【摘要】 模式的递归结构影响它的形式语言性质,成为模式结构描述的复杂问题之一。本文系统地研究了递归结构的性质,按基本递归结构划分子模式,并以句法-词义方法对它们作分层文法描述,从而建立了递归结构的有效描述体系。程序文法、属性文法以及由此派生的递归条件文法和递归属性文法,都能成功地按此体系描述各种递归结构,这些文法的描述能力也因而得到阐明。更多还原

【Abstract】 One of the complicated problems of pattern description is the effect of recursive structures on the nature of a pattern as a class of the formal language. In the present paper the properties of different recursive structures have been investigated. A strategy of hierachical syntacticsemantic description has been studied by dividing a pattern into subpatterns according to its basic recursive structures. Thus, a systematic and effective approach for describing recursive patterns has been suggested. The approach can be successfully applied to context-free programmed grammars, attributed grammars and two special types of modifications, namely, recursion-conditioned and recursion-attributed grammars. Their descriptive power for recursive structures has been discussed.更多还原