directives.py 文件源码

def __call__(self, stream, directives, ctxt, **vars):
        def _generate():
            kind, (tag, attrib), pos  = stream.next()
            attrs = _eval_expr(self.expr, ctxt, vars)
            if attrs:
                if isinstance(attrs, Stream):
                    try:
                        attrs = iter(attrs).next()
                    except StopIteration:
                        attrs = []
                elif not isinstance(attrs, list): # assume it's a dict
                    attrs = attrs.items()
                attrib |= [
                    (QName(n), v is not None and unicode(v).strip() or None)
                    for n, v in attrs
                ]
            yield kind, (tag, attrib), pos
            for event in stream:
                yield event

        return _apply_directives(_generate(), directives, ctxt, vars)