Abstract: An apparatus comprises a stylesheet compiler and a document processor. The stylesheet compiler is configured to identify expressions in a stylesheet and is configured to generate one or more expression trees representing the expressions. Expressions having one or more common nodes are represented as children of a subtree that represents the common nodes. Coupled to receive a document and the expression tree, the document processor is configured to evaluate the expressions represented in the one or more expression trees against the document.

Abstract: Numerous embodiments of structured data transformation are disclosed. Some embodiments include characterizing at least a portion of an expression in a stylesheet as evaluatable at a phase wherein the phase is one of a compile phase, a parse phase, or a transformation phase of applying the stylesheet to a document to transform the document in a document transformation appliance, applying at least a portion of the expression to the document in the phase determined in the characterizing, combining results from applying the at least a portion of the expression and from applying other expressions to the document to generate a transformed document, and outputting the transformed document or saving the transformed document to memory.