indexed

This package contains element representations that contain the "context" of the element. That is, the elements in this package are pairs of a root element and a path (to the actual element itself). The "context" of an element also contains an optional document URI.

An example of where such a representation can be useful is XML Schema. After all, to interpret an element definition in an XML schema, we need context of the element definition to determine the target namespace, or to determine whether the element definition is top level, etc.

Below follows a simple example query, using the uniform query API:

// Note the import of package indexed, and not of its members. That is indeed a best practice!
import eu.cdevreeze.yaidom.indexed

val indexedBookstoreElem = indexed.Elem(bookstoreElem)

val scalaBookAuthors =
  for {
    bookElem <- indexedBookstoreElem \ EName("{http://bookstore/book}Book")
    if (bookElem \@ EName("ISBN")) == Some("978-0981531649")
    authorElem <- bookElem \\ EName("{http://bookstore/author}Author")
  } yield authorElem

The query for Scala book authors would have been exactly the same if normal Elems had been used instead of indexed.Elems (replacing indexedBookstoreElem by bookstoreElem)!

There is no explicit functional update support for the indexed elements in this package. Of course the underlying elements can be functionally updated (for element implementations that offer such update support), and indexed elements can be created from the update results, but this is hardly efficient functional update support.

One problem with efficient functional updates for indexed elements is that updating just one child element means that all subsequent child elements may have to be updated as well, adapting the stored paths. In comparison, simple elements do not have this restriction, and can be updated in isolation. Hence the functional update support for simple elements but not for the different indexed element implementations.