{'fraction_non_alphanumeric': 0.032915360501567396, 'fraction_numerical': 0.0, 'mean_word_length': 4.916666666666667, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Compression vs Queryability - A Case Study

Some compromise on compression is known to be necessary, if the relative positions of the information stored by semi-structured documents are to remain accessible under queries. With this in view, we compare, on an example, the ‘query-friendliness’ of XML documents, when compressed into straightline tree grammars which are either regular or context-free. The queries considered are in a limited fragment of XPath, corresponding to a type of patterns; each such query defines naturally a non-deterministic, bottom-up ‘query automaton’ that runs just as well on a tree as on its compressed dag.