Heres a not very tight implementation, but it should make clear whats going on:
{
my %hash = (
'Ask' => 1,
'Bob' => 1,
'Cat' => 1,
'amy' => 1,
'ben' => 1,
'can' => 1,
);
print join "\n", sort case_sorter keys %hash;
}
sub case_sorter {
my $first_a = substr $a, 0, 1;
my $first_b = substr $b, 0, 1;
if ( ($first_a eq uc($first_a)) && ($first_b eq uc($first_b)) ) {
return $a cmp $b;
}
elsif ( $first_a eq uc($first_a) ) {
return 1;
}
elsif ( $first_b eq uc($first_b) ) {
return -1;
}
else {
return $a cmp $b;
}
}