Adcs 2010

Wikimedia article archives (Wikipedia, Wiktionary, and so on) assemble open-access, authoritative corpora for semantic-informed datamining, machine learning, information retrieval, and natural language processing. In this paper, we show the MediaWiki wikitext grammar to be context-sensitive, thus precluding application of simple parsing techniques. We show there exists a worst-case bound on time complexity for all fully compliant parsers, and that this bound makes parsing intractable as well as constituting denial-of-service (DoS) and degradation-of-service (DegoS) attacks against all MediaWiki wikis. We show there exists a worse-case bound on storage complexity for fully compliant onepass parsing, and that contrary to expectation such parsers are no more scalable than equivalent two-pass parsers. We claim these problems to be the product of deficiencies in the MediaWiki wikitext grammar and, as evidence, comparatively review 10 contemporary wikitext parsers for noncompliance with a partially compliant Parsing Expression Grammar (PEG).