile () on cpanmetadb ...
--> Working on Module::Compile
Fetching http://www.cpan.org/authors/id/I/IN/INGY/Module-Compile-0.37.tar.gz
-> OK
Unpacking Module-Compile-0.37.tar.gz
Entering Module-Compile-0.37
Checking configure dependencies from META.json
Checking if you have ExtUtils::MakeMaker 6.58 ... Yes (7.36)
Configuring Module-Compile-0.37
Running Makefile.PL
Checking if your kit is complete...
Looks good
Generating a dmake-style Makefile
Writing Makefile for Module::Compile
Writing MYMETA.yml and MYMETA.json
-> OK
Checking dependencies from MYMETA.json ...
Checking if you have Capture::Tiny 0 ... Yes (0.15)
Checking if you have Digest::SHA1 2.13 ... Yes (2.13)
Checking if you have ExtUtils::MakeMaker 0 ... Yes (7.36)
Checking if you have App::Prove 0 ... Yes (3.23)
Building and testing Module-Compile-0.37
cp lib/Module/Optimize.pod blib\lib\Module\Optimize.pod
cp lib/Module/Compile/Opt.pm blib\lib\Module\Compile\Opt.pm
cp lib/Module/Compile.pm blib\lib\Module\Compile.pm
cp lib/Module/Optimize.pm blib\lib\Module\Optimize.pm
cp lib/Module/Compile/Opt.pod blib\lib\Module\Compile\Opt.pod
cp lib/Module/Compile.pod blib\lib\Module\Compile.pod
C:\"Dwimperl\perl\bin\perl.exe" "-MExtUtils::Command::MM" "-MTest::Harness" "-e" "undef *Test::Harness::Switches; test_harness(0, 'blib\lib', 'blib\arch')" t/*.t
t/author-pod-syntax.t .. skipped: these tests are for testing by the author
t/compile.t ............ ok

#   Failed test '.pmc load works same'
#   at t/data1.t line 29.
#          got: '1'
#     expected: '0'
# Output was: t/data2.t.subrun .. 
# No subtests run 
# 
# Test Summary Report
# -------------------
# t/data2.t.subrun (Wstat: 0 Tests: 0 Failed: 0)
#   Parse errors: No plan found in TAP output
# Files=1, Tests=0,  1 wallclock secs ( 0.06 usr +  0.05 sys =  0.11 CPU)
# Result: FAIL
# Error was: 
# Looks like you failed 1 test of 4.
t/data1.t .............. 
Dubious, test returned 1 (wstat 256, 0x100)
Failed 1/4 subtests 
t/fold_blocks.t ........ ok
t/lexical.t ............ ok
t/orz.t ................ ok
t/parse.t .............. ok
t/pm.t ................. skipped: In progress...
t/pmc.t ................ ok

Test Summary Report
-------------------
t/data1.t            (Wstat: 256 Tests: 4 Failed: 1)
  Failed test:  4
  Non-zero exit status: 1
Files=9, Tests=23,  2 wallclock secs ( 0.06 usr +  0.05 sys =  0.11 CPU)
Result: FAIL
Failed 1/9 test programs. 1/23 subtests failed.
dmake.exe:  Error code 255, while making 'test_dynamic'
-> FAIL You don't seem to have a PAGER :/
Entering C:/Users/ZOMBIKE~1/.cpanm/work/1562478735.5744/Module-Compile-0.37 with C:\WINDOWS\system32\cmd.exe

##</code><code>##

  DB<2> s
Capture::Tiny::capture((eval 40)[C:/Dwimperl/perl/site/lib/Capture/Tiny.pm:38]:1):
1:      sub capture(&;@) {unshift @_, 1, 1, 0, 0; goto \&_capture_tee;}
                                                                                                                          DB<2>

...

File::Spec::Win32::tmpdir(C:/Dwimperl/perl/lib/File/Spec/Win32.pm:73):

File::Temp::tempfile(C:/Dwimperl/perl/lib/File/Temp.pm:1381):
1381:     croak "Error in tempfile() using $template: $errstr"
1382:       unless (($fh, $path) = _gettemp($template,
1383:                                       "open" => $options{'OPEN'},
1384:                                       "mkdir"=> 0 ,
1385:                                       "unlink_on_close" => $unlink_on_close,
1386:                                       "suffixlen" => length($options{'SUFFIX'}),
1387:                                       "ErrStr" => \$errstr,
1388:                                       "use_exlock" => $options{EXLOCK},
1389:                                      ) );


  DB<15> s
File::Temp::_gettemp(C:/Dwimperl/perl/lib/File/Temp.pm:360):
360:      if (scalar(@_) % 2 != 0) {

...

