BEGIN {
    if (IS_PRODUCTION) {
        eval <<'SUB';
        sub Readonly (\[$@%]@) {
            given (ref $_[0]) {
                when ('SCALAR') {${$_[0]} = $_[1]}
                when ('ARRAY') {@{$_[0]} = @_[1 .. $#_]} 
                when ('HASH') {%{$_[0]} = @_[1 .. $#_]}  
            }
        }
SUB
    }
    else {
        require Readonly;
        Readonly->import;  
    }
}