Showing papers on "L-attributed grammar published in 1986"
TL;DR: A formal model of the mental representation of task languages is presented, a metalanguage for defining task-action grammars (TAG) that rewrite simple tasks into action specifications that make predictions about the relative learnability of different task language designs.
Abstract: A formal model of the mental representation of task languages is presented. The model is a metalanguage for defining task-action grammars (TAG): generative grammars that rewrite simple tasks into action specifications. Important features of the model are (a) Identification of the "simple-tasks" that users can perform routinely and that require no control structure; (b) Representation of simple-tasks by collections of semantic components reflecting a categorization of the task world; (c) Marking of tokens in rewrite rules with the semantic features of the task world to supply selection restrictions on the rewriting of simple-tasks into action specifications. This device allows the representation of family resemblances between individual task-action mappings. Simple complexity metrics over task-action grammars make predictions about the relative learnability of different task language designs. Some empirical support for these predictions is derived from the existing empirical literature on command language learning, and from two unreported experiments. Task-action grammars also provide designers with an analytic tool for exposing the configural properties of task languages.
328 citations
TL;DR: The problem of grammatical inference is introduced, and its potential engineering applications are demonstrated, andference algorithms for finite-state and context-free grammars are presented.
Abstract: Inference of high-dimensional grammars is discussed. Specifically, techniques for inferring tree grammars are briefly presented. The problem of inferring a stochastic grammar to model the behavior of an information source is also introduced and techniques for carrying out the inference process are presented for a class of stochastic finite-state and context-free grammars. The possible practical application of these methods is illustrated by examples.
189 citations
01 May 1986
TL;DR: Some new results for TAG's are described, especially in the following areas: parsing complexity of TAG's, some closure results forTAG's, and the relationship to Head grammars.
Abstract: Tree Adjoining Grammar (TAG) is a formalism for natural language grammars. Some of the basic notions of TAG's were introduced in [Joshi, Levy, and Takahashi 1975] and by [Joshi, 1983]. A detailed investigation of the linguistic relevance of TAG's has been carried out in [Kroch and Joshi, 1985]. In this paper, we will describe some new results for TAG's, especially in the following areas: (1) parsing complexity of TAG's, (2) some closure results for TAG's, and (3) the relationship to Head grammars.
107 citations
01 Jul 1986
TL;DR: This paper presents constraints on individual attributes and semantic functions of an AG that are sufficient to guarantee that a circular AG specifies a well-defined translation and that circularly-defined attribute-instances can be computed via successive approximation.
Abstract: In the traditional formulation of attribute grammars (AGs) circularities are not allowed, that is, no attribute-instance in any derivation tree may be defined in terms of itself Elsewhere in mathematics and computing, though, circular (or recursive) definitions are commonplace, and even essential Given appropriate constraints, recursive definitions are well-founded, and the least fixed-points they denote are computable This is also the case for circular AGsThis paper presents constraints on individual attributes and semantic functions of an AG that are sufficient to guarantee that a circular AG specifies a well-defined translation and that circularly-defined attribute-instances can be computed via successive approximation AGs that satisfy these constraints are called finitely recursiveAn attribute evaluation paradigm is presented that incorporates successive approximation to evaluate circular attribute-instances, along with an algorithm to automatically construct such an evaluator The attribute evaluators so produced are static in the sense that the order of evaluation at each production-instance in the derivation-tree is determined at the time that each translator is generatedA final algorithm is presented that tells which individual attributes and functions must satisfy the constraints
95 citations
01 Jan 1986
TL;DR: New attribute-grammar-based methods that allow the updating algorithm to skip over arbitrarily large sections of the tree that more straightforward updating methods visit node by node, and are extended to deal with aggregate values.
Abstract: A major drawback to the use of attribute grammars in language-based editors has been that attributes can only depend on neighboring attributes in a program's syntax tree. This paper concerns new attribute-grammar-based methods that, for a suitable class of grammars, overcome this fundamental limitation. The techniques presented allow the updating algorithm to skip over arbitrarily large sections of the tree that more straightforward updating methods visit node by node. These techniques are then extended to deal with aggregate values, so that the attribute updating procedure need only follow dependencies due to a changed component of an aggregate value. Although our methods work only for a restricted class of attribute grammars, satisfying the necessary restrictions should not place an undue burden on the writer of the grammar.
70 citations
Book•
01 Jan 1986
TL;DR: It is shown how some transformations of functional programs may be better understood by viewing the programs as inefficient implementations of attribute grammars.
