Analyzing ambiguity of context-free grammars

作者：Brabrand Claus; Giegerich Robert; Moller Anders^*

来源：Science of Computer Programming, 2010, 75(3): 176-191.

DOI：10.1016/j.scico.2009.11.002

• Context-free languages
• Approximation
• Biosequence analysis

It has been known since 1962 that the ambiguity problem for context-free grammars is undecidable. Ambiguity in context-free grammars is a recurring problem in language design and parser generation, as well as in applications where grammars are used as models of real-world physical structures.
We observe that there is a simple linguistic characterization of the grammar ambiguity problem, and we show how to exploit this by presenting an ambiguity analysis framework based on conservative language approximations. As a concrete example, we propose a technique based on local regular approximations and grammar unfoldings. We evaluate the analysis using grammars that occur in RNA analysis in bioinformatics, and we demonstrate that it is sufficiently precise and efficient to be practically useful.

• 出版日期2010-3