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Context-Free Grammars with Lookahead
2021We introduce context-free grammars with lookahead. The grammars are an extension of both context-free grammars and parsing expression grammars, hence we can handle the two grammars in a unified way. To accommodate lookahead, we use a language with lookahead, which is a set of string pairs. We considered the grammar as a system of equations and give the
Takayuki Miyazaki, Yasuhiko Minamide
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Acta Informatica, 1994
A text is a tripleτ=(λ,ρ1,ρ2) such that λ is a labeling function, andρ1 andρ2 are linear orders on the domain of λ; hence τ may be seen as a word (λ,ρ1) together with an additional linear orderρ2 on the domain of λ. The orderρ2 is used to give to the word (λ,ρ1) itsindividual hierarchical representation (syntactic structure) which may be a tree but it ...
P. ten Pas +2 more
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A text is a tripleτ=(λ,ρ1,ρ2) such that λ is a labeling function, andρ1 andρ2 are linear orders on the domain of λ; hence τ may be seen as a word (λ,ρ1) together with an additional linear orderρ2 on the domain of λ. The orderρ2 is used to give to the word (λ,ρ1) itsindividual hierarchical representation (syntactic structure) which may be a tree but it ...
P. ten Pas +2 more
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1993
Context-free grammars are a language for defining languages. Not all languages can be defined by a context-free grammar — only the (yes) context-free ones. Suppose we want to define the language of a small child, who continually says sentences like “want cookie”. His or her sentences consist of a verb followed by a noun.
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Context-free grammars are a language for defining languages. Not all languages can be defined by a context-free grammar — only the (yes) context-free ones. Suppose we want to define the language of a small child, who continually says sentences like “want cookie”. His or her sentences consist of a verb followed by a noun.
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Indexed Grammars—An Extension of Context-Free Grammars
Journal of the ACM, 1967A 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.
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A REGULARITY CONDITION FOR CONTEXT-FREE GRAMMARS
International Journal of Foundations of Computer Science, 2008We define a complexity measure on context-free grammars called end. Roughly speaking, for a context-free grammar G, endG(n) measures the distance of variables from the ends of sentential forms along the derivations of words in L(G) of length n. We prove in a constructive way the regularity of L(G)wheneverendG(n)is constant.
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On context-free programmed grammars
Computer Languages, 1989Abstract We develop a definition of a deterministic and decidable class of context-free programmed grammars, the SPG class. A table-driven parsing algorithm that operates in quadratic time and an algorithm to produce the parsing table from a given grammar are included.
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Context-Free Grammars and Languages
1977You may have seen something like the following used to give a formal defini-tion of a language. This notation is sometimes called BNF for Backus-Naur form.
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Context-free grammars on trees
Proceedings of the first annual ACM symposium on Theory of computing - STOC '69, 1969In this paper we discuss still another version of indexed grammars 1 and macro grammars3,gaining some geometric intuition about the structure of these systems. An ordinary context-free grammar is a rewriting system for strings; we find that a macro grammar is a rewriting system for trees.
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The Polytope of Context-Free Grammar Constraints
2009Context-free grammar constraints enforce that a sequence of variables forms a word in a language defined by a context-free grammar. The constraint has received a lot of attention in the last few years as it represents an effective and highly expressive modeling entity.
Claude-Guy Quimper +3 more
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Lambek grammars are context free
[1993] Proceedings Eighth Annual IEEE Symposium on Logic in Computer Science, 2002Basic categorial grammars are the context-free ones. Another kind of categorial grammars was introduced by J. Lambek (1958). These grammars are based on a syntactic calculus, known as the Lambek calculus. Chomsky (1963) conjectured that these grammars are also equivalent to context-free ones.
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