1. A method implemented at least in part by a computer, the method comprising: obtaining a copy of a source XML document; obtaining a transformation document that includes declarative statements that indicate modifications to make to the copy to transform the copy into a target XML document, the transformation document also including location information that indicates nodes in the copy upon which the modifications are to operate; transforming the copy of the source XML document according to the transformation document to create the target XML document; and providing the target XML document.