Abstract: Two mappings from attribute grammars to lazy functional programs are defined. One of these mappings is an efficient implementation of attribute grammars. The other mapping yields inefficient programs. It is shown how some transformations of functional programs may be better understood by viewing the programs as inefficient implementations of attribute grammars.
49 citations
01 Jan 1986
TL;DR: This work introduces copy bypass attribute propagation that dynamically replaces copy rules with nonlocal dependencies, resulting in faster incremental evaluation that allows multiple subtree replacement on any noncircular attribute grammar.
Abstract: Attribute grammars require copy rules to transfer values between attribute instances distant in an attributed parse tree. We introduce copy bypass attribute propagation that dynamically replaces copy rules with nonlocal dependencies, resulting in faster incremental evaluation. A evaluation strategy is used that approximates a topological ordering of attribute instances. The result is an efficient incremental evaluator that allows multiple subtree replacement on any noncircular attribute grammar.
39 citations
25 Aug 1986
TL;DR: It is shown that Head Languages are included in Tree Adjoining Languages and that Tree Adjoined Grammars are equivalent to a modification of Head Grammar called Modified Head GramMars.
Abstract: In this paper we discuss the formal relationship between thw classes of languages generated by Tree Adjoining Grammars and Head Grammars. In particular, we show that Head Languages are included in Tree Adjoining Languages and that Tree Adjoining Grammars are equivalent to a modification of Head Grammars called Modified Head Grammars. The inclusion of MHL in HL, and thus the equivalence of HG's and TAG's in the most general case remains to be established.
38 citations
32 citations
01 Jul 1986
TL;DR: This work presents efficient algorithms for incrementally maintaining aggregate values and gives an incremental evaluation algorithm that restricts attribute propagation to attributes dependent only upon information within the aggregate value that has changed.
Abstract: Aggregate valued attributes, which store collections of keyed elements, are required in attribute grammars to communicate information from multiple definition sites to multiple use locations. For syntax directed editors and incremental compilers, symbol tables are represented as aggregate values. We present efficient algorithms for incrementally maintaining these aggregate values and give an incremental evaluation algorithm that restricts attribute propagation to attributes dependent only upon information within the aggregate value that has changed.
31 citations
TL;DR: The complexity of (the membership problem for) the class of regular DNLC grammars is investigated and it is found that it provides a useful framework for the theory of concurrent systems based on the Theory of traces.
TL;DR: It is shown that the output language (i.e., the range of the translation) of a SAG is log-space reducible to a context-free language.
Abstract: A string-valued attribute grammar (SAG) has a semantic domain of strings over some alphabet, with concatenation as basic operation. It is shown that the output language (i.e., the range of the translation) of a SAG is log-space reducible to a context-free language.
IBM1
TL;DR: An effective method for the execution of recursive attribute grammars has been defined and applied and generated Prolog code stands in direct relation to its attribute grammar.
Abstract: This paper describes an algorithm for compiling attribute grammars into Prolog. The attribute grammars may include inherited and synthesized attributes and contain recursive (circular) definitions. The semantics of the recursive definitions is defined in terms of a fixed-point finding function. The generated Prolog code stands in direct relation to its attribute grammar, where logical variables play the role of synthesized or inherited attributes. Thus an effective method for the execution of recursive attribute grammars has been defined and applied.
10 Jul 1986
TL;DR: The absence of mirror-image constructions in human languages means that it is not enough to extend Context-free Grammars in the direction of context-sensitivity, and a class of grammars must be found which handles (context-sensitive) copying but not ( context-free) mirror images, suggesting that human linguistic processes use queues rather than stacks.
Abstract: The documentation of (unbounded-length) copying and cross-serial constructions in a few languages in the recent literature is usually taken to mean that natural languages are slightly context-sensitive. However, this ignores those copying constructions which, while productive, cannot be easily shown to apply to infinite sublanguages. To allow such finite copying constructions to be taken into account in formal modeling, it is necessary to recognize that natural languages cannot be realistically represented by formal languages of the usual sort. Rather, they must be modeled as families of formal languages or as formal languages with indefinite vocabularies. Once this is done, we see copying as a truly pervasive and fundamental process in human language. Furthermore, the absence of mirror-image constructions in human languages means that it is not enough to extend Context-free Grammars in the direction of context-sensitivity. Instead, a class of grammars must be found which handles (context-sensitive) copying but not (context-free) mirror images. This suggests that human linguistic processes use queues rather than stacks, making imperative the development of a hierarchy of Queue Grammars as a counterweight to the Chomsky Grammars. A simple class of Context-free Queue Grammars is introduced and discussed.
