An extension of earley's algorithm for S-attributed grammars

Correa, Nelson Becerra

doi:10.3115/977180.977232

Cited by 5 publications

(9 citation statements)

References 15 publications

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“…A transition is enabled along a predicate edge when the predicate in question evaluates to true in the current environment. 3 The edges enclosed in curly braces are assignment edges -traversing the edge from 3 to 1 assigns n−1 to n. Lastly, notice that the final state for this automaton (final states are marked by double-circles) is labelled with the nonterminal int. Final states may, in general, be labelled with many nonterminals -arrival at such a state signals simultaneous completion of multiple nonterminal definitions.…”

Section: Data-dependent Automatamentioning

confidence: 99%

“…Watt introduced the idea of directed parsing [33], and applied it to the LR fragment of context-free languages. Correa [3] and Tokuda and Watanabe [31] have extended Earley's algorithm to L-attributed grammars, though omitting features such as our environments, regular right sides, and blackboxes; Correa implemented attribute-directed parsing.…”

Section: Related Workmentioning

confidence: 99%

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Semantics and algorithms for data-dependent grammars

Jim

Mandelbaum

Walker

2010

Proceedings of the 37th Annual ACM SIGPLAN-SIGACT Symposium on Principles of Programming Languages

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Traditional parser generation technologies are incapable of handling the demands of modern programmers. In this paper, we present the design and theory of a new parsing engine, YAKKER, capable of handling the requirements of modern applications including (1) full scannerless context-free grammars with (2) regular expressions as right-hand sides for defining nonterminals. YAKKER also includes (3) facilities for binding variables to intermediate parse results and (4) using such bindings within arbitrary constraints to control parsing. These facilities allow the kind of data-dependent parsing commonly needed in systems applications, particularly those that operate over binary data. In addition, (5) nonterminals may be parameterized by arbitrary values, which gives the system good modularity and abstraction properties in the presence of data-dependent parsing. Finally, (6) legacy parsing libraries, such as sophisticated libraries for dates and times, may be directly incorporated into parser specifications. We illustrate the importance and utility of this rich format specification language by presenting its use on examples ranging from difficult programming language grammars to web server logs to binary data specification. We also show that our grammars have important compositionality properties and explain why such properties are important in modern applications such as automatic grammar induction.In terms of technical contributions, we provide a traditional high-level semantics for our new grammar formalization and show how to compile these grammars into nondeterministic automata. These automata are stack-based, somewhat like conventional pushdown automata, but are also equipped with environments to track data-dependent parsing state. We prove the correctness of our translation of data-dependent grammars into these new automata and then show how to implement the automata efficiently using a variation of Earley's parsing algorithm.

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Section: Data-dependent Automatamentioning

confidence: 99%

Section: Related Workmentioning

confidence: 99%

Semantics and algorithms for data-dependent grammars

Jim

Mandelbaum

Walker

2010

Proceedings of the 37th Annual ACM SIGPLAN-SIGACT Symposium on Principles of Programming Languages

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“…The two attribute conditions, in the first and fourth productions, refer to the values of these attributes and could easily be assimilated to synthesized attributes. See [14] for a typical Earley-style derivation according to this grammar.…”

Section: S ----> Np Vpmentioning

confidence: 99%

“…Tomita [39] also presents an efficient parsing algorithm for augmented context-free grammars, based on a generalization of LR parsing techniques. The extension of Correa [ 14] does on-line attribute evaluation, allows for ambiguous and even cyclic bases, and is sufficient for S-and L-attributed grammars. Yellin's [42] technique requires a cycle-free base and allows any (well-defined) attributions, but it handles the attribute evaluation off-line, in up to two phases after syntactic analysis.…”

Section: Introductionmentioning

confidence: 99%

“…for natural languages) has only recently begun to be worked out. Current work by the author [14] and by Yellin [42] addresses the problem of ambiguous underlying syntax by an extension of Earley's algorithm or generalized attributed parsing. Tomita [39] also presents an efficient parsing algorithm for augmented context-free grammars, based on a generalization of LR parsing techniques.…”

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confidence: 99%

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Attribute and unification grammar: A review and analysis of formalisms

Correa

1993

Ann Math Artif Intell

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Attribute and unification grammar are syntax-directed grammatical formalisms that bear an important resemblance to each other and, especially in the case of unification grammar, enjoy certain currency as tools for linguistic description. A systematic study and comparison of the two formalisms, however, has not been reported to date. This paper reviews and compares the two formalisms, both from the point of view of their notations and expressive capabilities, and from that of their underlying algebraic semantics. The key to the semantic comparison is an algebraic formulation of the semantics of unification and the algebraic semantics of attribute grammar developed by Chirica and Martin [6]. The main result is that, from the point of view of their definitions and semantics, attribute grammar is more general than unifieatiun grammar, since it rests on a richer semantic algebra. This greater generality has important implications regarding the expressive power of the formalism and the possibility of efficient computational implementations for it. Also regarding their semantics, it is revealed that attribute grammar, unlike unification grammar, does not restrict attribute values to their basic term interpretation. This is a double-edged sword which, on the one hand, makes attribute grammar expressive and computationaUy efficient and, on the other, makes it computationally difficult to implement, because of the so-called "attribute evaluation problem". For unification grammar, the noted restriction on term interpretations is at the heart of the difficulties encountered in implementing such linguistically motivated extensions to the basic formalism as negation and disjunction. The conclusion of this study is that attribute grammar is a better suited and more highly developed grammatical formalism for the description of natural and artificial languages, due to its greater generality, expressive power and, also importantly, more efficient computational implementations. IntroductionAttribute grammar [29] is an elegant formalization of the augmented contextfree grammars found in most current natural language systems. It bears an important resemblance to the attribute-value of "complex-feature-based" approaches to language which rely on unification in their underlying interpretation [28,33]. While in attribute grammar (AG) attribute values and conditions are defined declaratively by a set of J.C. Baltzer AG, Science Publishers 74 N. Correa, Attribute and unification grammar attribution rules and conditions associated with each production in the grammar, and attribute evaluation is heavily dependent on the modes of the attributes and the data dependencies introduced by the rules used to define their values, in unificationbased formalisms (UG), unification of label-value structures serves the dual role of defining attribute values and conditions, and attribute evaluation amounts to the solution of a system of equations on the attribute-value structures, imposed by the particular derivation of the input string. Both form...

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An ASIC CAM design for associative set processors

Correa

García

Duarte

et al.

[1991] Proceedings Fourth Annual IEEE International ASIC Conference and Exhibit

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One of the key requirements in systems for symbolic computation is the fast and efficient execution of set operations, such as addition, removal, or test for membership of an element in a given set S . Contentaddressable memory (CAM) offers the potential for massive fine-grained parallelism in the implementation of these operations, yielding a potential speedup of O(I SI). This paper describes an ASIC design of a 32x32 CMOS static CAM for use in an associative set processor.

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An extension of earley's algorithm for S-attributed grammars

Cited by 5 publications

References 15 publications

Semantics and algorithms for data-dependent grammars

Semantics and algorithms for data-dependent grammars

Attribute and unification grammar: A review and analysis of formalisms

An ASIC CAM design for associative set processors

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