  DB<15>
File::Temp::_replace_XX(C:/Dwimperl/perl/lib/File/Temp.pm:627):
627:      my $end = ( $] >= 5.006 ? "\\z" : "\\Z" );
                                                                                                                          DB<15> s
File::Temp::_replace_XX(C:/Dwimperl/perl/lib/File/Temp.pm:629):
629:      if ($ignore) {
                                                                                                                          DB<15> x $end
0  '\\z'
                                                                                                                          DB<16>
...


File::Temp::_replace_XX(C:/Dwimperl/perl/lib/File/Temp.pm:632):
632:        $path =~ s/X(?=X*$end)/$CHARS[ int( rand( @CHARS ) ) ]/ge;
                                                                                                                          DB<16> x $path
0  '\\XXXXXXXXXX'

...

  DB<18>
File::Temp::_replace_XX(C:/Dwimperl/perl/lib/File/Temp.pm:634):
634:      return $path;
                                                                                                                          DB<18> x $path
0  '\\ApibgN64sj'

...

  DB<20> s
File::Spec::Win32::splitpath(C:/Dwimperl/perl/lib/File/Spec/Win32.pm:210):
210:        my ($volume,$directory,$file) = ('','','');
                                                                                                                          DB<20> x @_
0  'File::Spec'
1  '\\ApibgN64sj'

...

  DB<29>
File::Temp::_gettemp(C:/Dwimperl/perl/lib/File/Temp.pm:513):
513:            $open_success = sysopen($fh, $path, $flags, 0600);
                                                                                                                          DB<29> x $fh,$path,$flags
0  undef
1  '\\ApibgN64sj'
2  34178
                                                                                                                          DB<30> s
File::Temp::_gettemp(C:/Dwimperl/perl/lib/File/Temp.pm:515):
515:          if ( $open_success ) {
                                                                                                                          DB<30> x $open_success
0  undef
                                                                                                                          DB<31>


##</code><code>##

#!/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 $woset = weighting_oset();
 
 --$Numset->[0][0];
 print_oset($Numset);   

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

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

 }

 print_oset($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_oset( $Numset, 1 );

return( $Numset );

}

sub weighting_oset{

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

}


sub print_oset{

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

}

##### From OP #######
sub Check_ABN {
	my $number = shift ;
	my $abn_invalid = 0 ;
	my $sum = 0 ;
	$number =~ s/\ //g ;
	unless (length($number) eq 11) {
		$abn_invalid = 1 ;
		return $abn_invalid ;
	}
	
	$sum += (substr($number,0,1)-1)*10 ;
	$sum += substr($number,1,1)*1 ;
	$sum += substr($number,2,1)*3 ;
	$sum += substr($number,3,1)*5 ;
	$sum += substr($number,4,1)*7 ;
	$sum += substr($number,5,1)*9 ;
	$sum += substr($number,6,1)*11 ;
	$sum += substr($number,7,1)*13 ;
	$sum += substr($number,8,1)*15 ;
	$sum += substr($number,9,1)*17 ;
	$sum += substr($number,10,1)*19 ;
	if ($sum % 89 eq 0) {
		return $abn_invalid ;
	} else {
#		$abn_error = 1 ;
		return $abn_invalid ;
	}
	# see https://abr.business.gov.au/Help/AbnFormat
}

##</code><code>##

# example of pass by reference

##</code><code>##

# bless $var;

##</code><code>##

$arrvar->[0]; # deref array element access
$arrvar->{'anoint'}; # deref hash element access 
$arrvar->subroutine; # deref subroutine call

##</code><code>##

$arrvar->subroutine; # deref subroutine call

##</code><code>##

sub iexpectanarraycontainingdataaboutaccuracy{

 my $arrayref = shift;

## todo:  not ideal example
## also align 0/9 with degugging levels
 print {STDOUT} $arrayref->[0]," is quite accurate\n"

 print {STDOUT} $arrayref->[9]," is deeply inaccurate\n"

 return 1;

