Answers are grounded in this paper and cite their sources.
New grammar type introduces indexed grammars for formal languages, indicating broader language generation capabilities.
A new type of grammar for generating formal languages, called an indexed grammar, is presented. An indexed grammar is an extension of a context-free grammar, and the class of languages generated by indexed grammars has closure properties and decidability results similar to those for context-free languages. The class of languages generated by indexed grammars properly includes all context-free languages and is a proper subset of the class of context-sensitive languages. Several subclasses of indexed grammars generate interesting classes of languages.
No takes yet. Share an insight, caveat, or question.
Alfred V. Aho (1968) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: