use Data::Dumper;
use Hash::Merge qw(merge);

### 1 ###
'1a2b3c' =~ /(?:(?<digit>\d)(?<letter>[a-z]))+/;
print Dumper(\%-);

### 2 ###
my %match;
while ('1a2b3c' =~ /\G(?<digit>\d)(?<letter>[a-z])/gc) {
	%match = %{ merge(\%match, \%-) };
}
print Dumper(\%match);

##</code><code>##

$VAR1 = {
          'digit' => [
                       '3'
                     ],
          'letter' => [
                        'c'
                      ]
        };
$VAR1 = {
          'digit' => [
                       '1',
                       '2',
                       '3'
                     ],
          'letter' => [
                        'a',
                        'b',
                        'c'
                      ]
        };