reverse_string.pl

use warnings;
use strict;

$_ = 'abcdefghi';

# s/./ substr $_, -$+[0], 1 /eg;    # duh, substr and array
# s#.# /(.).{$-[0]}$/; $1 #eg;      # duh, array

my $x = 0; s#.# /(.).{$x}$/; $x++; $1 #eg;

print "$_\n";





my @a = split //, shift;
print "INPUT  = <@a>";

# @a[0..$#a] = @a[map -1-$_, 0..$#a];

@a[$_,~$_] = @a[~$_,$_] for 0..$#a/2;

print "OUTPUT = <@a>";