Context-sensitive grammar

About: Context-sensitive grammar is a research topic. Over the lifetime, 1938 publications have been published within this topic receiving 45911 citations. The topic is also known as: CSG.

A Practical Bottom-Up Algorithm for On-Line Parsing with Stochastic Context-Free Grammars

Abstract: This article presents an on-line bottom-up parsing algorit hm for stochastic context-free grammars that, in addition to the usual functionalities of standard S CFG parsing algorithms, is able (1) to find theN -most probable parses of the input sequence; (2) to deal with multiple interpretations of sentences containing compound words; and (3) to deal with “out of vocabulary” words. Furthermore, the presented algorithm appears to be particular ly suitable for speech applications and is proved to be at least as efficient as the corresponding Earl ey-like or CYK-like algorithms. In terms of space complexity, even in the case where the number o f parse trees associated with a given input is exponential in its number of words ( n), the chart used by the algorithm for their representation remains O(n2) space complex.

Macros for context-free grammars

Abstract: Current parser generators are based on context-free grammars. Because such grammars lack abstraction facilities, the resulting specifications are often not easy to read. Fischer's macro grammars extend context-free grammars with macro-like productions thus providing the equivalent of procedural abstraction. However, their use is hampered by the lack of an efficient, off-the-shelf parsing technology for macro grammars. We define specialization for macro grammars to enable reuse of parsing technology for context-free grammars while facilitating the specification of a language with a macro grammar. This specialization yields context-free rules, but it does not always terminate. We present a sound and complete static analysis that applies to any macro grammar and decides whether specialization terminates for it and thus yields a (finite) context-free grammar. The analysis is based on an intuitive notion of self-embedding nonterminals, which is easy to check by hand. We have implemented the analysis as part of a preprocessing tool that transforms a Yacc grammar extended with macro productions to a standard Yacc grammar.

Equivalence and Reduction of Expansive Tree Grammars

Abstract: The equivalence of nonterminals of an expansive tree grammar is considered. Algorithms are presented for constructing sets of equivalent nonterminals for an expansive tree grammar, for reducing the grammar, and for determining whether two grammars generate the same language.