I designed the named parameters to start with a '-' in our current project---biggest mistake I could make.

sub foo {
  my ($self, $params) = __params({
    -a => '...',
  }, \@_);
  ...
  if ($params->{a}) {
[download]

You see the mistake above? Happend all the time, until I was forced to add this to __params():

  foreach my $key (keys %$result) {
    my $tkey = $key; $tkey =~ s/^-//;
    $result->{$tkey} = $result->{$key};
  }
  return $result;
}
[download]