- sxml:id id-indexprocedure
Returns a procedure that accepts a nodeset and returns a nodeset containing the elements in the id-index that match the string-values of each entry of the nodeset. XPath Rec. 4.1
The id-index is an alist with unique IDs as key, and elements as values:
id-index = ( (id-value . element) (id-value . element) ... )