has is a subroutine as any other. You can call it in a loop, you can pass variables as its arguments. 
for my $attr (qw( country customer_number ticket_type )) {
    my $reader  = "get_$attr";
    my $clearer = "clear_$attr";
    has $attr => (
            is        => 'rw',
            reader    => $reader,
            writer    => "set_$attr",
            predicate => "has_$attr",
            clearer   => $clearer,
            trigger   => sub {
                my ($self)  = @_;
                if (! defined $self->$reader || $self->$reader eq '' )
+ {
                    $self->$clearer;
                }
            }
    );
}

[download]

Notice I switched the two conditions in the || to prevent warnings about undefined.

($q=q:Sq=~/;[c](.)(.)/;chr(-||-|5+lengthSq)`"S|oS2"`map{chr |+ord
}map{substrSq`S_+|`|}3E|-|`7**2-3:)=~y+S|`+$1,++print+eval$q,q,a,

[download]

In reply to Re: Autoclearing all accessors in a Mouse/Moose class by choroba
in thread Autoclearing all accessors in a Mouse/Moose class by yulivee07

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