Showing papers on "Context-sensitive grammar published in 1982"
04 Oct 1982
TL;DR: In this paper, the authors define grammars on a class of labeled, partially ordered hypergraphs, called distributed systems, and define rewriting rules to model the synchronized evolution of adjacent system components.
Abstract: In the paper we define grammars on a class of labeled, partially ordered hypergraphs, called distributed systems. A distributed system models both the spatial and the temporal aspects of a real system through the relations of adjacency and causality. Terminal symbols represent the (deterministic, certain) past history of the system while nonterminal symbols model the (possibly nondeterministic, potential) future history of the system. The (context free) productions of a grammar represent the possible stand-alone evolutions of system components. From the productions, we obtain a (possibly infinite) number of rewriting rules, which model the synchronized evolution of adjacent system components. The (terminal) distributed systems derived within a given grammar represent the alternative deterministic, concurrent computations of a single nondeterministic system which is thus completely modeled by the grammar.
39 citations
38 citations
04 Oct 1982
36 citations
23 citations
TL;DR: It is shown that the standard construction for converting a pushdown automaton to a context-free grammar is optimal in the sense that it infinitely often produces grammars with the fewest number of nonterminals possible.
21 citations
TL;DR: It is shown that the equivalence problem for LL-regular grammars is decidable by reducing it to the equivalences problem for real-time strict deterministic Grammars.
13 citations
04 Oct 1982
TL;DR: In this article, a graph grammars are used to specify, in a very general way, the evaluators which are generated from atgs, and specify meaningful parsers and compilers if the atgs satisfy some weak conditions.
Abstract: Attribute grammars (atgs, for short) are string rewriting systems, allowing programming languages to be defined together with their context conditions and translations. In this paper graph grammars are used to specify, in a very general way, the evaluators which are generated from atgs. These graph grammars are correct with respect to the languages derived by atgs, and specify meaningful parsers and compilers if the atgs satisfy some weak conditions.
13 citations
TL;DR: The main results are that each context-free language is defined by a grammar G of any desired position-restricted type, and that all languages in L(G1) are defined by an interpretation grammars of G2 of position- restricted type.
12 citations
09 Mar 1982
TL;DR: The concepts of L- and LR-attributed grammar are extended to attributed grammars with an underlying regular right part grammar.
Abstract: The L-attributed grammars form an attractive subclass of attribute grammars since the test for L~attributedness is cheap and attribute evaluation can be done in one left-to-right depth-first traversal of the syntax tree. Still more attractive are subclasses of L-attributed grammars which allow parser-directed attribute evaluation. Two such classes called LL- and LR-attributed grammars, are supported by the compiler generating system MUG 1 (WRC 76, Gan 76). Their implementation is described in the LR~case based on work by Watt (Wat 74,77). The concepts of L- and LR-attributed grammar are extended to attributed grammars with an underlying regular right part grammar.
8 citations
TL;DR: It is proved that a context-free grammar is fairly terminating iff it is non-expansive and that it is fairly generated if it has a grammar all of whose fair derivations are finite.
Abstract: This paper connects between notions of pure formal language theory and nondeterministic programming. The notion of a fair derivation in a context-free grammar is defined, whereby for every variable appearing infinitely often in sentential forms of an infinite derivation, each of its rules is used infinitely often. A context-free language is fairly generated if it has a grammar all of whose fair derivations are finite. It is proved that a context-free grammar is fairly terminating iff it is non-expansive.
5 citations
TL;DR: It is shown that it is possible to transform any LL-regular grammar G into an LL(1) grammar G' in such a way that parsing G' is as good as parsing G.
Abstract: In this paper it is shown that it is possible to transform any LL-regular grammar G into an LL(1) grammar G' in such a way that parsing G' is as good as parsing G. That is, a parse of a sentence of grammar G can be obtained with a simple string homomorphism from the parse of a corresponding sentence of G'. Since any LL(k) grammar is an LL-regular grammar the results that are obtained are valid for LL(k) grammars as well. The relation between LL-regular grammars is expressed by means of a generalized version of the well-known cover relation between two grammars.
TL;DR: A new type of formal grammars where the derivation process is regulated by a certain function which evaluates the words can be regarded as a model for the molecular replication process with selective character.
TL;DR: It is shown that the generative power of k - linear ( k ⩾ 1) grammars is increased by composition, and it is of interest to note that the families of compound linear and compound k -linear languages are equal.
TL;DR: It is proved that the membership problem and the isomorphism problem are recognizable in deterministic polynomial-time.
Abstract: In this paper the complexity of some decision problems for finitely presented abelian groups defined by context-free grammars is investigated. We shall prove that the membership problem and the isomorphism problem are recognizable in deterministic polynomial-time.
TL;DR: Minimal grammar-dependent upper bounds are determined both on the derivational time complexity, that is, the number of derivation steps needed to derive a sentence of given length, and on the derived space complexity, the length of the longest sentential form needed in the derivation.
Abstract: Derivational complexity of context-free grammars is studied. Minimal grammar-dependent upper bounds are determined both on the derivational time complexity, that is, the number of derivation steps needed to derive a sentence of given length, and on the derivational space complexity, that is, the length of the longest sentential form needed in the derivation. In addition to general context-free grammars, these upper bounds are also determined specifically for ɛ -free grammars, non-left-recursive and non-right-recursive grammars, and for LL( k ) grammars. The results might prove useful in parser optimization, because the complexity of a parser is closely related to the derivational complexity of the underlying context-free grammar.
TL;DR: In the literature various proofs of the inclusion of theclass of LL(k) grammars into the class of LR(k), some are correct but the proof is less straightforward than demonstrated here.
TL;DR: A syntax-directed interpreter of attribute Grammars is applied to interpret meta grammars describing translators to help clarify the role of interpreters in the development of knowledge representation.
Abstract: A syntax-directed interpreter of attribute grammars is applied to interpret meta grammars describing translators. A specific example is used which concerns the formal description of the same syntax-directed interpreter of attribute grammars for illustration of our approach.
05 Jul 1982
TL;DR: It is shown that a loop-free tree directed grammar can be transformed into an equivalent top-down tree transducer, and from this fact it follows that given an arbitrary context-free language as input, a treedirected grammar produces an output language which is at most context-sensitive.
Abstract: Tree directed grammars as a special kind of translation grammars are defined. It is shown that a loop-free tree directed grammar can be transformed into an equivalent top-down tree transducer, and from this fact it follows that given an arbitrary context-free language as input, a tree directed grammar produces an output language which is at most context-sensitive.
TL;DR: This paper demonstrates that the metalinguistic formalism of two-level grammars' application to low-level control facilities—labels and goto statements—is not only possible but also reasonably straightforward and manageable.
Abstract: The metalinguistic formalism of two-level grammars (W-grammars) is known to be capable of precisely defining the dynamic semantics of certain features of programming languages in a fairly understandable fashion. This paper demonstrates that its application to low-level control facilities—labels and goto statements—is not only possible but also reasonably straightforward and manageable. Moreover, the extra definitional complexity that arises when there is a mixture of low-level and high-level (if-then-else, while-do, etc.) facilities does not appear to be any worse than it is with other approaches to semantic specification.
TL;DR: It is shown that any two acyclic deterministic pure (dP) grammars that generate the same finite language are isomorphic and that the form-equivalence problem for dP grammar forms is decidable.
TL;DR: It is shown that in a natural subclass of covers, called the class of compatible covers, the method is best possible in the sense that a compatible cover with no null productions can be produced by the method if and only if such a cover exists.