This is an extended abstract of the talk given by Michael Kay in the keynote address of the DocEng2003 symposium.
This paper proposes an extension to the XQuery language to solve the problem of positional grouping: that is, problems in which it is necessary to convert a flat sequence into a hierarchy by recognizing patterns in the sequence of items. Positional grouping is contrasted with value-based grouping, where the allocation of items to groups is based on common… (More)
This paper describes the internal features of the Saxon XQuery processor that make the most significant contribution to its speed of execution. For each of the features, an attempt is made to quantify the contribution, in most cases by comparing performance achieved when the feature is enabled or disabled.