Python XML processing with lxml

This method is called when the user calls the factory instance E.

# - - -   E l e m e n t M a k e r . _ _ c a l l _ _

    def __call__(self, tag, *argList, **attr):
        '''Handle calls to a factory instance.
        '''

First we create a new, empty element with the given tag name.

        #-- 1 --
        # [ elt  :=  a new et.Element with name (tag) ]
        elt  =  et.Element(tag)

If the attr dictionary has anything in it, we can use the function stored in self.__typeMap[dict] to process those attributes.

        #-- 2 --
        # [ elt  :=  elt with attributes made from the key-value
        #            pairs in attr ]
        #   else -> I ]
        if attr:
            self.__typeMap[dict](elt, attr)

Next, process the positional arguments in a loop, using each argument's type to extract from self.__typeMap the proper handler for that type. For this logic, see Section 14.10, “ElementMaker.__handleArg(): Process one positional argument”.

        #-- 3 --
        # [ if the types of all the members of pos are also
        #   keys in self.__typeMap ->
        #       elt  :=  elt modified as per the corresponding
        #                functions from self.__typeMap
        #   else -> raise TypeError ]
        for arg in argList:
            #-- 3 body --
            # [ if type(arg) is a key in self.__typeMap ->
            #     elt  :=  elt modified as per self.__typeMap[type(arg)]
            #   else -> raise TypeError ]
            self.__handleArg(elt, arg)

Finally, return the shiny new element to the caller.

        #-- 4 --
        return elt