Good approach! But you could simplify it a lot by noticing that your sprintf only prepends zeros: 
my @sects= qw( 1 2 2.2 2.13 2.1.7 3.4a 10.1 10.10 10.1a 1a.2 );
my %sects;
for ( @sects ) {
    ( my $key = $_ ) =~ s/(\d+)/substr("0000$1",-4)/ge;
    $sects{$key} = $_;
}
print "@sects{sort keys %sects}\n";

[download]

Parameterizing on $maxdigs is left an an excercise for the acolyte. :-) (And extra credit if you knew that you could interpolate a hash slice.)

If we simplify the problem space by eliminating the alphanumerics, things get even neater--we don't even need a hash any more: 

my @sorted = map { join '.', unpack 'N*', $_ }
             sort
             map { pack 'N*', split /\./ }
             @unsorted;

[download]

    -- Chip Salzenberg, Free-Floating Agent of Chaos

In reply to RE: Re: Sorting on Section Numbers by chip
in thread Sorting on Section Numbers by Zoogie

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