%BAZ = ( FOO, 1, BAR, 1 );
%BAZ = ( (FOO) => 1, (BAR) => 1 );
%BAZ = ( FOO() => 1, BAR() => 1 );

##</code><code>##

%BAZ = map { $_ => 1 } FOO, BAR;

##</code><code>##

sub is_baz {
    my $i = shift; 
    return ( exists $BAZ{$i} ) ? 1 : 0;
}

##</code><code>##

sub is_baz {
    my $i = shift; 
    return $BAZ{$i};
}