TL;DR: This work adapts the theory of probabilistic grammars to the prediction of switchpoint abundance for a given bilingual situation and applies this to a number of language pairs exhibiting diverse word-order contrasts.
Abstract: How can we combine the grammars of two languages to model bilingual behaviour such as code-switching under the equivalence constraint on word order? We answer this question on the formal level, making use of context-free grammars for both unilingual and bilingual behaviour. Our solution satisfies a number of conditions on the language assigned (if any) to higher-order constituents in the phrase structure. Bilingual sentences are seen to be often ambiguous with respect to this assignment. We adapt the theory of probabilistic grammars to the prediction of switchpoint abundance for a given bilingual situation and we apply this to a number of language pairs exhibiting diverse word-order contrasts. We show how to count the number of bilingual sentences which are code-switched equivalents of a given sentence.
10 Jul 1986
TL;DR: The relationship between the two grammatical formalisms: Tree Adjoining Grammars and Head Grammar is examined and a discussion comparing the linguistic expressiveness of the two formalisms is discussed.
Abstract: We examine the relationship between the two grammatical formalisms: Tree Adjoining Grammars and Head Grammars. We briefly investigate the weak equivalence of the two formalisms. We then turn to a discussion comparing the linguistic expressiveness of the two formalisms.
TL;DR: This report investigates the problem of efficient representation of the attributed parse tree by analyzing and comparing the strategies of two systems that have been used to automatically generate a translator from an attribute grammar: the GAG system developed at the Universitat de Karlsruhe and the LINGUIST-86 system written at Intel Corporation.
Abstract: Attribute grammars are a value-oriented, non-procedural extension to context-free grammars that facilitate the specification of translations whose domain is described by the underlying context-free grammar. Just as parsers for context-free languages can be automatically constructed from a context-free grammar, so can translators, called attribute evaluators, be automatically generated from an attribute grammar. A major obstacle to generating efficient attribute evaluators is that they typically use large amounts of memory to represent the attributed parse tree. In this report we investigate the problem of efficient representation of the attributed parse tree by analyzing and comparing the strategies of two systems that have been used to automatically generate a translator from an attribute grammar: the GAG system developed at the Universitat de Karlsruhe and the LINGUIST-86 system written at Intel Corporation. Our analysis will characterize the two strategies and highlight their respective strengths and weaknesses. Drawing on the insights given by this analysis, we propose a strategy for storage optimization in automatically generated attribute evaluators that not only incorporates the best features of both GAG and LINGUIST-86, but also contains novel features that address aspects of the problem that are handled poorly by both systems.
Proceedings Article•
11 Aug 1986
TL;DR: The reasoning behind the selection and design of a parser for the Lingo project on natural language interfaces at MCC is presented, and a variant of chart parsing that uses a best-first control structure managed on an agenda as a control structure is chosen.
Abstract: This paper presents the reasoning behind the selection and design of a parser for the Lingo project on natural language interfaces at MCC. The major factors in the selection of the parsing algorithm were the choices of having a syntactically based grammar, using a graph-unification-based representation language, using Combinatory Categorial Grammars, and adopting a one-to-many mapping from syntactic bracketings to semantic representations in certain cases. The algorithm chosen is a variant of chart parsing that uses a best-first control structure managed on an agenda. It offers flexibility for these natural language processing applications by allowing for best-first tuning of parsing for particular grammars in particular domains while at the same time allowing exhaustive enumeration of the search space during grammar development. Efficiency advantages of this choice for graph-unification-based representation languages are outlined, as well as a number of other advantages that acrue to this approach by virtue of its use of an agenda as a control structure. We also mention two useful refinements to the basic best-first chart parsing algorithm that have been implemented in the Lingo project.
TL;DR: A shape grammar formalism which accounts for most aspects of 2-D shape, a parsing mechanism which uses constraints between pieces of the shape, and an automatic method to compute constraint relations between the vocabulary symbols of theshape grammar are proposed.
01 Aug 1986-Graphical Models \/graphical Models and Image Processing \/computer Vision, Graphics, and Image Processing
TL;DR: This paper investigates the basic properties of the class of neighborhood-uniform nodel label controlled (NUNLC) graph grammars and demonstrates that a number of basic properties are decidable for theclass of NUNLC grammar—many of them are undecidable in the whole class of NLC Grammars.
