birdnotes.py: Objects to represent bird note files

This method builds a Sighting instance from a form element when there are no child floc elements.

# - - -   B i r d F o r m . s i n g l e S i g h t i n g

    def singleSighting(self, dayNotes, node):
        """Build a Sighting child for the single-sighting case.

          [ (dayNotes is the parent DayNotes instance) and
            (node is an rnc.FORM_N node) ->
              self  :=  self with a single Sighting child added,
                  made from node's age-sex-group, loc-group, and
                  sighting-notes content ]
        """

See Section 13.1, “Sighting.__init__()” for the constructor.

        #-- 1 --
        # [ sighting  :=  a new, empty Sighting instance with
        #                 self as the parent ]
        sighting = Sighting(self)

Next, check for loc-group content. If there is any, and it has a loc attribute, we'll also need to be sure that location code is defined. See Section 14.2, “LocGroup.readNode(): Extract loc-group content” and Section 8.4, “DayNotes.lookupLoc(): Look up a location code”.

        #-- 2 --
        # [ if node has any valid loc-group content ->
        #     sighting.locGroup  :=  that content as a LocGroup
        #                            instance
        #   else if node loc-group content with a loc that is
        #   not in dayNotes ->
        #     raise IOError
        #   else ->
        #     sighting.locGroup  :=  None ]
        sighting.locGroup = LocGroup.readNode(node, dayNotes)

The other two kinds of content proceed similarly. See Section 15.2, “AgeSexGroup.readNode() (static method)” and Section 16.5, “SightNotes.readNode() (static method)”.

        #-- 3 --
        # [ if  node has any age-sex-group content ->
        #     sighting.ageSexGroup  :=  a new AgeSexGroup
        #         instance representing that content
        #   else ->
        #     sighting.ageSexGroup  :=  None ]
        sighting.ageSexGroup = AgeSexGroup.readNode(node)

        #-- 4 --
        # [ if node has any sighting-notes content ->
        #     sighting.sightNotes  :=  a new SightNotes instance
        #         representing that content
        #   else ->
        #     sighting.sightNotes  :=  None ]
        sighting.sightNotes = SightNotes.readNode(node)