Pure grammars

A epting Pure Grammars

Accepting Pure Grammars and Systems

We consider several types of pure grammars and systems as language acceptors and compare them to their generating counterparts. In contrast with the case (considered in earlier papers of the authors) encountered when admitting nonterminals in these classical string rewriting mechanisms , we get incomparability results between language families generated and accepted by numerous types of pure gr...

Pattern Ambiguities for Pure Context{free Grammars Pattern Ambiguities for Pure Context{free Grammars Pattern Ambiguities for Pure Context{free Grammars

We consider here some special forms of ambiguity for pure context-free grammars, namely pattern avoiding ambiguity, pattern preserving ambiguity, pattern ambiguity, and grammar avoiding ambiguity. The rst two properties are undecidable for arbitrary pure context-free grammars, and in a particular but general enough case we can eeectively decide whether or not a pure context-free grammar is patt...

Pure 2D picture grammars and languages

A new syntactic model, called pure 2D context-free grammar (P2DCFG), is introduced based on the notion of pure context-free string grammar. The rectangular picture generative power of this 2D grammar model is investigated. Certain closure properties are obtained. An analogue of this 2D grammar model called pure 2D hexagonal context-free grammar (P2DHCFG) is also considered to generate hexagonal...

A pure embedding of attribute grammars

Attribute grammars are a powerful specification paradigm for many language processing tasks, particularly semantic analysis of programming languages. Recent attribute grammar systems use dynamic scheduling algorithms to evaluate attributes on demand. In this paper, we show how to remove the need for a generator, by embedding a dynamic approach in a modern, object-oriented and functional program...