Abstract: This paper investigates the basic properties of the class of neighborhood-uniform nodel label controlled (NUNLC) graph grammars The class of NUNLC grammars is distinguished by requiring a very natural restriction on the connection relations of NLC grammars The restriction implies “Church-Rosser property” of derivations in an NUNLC grammar, which makes the class of NUNLC grammars “technically easier” to investigate A number of combinatorial properties of the languages generated by the class of NUNLC grammars are proved Also, it is demonstrated that a number of basic properties are decidable for the class of NUNLC grammars—many of them are undecidable in the whole class of NLC grammars
25 Aug 1986
TL;DR: The weak generative capacity of a class of parenthesis free categorial grammars derived from those of Ades and Steedman are studied by varying the set of reduction rules and a context sensitive language is obtained.
Abstract: We study the weak generative capacity of a class of parenthesis free categorial grammars derived from those of Ades and Steedman by varying the set of reduction rules. With forward cancellation as the only rule, the grammars are weakly equivalent to context free grammars. When a backward combination rule is added, it is no longer possible to obtain all the context-free language. With suitable restriction of the forward partial rule, the languages are still context-free and a push-down automaton can be used for recognition. Using the unrestricted rule of forward partial combination, a context sensitive language is obtained.
01 Jul 1986
TL;DR: An extension of attribute grammars is introduced that supports the generation of run-time environments and also supports thegeneration of interpreters, symbolic debugging tools, and other execution-time facilities.
Abstract: Attribute grammars have been used for many years for automated compiler construction. Attribute grammars support the description of semantic analysis, code generation and some code optimization in a formal declarative style. Other tools support the automation of lexical analysis and parsing. However, there is one large part of compiler construction that is missing from our toolkit: run-time environments. This paper introduces an extension of attribute grammars that supports the generation of run-time environments. The extension also supports the generation of interpreters, symbolic debugging tools, and other execution-time facilities.
TL;DR: To show the practical feasibility of attribute grammar inversion, experience in inverting an attribute grammar used as an interface for a formal database accessing language, SQL, is related; the attributed grammar is used to paraphrase SQL database queries in English.
Abstract: Attribute grammars constitute a formal mechanism for specifying translations between languages; from a formal description of the translation, a translator can be automatically constructed. This process is taken one step further; given an attribute grammar specifying the translation from language L1 to language L2, the question of whether the inverse attribute grammar specifying the inverse translation from L2 to L1 can be automatically generated is addressed. It is shown how to solve this problem for a restricted subset of attribute grammars. This inversion process allows compatible two-way translators to be generated from a single description. To show the practical feasibility of attribute grammar inversion, experience in inverting an attribute grammar used as an interface for a formal database accessing language, SQL, is related. The attributed grammar is used to paraphrase SQL database queries in English.
TL;DR: A powerful method of parsing is presented, that suits particularly well the Graham-Glanville code generation methodology and can be applied to any prefix grammar.
Abstract: A powerful method of parsing is presented, that suits particularly well the Graham-Glanville code generation methodology. This parsing method can be applied to any prefix grammar. It is shown how a table is generated and used to achieve parsing efficiency.
TL;DR: It is shown that the direction-independent restriction does not affect the generative powers of MAG, but it does, however, affect theGenerative power of a restricted version of ∗AG, i.e., connected ∗-array grammars.
TL;DR: This work has shown that Parser tables of predictive LL-parsers for extended grammars can be generated very efficiently if the length of look-ahead is 1 and the generation time is proportional to the size of the parser table.
Abstract: Extended context-free grammars also called regular right part grammars allow for compact and readable descriptions of the syntax of programming languages. Recursion in conventional context-free grammars can in most cases be replaced by iteration. Parser tables of predictive LL-parsers for extended grammars can be generated very efficiently if the length of look-ahead is 1. The generation time is proportional to the size of the parser table, that is the product of grammar size and number of terminal symbols.
02 Dec 1986
TL;DR: The notion of graphic grammars is presented, various programming implementations will be discussed and many motivating examples will be given.
Abstract: Graphics are graphs with attributes at their vertices. Graphic grammars are natural extensions of graph and attribute grammars with rules that are attributed extensions of the “pushout” productions of graph grammars. The notion of graphic grammars is presented and various programming implementations will be discussed. Many motivating examples will be given, including
24 Mar 1986
Journal Article•