does anyone have a more _concise_ (read: no temporary) way of doing this? 
while (($key, $lref) = each %HoL)
{
    my %h = ();
    @h{@{$lref}} = (1) x @{$lref};
    $HoL{$key} = \%h;
}

In reply to hash of lists - hash of hashes by visnu

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