Streamed processing of input documents
The streaming code has been improved so that it is much less inclined to make copies of subtrees where these are not
needed, even when an
<xsl:copy-of> instruction is used. For example,
as a child of an element constructor instruction is now implemented as
<xsl:sequence> (by sending incoming
SAX parser events straight to the output destination). This can greatly reduce memory requirements, especially for
When parsing of the source document finishes early because no further input is required, a
is now notified to the
warning() method of the registered
ErrorListener. This can usually be ignored;
but it is sometimes useful to know that the source file has not been read to completion (which means, for example, that it has
not been completely validated).
Streaming stylesheet functions are now implemented.
The concept of streaming extensions has been dropped. Saxon now aims to conform to the XSLT 3.0 streamability rules with no restrictions and no extensions. However, Saxon still checks streamability after optimization has been performed, which may sometimes result in non-streamable code being rewritten in a way that is streamable, for example when non-streamable constructs are completely optimized away.
The (partial) implementation of "crawling" streamability in instructions such as
has therefore been dropped. In accordance with the XSLT 3.0 specification, Saxon now requires the select expression of such instructions
to be striding: that is, the select expression can use the child axis but not the descendant axis.