content.py 文件源码

def nest_annotations(annotations: Iterator[Annotation],
                     text_length: int) -> List[NestableAnnotation]:
    """Converts overlapping annotations into a nested version."""
    in_order = sorted(annotations, key=lambda a: (a.start, -a.end))
    # Easier to operate on a single root, even if we'll remove it later.
    root = last = NestableAnnotation(PlainText(start=0, end=text_length), None)
    for anote in in_order:
        # We're not allowing non-nested overlapping annotations, so we won't
        # compare ends when determining nesting
        while anote not in last:
            last = last.parent
        # Enforce all annotations to be nested rather than overlapping
        anote.end = min(anote.end, last.end)
        last = NestableAnnotation(anote, last)
    root.wrap_unwrapped()
    return root.children