}

##</code><code>##

#!perl

use 5.10.1;
use strict;
use warnings;

use Carp;

my @array_var = qw/Double, double toil and trouble;/;

say join "\n","\nfirst:", @array_var;

add_an_item( \ @array_var, $_ ) 
   foreach qw/1234 abyzABYZ 4the5scottish6play 1when 2shall 3we 4three!/;

say join "\n","\nsecond: ",@array_var;

my $array_ref = \ @array_var;

bless $array_ref;

$array_ref->add_an_item( $_ ) 
   foreach qw/1234 Fire burn, and cauldron bubble./;

say join "\n","\nthird: ", @array_var, "\nfourth: ", @$array_ref;

sub add_an_item{
 say "\nsub args: ", join ' ', @_;

 my $avref = shift;
 my $item_to_add = shift;
                                 # <STDIN>  # use input module or this
 $item_to_add =~ tr/a-zA-Z//cd;

 $item_to_add || carp( "Skipping item.\nItems added to this array should contain letters." ) && return;   
 
 $avref->[ @$avref ] = $item_to_add;

}

exit (0);

##</code><code>##

unless(eval{ $arrayref->can(maxstr) }){
  carp $@
}else{ 
  $arrayref->maxstr()
}
# carps

##</code><code>##

#!perl

use 5.10.1;
use strict;
use warnings;
use Carp;

use parent qw'List::Util'; 

...

unless( $arrayref->can('maxstr') ){
  carp $@
}else{ 
  $arrayref->maxstr()
}

exit; #(?) :D

##</code><code>##

windos% perl -Mv5.20 -Mstrict -MConfig -w -e "say $Config{versiononly}" 

##</code><code>##

#!perl 

use 5.20;
use strict;
use warnings;
use Config qw/config_sh/;

open my $fh, '>', '.\configlist.txt' or die $!;
print {$fh} config_sh(); 
close $fh;

##</code><code>##

sub donotrun_this_is_an_example{
  
 use constant Soan = (1/12);
 my $bitmask = ~ -256**($n/8);

return Soan & $bitmask;
}

##</code><code>##

perl -pi.bak -e "

use features qw/state/;
state $nameshash = { 'Poole' => 1 };

s/(<.*?CIT-)(\w+)(-\w\d+.*?>)/"$1$2".$nameshash->{$2}++."$3"/ge;
              
" bibliofile

##</code><code>##

my %combinations = ( 
          co1 => [
                  [ qw(one two three four five) ],
                  [ qw(one one two three five) ]
                 ], 
          co2 => [
                  [ qw(one two three five seven) ],
                  [ qw(one one two three five) ]
                 ],
          co3 => [
                  [ qw(one two three five seven) ],
                  [ qw(one two three four five) ]
                 ],
          co4 => [
                  [ qw(one two three five seven) ],
                  [ qw(one two three four five) ],
                  [ qw(one one two three five) ]
                 ],
          );

reorg($_,\%combinations) 
  foreach(keys %combinations);

sub reorg{
  my($k,$h) = @_;
  foreach my $combiset(@{$h->{$k}}){
    my @uniquesets = 
       grep $_ =~ /\Aus/ keys %combinations;
    my $num = scalar(@us);
    
    foreach my $set ( @$combiset ){ 
       
      $combinations{'us'.++$num } = $set
      unless grep @$set  {<~~>} @$_,
              @combinations{@us}; 

    # where {<~~>} is 'these arrays match'
      # or the front N indices do or ...
    }

}

##</code><code>##

%combinations = ( 
          co1 => [
                  [ qw(one two three four five) ],
                  [ qw(one one two three five) ]
                 ], 
          co2 => [
                  [ qw(one two three five seven) ],
                  [ qw(one one two three five) ]
                 ],
          co3 => [
                  [ qw(one two three five seven) ],
                  [ qw(one two three four five) ]
                 ],
          co4 => [
                  [ qw(one two three five seven) ],
                  [ qw(one two three four five) ],
                  [ qw(one one two three five) ]
                 ],
          us1 => [ qw(one two three four five) ],
          us2 => [ qw(one two three five seven) ],
          us3 => [ qw(one one two three five) ],
          );