Tree-adjoining grammar

About: Tree-adjoining grammar is a research topic. Over the lifetime, 2491 publications have been published within this topic receiving 57813 citations.

An extension of context-free grammars with one-sided context specifications

Abstract: The paper introduces an extension of context-free grammars equipped with an operator for referring to the left context of the substring being defined. For example, a rule A->[email protected]?B defines a symbol a, as long as it is preceded by a string defined by B. The conjunction operator in this example is taken from conjunctive grammars (Okhotin, 2001), which are an extension of ordinary context-free grammars that maintains most of their practical properties, including many parsing algorithms. This paper gives two equivalent definitions of grammars with left contexts-by logical deduction and by language equations-and establishes their basic properties, including a transformation to a normal form and a cubic-time parsing algorithm, with a square-time version for unambiguous grammars.

Unambiguous Boolean grammars

Abstract: Boolean grammars are an extension of context-free grammars, in which conjunction and negation may be explicitly used in the rules In this paper, the notion of ambiguity in Boolean grammars is defined It is shown that the known transformation of a Boolean grammar to the binary normal form preserves unambiguity, and that every unambiguous Boolean language can be parsed in time O(n^2) Linear conjunctive languages are shown to be unambiguous, while the existence of languages inherently ambiguous with respect to Boolean grammars is left open

Graph Grammar Induction on Structural Data for Visual Programming

Abstract: Computer programs that can be expressed in two or more dimensions are typically called visual programs. The underlying theories of visual programming languages involve graph grammars. As graph grammars are usually constructed manually, construction can be a time-consuming process that demands technical knowledge. Therefore, a technique for automatically constructing graph grammars - at least in part - is desirable. An induction method is given to infer node replacement graph grammars. The method operates on labeled graphs of broad applicability. It is evaluated by its performance on inferring graph grammars from various structural representations. The correctness of an inferred grammar is verified by parsing graphs not present in the training set