birdnotes.py: Objects to represent bird note files

The purpose of this method is to extract all the items of the taxon-group pattern from the XML form element, and use that to construct a new BirdForm instance. It is a static method because it is called from Section 12.7, “BirdForm.readNode() (static method)”, which is also a static method.

Refer to the schema for the definition of taxon-group.

# - - -   B i r d F o r m . g e t T a x o n G r o u p

    @staticmethod
    def getTaxonGroup(txny, dayNotes, node):
        """Convert the XML taxon-group pattern to a BirdForm instance.

          [ (txny is a bird taxonomy as a txny.Txny instance) and
            (dayNotes is the parent DayNotes instance) and
            (node is an et.Element) ->
              if node's taxon-group content defines a kind of bird
              valid in txny ->
                dayNotes  +:=   a new BirdForm instance made from node's
                    taxon-group content
                return that instance
              else -> raise KeyError ]
        """

First we extract the taxon-group items. The ab6 attribute is required; rel, alt, and notable are optional.

        #-- 1 --
        # [ ab6  :=  node's rnc.AB6_A attribute
        #   rel  :=  node's rnc.REL_A attribute, defaulting to None
        #   alt  :=  node's rnc.ALT_A attribute, defaulting to None
        #   notable  :=  node's rnc.NOTABLE_A attribute, defaulting
        #                to None ]
        ab6 = node.attrib[rnc.AB6_A]
        rel = node.attrib.get(rnc.REL_A, None)
        alt = node.attrib.get(rnc.ALT_A, None)
        notable = node.attrib.get(rnc.NOTABLE_A, None)

Next we must check that the code or codes are valid against the reference taxonomy.

        #-- 2
        # [ if (ab6, rel, alt) is a valid bird-id in txny ->
        #     birdId  :=  an abbrModule.BirdId instance representing
        #                 those values
        #   else -> raise KeyError ]
        birdId = abbrModule.BirdId(txny, ab6, rel, alt)

At this point we have everything we need to build a new BirdForm instance; see Section 12.5, “BirdForm.__init__()” for the constructor's calling sequence.

        #-- 2 --
        # [ dayNotes  +:=  a new BirdForm instance using ab6, rel,
        #       alt, and notable
        #   birdForm  :=  that new BirdForm instance ]
        birdForm = BirdForm(dayNotes, birdId, notable)

        #-- 3 --
        return birdForm