a easy way to treat flexible token order?

[Jibin Han]

Hi,
    The data file I am processing has some flexible token order, for
example, a complete line can be:
        firstname="something", middlename="something",
lastname="something"
    or
        firstname="something", lastname="something",
middlename="something"
    or
        lastname="something", firstname="something",
middlename="something"

    I am wondering if there is some easy way to handle this other than
my current practice by writing a rule and action for each case?

Thanks!