The automatic inversion of attribute grammars

Attribute grammars constitute a formal mechanism for specifying translations between languages; from a formal description of the translation, a translator can be automatically constructed. This process is taken one step further; given an attribute grammar specifying the translation from language L₁ to language L₂, the question of whether the inverse attribute grammar specifying the inverse translation from L₂ to L₁ can be automatically generated is addressed. It is shown how to solve this problem for a restricted subset of attribute grammars. This inversion process allows compatible two-way translators to be generated from a single description. To show the practical feasibility of attribute grammar inversion, experience in inverting an attribute grammar used as an interface for a formal database accessing language, SQL, is related. The attributed grammar is used to paraphrase SQL database queries in English.