17. The method of claim 15 , wherein the conditional choose function sets a condition in which existence of the first page is equated with the condition being true and in which non-existence of the first page is equated with the condition being false.
15. A method of generating a document for printing, the method comprising: generating the document template, by: defining a variable-data printing template, the template comprising a layout of document pages with at least one set of the document pages comprising a flow that contains content which is variable in response to input data, the flow spanning across the at least one set of document pages; defining a plurality of document versions, wherein in at least some of the different document versions, at least one document page across which the flow spans is absent from the at least one set of document pages, and defining the respective document versions further includes indicating the desired variable content of the flow; and generating one of the respective document versions for printing by providing input selection data to the template via variable data merging at the time of printing to automatically select one of the respective document versions, while automatically maintaining continuity of the flow when a respective one of the at least some document versions is automatically selected in which at least one document page is absent via: in the event that all pages of the at least one set exists in the input data, applying a first page sequence definition that maps the flow to span across all pages of the at least one set; and in the event that an intermediate page of the at least one set is non-existent in the input data, applying a second page sequence definition that remaps the flow to begin with a first page, include all pages of the at least one set prior to the intermediate page, and include all pages of the at least one set subsequent to the intermediate page, wherein the first and second page sequence definitions are expressed as a conditional choose function.