#  Both should work
#
<start_html>
<perl handler param="Alice">
<pre>
Hello: ${name}
<? Dumper($_[1]) ?>
</pre>
</perl>

<perl handler="handler1" param="%{ name => Alice }">
<pre>
Hello: ${name}
<? Dumper($_[1]) ?>
</pre>
</perl>
__PERL__
use Data::Dumper;
sub handler {
    my ($self, $param)=@_;
    return $self->render( name=>$param);
}

sub handler1 {
    my ($self, $param_hr)=@_;
    return $self->render($param_hr);
}
