',' x scalar @array;

##</code><code>##

m/.(?{ $array[ pos ] = do_smth(); })(*FAIL)/;

##</code><code>##

#!/usr/bin/perl -wl

use strict;

my @A = ( -5, 3, 1, -2 );

my $acc = 0;

for my $i ( 0 .. @A - 2 ){
	$acc += abs( $A[ $i ] - $A[ $i + 1 ] );
	}

print $acc;

$acc = 0;

( ',' x ( @A - 1 ) ) =~ /
	.
	(?{
		$acc += abs( $A[ $-[0] ] - $A[ $-[0] + 1 ] );
		})
	(*FAIL)
	/x;

print $acc;

##</code><code>##

13
13

##</code><code>##

#!/usr/bin/perl -wl

use strict;

my @A = qw( d c b a );

print "@A";

for my $i ( 0 .. @A - 2 ){
	for my $j ( reverse $i .. @A - 2 ){
		print ' ' x $i . "<$A[ $j ]> cmp <$A[ $j + 1 ]>";
		}
	}

print "-" x 5;

( ',' x ( @A - 1 ) ) =~ m/
	.
	.*
	(?{
		print ' ' x $-[0] . "<$A[ $+[0] - 1 ]> cmp <$A[ $+[0] ]>";
		})
	(*FAIL)
	/x;

print "-" x 5;

( ',' x ( @A - 1 ) ) =~ m/
	.
	.*
	(?{
		  $A[ $+[0] - 1 ] gt $A[ $+[0] ] and
		( $A[ $+[0] - 1 ],   $A[ $+[0] ] ) =
		  reverse
		( $A[ $+[0] - 1 ],   $A[ $+[0] ] );
		print "--@A";
		})
	(*FAIL)
	/x;

print "@A";

##</code><code>##

d c b a
<b> cmp <a>
<c> cmp <b>
<d> cmp <c>
 <b> cmp <a>
 <c> cmp <b>
  <b> cmp <a>
-----
<b> cmp <a>
<c> cmp <b>
<d> cmp <c>
 <b> cmp <a>
 <c> cmp <b>
  <b> cmp <a>
-----
--d c a b
--d a c b
--a d c b
--a d b c
--a b d c
--a b c d
a b c d

##</code><code>##

#!/usr/bin/perl -wl

use strict;

my @A = qw( d c b a );

print "@A";

for my $i ( 0 .. @A - 2 ){
	for my $j ( $i .. @A - 2 ){
		print ' ' x $i . "<$A[ $j ]> cmp <$A[ $j + 1 ]>";
		}
	}

print "-" x 5;

( ',' x ( @A - 1 ) ) =~ m/
	.
	.*?
	(?{
		print ' ' x $-[0] . "<$A[ $+[0] - 1 ]> cmp <$A[ $+[0] ]>";
		})
	(*FAIL)
	/x;

print "-" x 5;

my $jmin;

( ',' x ( @A - 1 ) ) =~ m/
	.
	(?{ $jmin = $+[0] - 1; })
	.*?
	(?{
		$A[ $jmin ] gt $A[ $+[0] ] and
		$jmin = $+[0];
		})
	$
	(?{ $jmin != $-[0] and
		( $A[ $-[0] ], $A[ $jmin ] ) =
		  reverse
		( $A[ $-[0] ], $A[ $jmin ] );
		print "--@A";
		})
	(*FAIL)
	/x;

print "@A";

##</code><code>##

d c b a
<d> cmp <c>
<c> cmp <b>
<b> cmp <a>
 <c> cmp <b>
 <b> cmp <a>
  <b> cmp <a>
-----
<d> cmp <c>
<c> cmp <b>
<b> cmp <a>
 <c> cmp <b>
 <b> cmp <a>
  <b> cmp <a>
-----
--a c b d
--a b c d
--a b c d
a b c d

##</code><code>##

#!/usr/bin/perl -w

use strict;

my @A = ( 1 .. 3, 'abc', 'zz', 79, 444, 5 );

for( my $i = 0; $i < @A - 2; $i += 2 ){
	print "[$A[ $i ]-$A[ $i + 1 ]-$A[ $i + 2 ]]";
	}
print "\n";

for my $i ( grep $_ % 2 == 0, 0 .. @A - 3 ){
	print "[$A[ $i ]-$A[ $i + 1 ]-$A[ $i + 2 ]]";
	}
print "\n";

( ',' x ( @A - 1 ) ) =~ m/
	(,)
	(,)(*SKIP)
	(,)
	(?{ print "[$A[ $-[ 1 ] ]-$A[ $-[ 2 ] ]-$A[ $-[ 3 ] ]]" })
#	(?{ local $" = '-'; print "[@A[ @-[ 1 .. 3 ] ]]" })  # same output
#	(?{ local $" = '-'; print "[@A[ $-[ 0 ] .. ( pos ) - 1 ]]" })  # same output
	(*FAIL)
	/x;
print "\n";

##</code><code>##

[1-2-3][3-abc-zz][zz-79-444]
[1-2-3][3-abc-zz][zz-79-444]
[1-2-3][3-abc-zz][zz-79-444]