pyslet QTI example: traversing a parsed tree

pyslet-traverse.py

from typing import Optional, Any, Sequence

import pyslet.qtiv2.xml as qti
from pyslet.xml.namespace import NSElement
from pyslet.xml.structures import Document, Element


def getChildElements(node: NSElement) -> Sequence[NSElement]:
    # skips strings not enclosed within elements (e.g., linebreaks in XML file)
    return [child for child in node.get_children() if
            isinstance(child, NSElement)]


def getAttr(node: NSElement, attrName: str, default: Any = None) -> \
        Optional[Any]:
    # gracefully return attribute value or substitute a default value
    try:
        return node.get_attribute(attrName)
    except KeyError:
        return default


def traverseChildTree(node: NSElement, depth=0, indentSize=2) -> None:
    children = getChildElements(node)
    if len(children) == 0:
        return
    indentation = ' ' * depth * indentSize
    for child in children:

        interestingAttributes = ['title', 'ident', 'respident']
        interestingAttrValues = {key: getAttr(child, key) for key in
                                 interestingAttributes if getAttr(child, key)}
        print(indentation + '; '.join([
            f'<{child.xmlname}>',

            f'attributes: {interestingAttrValues}',

            # ignore values that contain other elements,
            # those elements will be seen when traversing the next level
            f'value: "{child.get_value(ignore_elements=True).strip()}"']))
        traverseChildTree(child, depth=depth + 1)


if '__main__' == __name__:
    doc = qti.QTIDocument()

    with open('sample-test.xml', 'rb') as f:
        doc.read(src=f)
        root: Document = doc.root
        traverseChildTree(root)