25. A method comprising: presenting a graphical rendering of a hierarchically structured electronic document; receiving selection of a part of the graphical rendering, the selected part corresponding to a node on a hierarchical schema for the hierarchically structured electronic document, the hierarchical schema comprising a plurality of nodes; generating a structured-document path-language addressing syntax for the node; automatically simplifying the structured-document path-language addressing syntax by abbreviating the structured-document path-language address by removing one or more unique name spaces; presenting the simplified structured-document path-language syntax; and building a structured-document path-language expression comprising the structured-document path-language addressing syntax and a syntax for a structured-document path-language function, the building being effective to enable the structured-document path-language expression to treat a blank value of the selected node as a zero.
25. A method comprising: presenting a graphical rendering of a hierarchically structured electronic document; receiving selection of a part of the graphical rendering, the selected part corresponding to a node on a hierarchical schema for the hierarchically structured electronic document, the hierarchical schema comprising a plurality of nodes; generating a structured-document path-language addressing syntax for the node; automatically simplifying the structured-document path-language addressing syntax by abbreviating the structured-document path-language address by removing one or more unique name spaces; presenting the simplified structured-document path-language syntax; and building a structured-document path-language expression comprising the structured-document path-language addressing syntax and a syntax for a structured-document path-language function, the building being effective to enable the structured-document path-language expression to treat a blank value of the selected node as a zero. 29. The method of claim 25 , further comprising: receiving syntax for a structured-document path-language function; and building a structured-document path-language expression comprising the structured-document path-language addressing syntax and the syntax for the structured-document path-language function.