‘Computed Fields’ have additional commands that allow behaviour based on the position of the field within a document:
TAGPAGENUMBER() – Returns the page number the tag is on, or -1 for the pasteboard
TAGPAGEX() – Returns the X position of the tag in points.
TAGPAGEY() – Returns the Y position of the tag in points.
TAGSPREADX() -Returns the X position of the tag on the spread in points.
TAGSPREADY() -Returns the Y position of the tag on the spread in points.
IMAGE(N) – Returns the Nth Image name from a field with a list of images separated by CR. The field name is implied from the Computed Field the command is used on.
TAGINSTANCE() – The instance number of this tag in the text flow, starting from 1.
CELLSTR(ROW,COL) – Returns the text contained in cell relative to the field position. Pass -1 to return the value of the current row or col, or 9999 for the last in the table.