Showing papers on "Tree-adjoining grammar published in 1976"
TL;DR: A condition for an attribute grammar is given which assures that the semantics of any program can be evaluated in a single pass over the derivation tree, and an algorithm is discussed which decides how many passes from left to right are in general necessary, given the attribute grammar.
Abstract: This paper describes attribute grammars and their use for the definition of programming languages and compilers; a formal definition of attribute grammars and a discussion of some of its important aspects are included. The paper concentrates on the evaluation of semantic attributes in a few passes from left to right over the derivation tree of a program. A condition for an attribute grammar is given which assures that the semantics of any program can be evaluated in a single pass over the derivation tree, and an algorithm is discussed which decides how many passes from left to right are in general necessary, given the attribute grammar. These notions are explained in terms of an example grammar which describes the scope rules of Algol 60. Practical questions, such as the relative efficiency of different evaluation schemes, and the ease of adapting the attribute grammar of a given programming language to the left-to-right evaluation scheme are discussed.
203 citations
01 Jan 1976
TL;DR: Knuth's attribute grammars offer the prospect of automating the implementation of the semantic phase of the translation process by extending ordinary CF grammar to specify the “meaning” of each string in the language.
Abstract: The translation process may be divided into a syntactic phase and a semantic phase. Context-free grammars can be used to describe the set of syntactically correct source texts in a formal yet intuitively appealing way, and many techniques are now known for automatically constructing parsers from given CF grammars. Knuth's attribute grammars offer the prospect of similarly automating the implementation of the semantic phase. An attribute grammar is an ordinary CF grammar extended to specify the “meaning” of each string in the language. Each grammar symbol has an associated set of “attributes:”, and each production rule is provided with corresponding semantic rules expressing the relationships between the attributes of symbols in the production. To find the meaning of a string, first we find its parse tree and then we determine the values of all the attributes of symbols in the tree.
174 citations
TL;DR: This work considers the complexity of the equivalence and containment problems for regular expressions and context-free grammars, concentrating on the relationship between complexity and various language properties.
130 citations
TL;DR: An algorithm for the inference of tree grammars from sample trees is presented, which produces a reduced tree grammar capable of generating all the samples used in the inference process as well as other trees similar in structure.
Abstract: An algorithm for the inference of tree grammars from sample trees is presented. The procedure, which is based on the properties of self-embedding and regularity, produces a reduced tree grammar capable of generating all the samples used in the inference process as well as other trees similar in structure. The characteristics of the algorithm are illustrated by experimental results.
32 citations
TL;DR: The LR(k) concept is generalized to ECFGs, a set of LR-preserving transformations fromECFGs to CFGs is given and finally it is shown how to construct LR-parsers directly from EC FGs.
Abstract: To improve the readability of a grammar it is common to use extended context free grammars (ECFGs) which are context free grammars (CFGs) extended with the repetition operator (*), the alternation operator (¦) and parentheses to express the right hand sides of the productions. The topic treated here is LR-parsing of ECFGs. The LR(k) concept is generalized to ECFGs, a set of LR-preserving transformations from ECFGs to CFGs is given and finally it is shown how to construct LR-parsers directly from ECFGs.
21 citations
01 Jan 1976
TL;DR: The algebraic approach of graph grammars using homomorphisms and pushout constructions given in /Eh-Pf-Sch 73/ and /Ros 74/ is extended to graphic systems which are graphs in a suitable category K including partial graphs, multigraphs, stochastic and topological graphs as discussed by the authors.
Abstract: The algebraic approach, of graph grammars using homomorphisms and pushout constructions given in /Eh-Pf-Sch 73/ and /Ros 74/ is extended to graphic systems which are graphs in a suitable category K including partial graphs, multigraphs, stochastic and topological graphs. These are useful models in computer science, biology, chemistry, network theory and ecology.
13 citations
TL;DR: It is shown that the equivalence problem for linear s-grammars is decidable in polynomial time.
11 citations
TL;DR: In the context independent L systems with varlsus generalizations of context free grammars, the class of ETOL systems (see [S ] ) fGgnls is perhaps the central cl;dss among various classes of context indepenGent L systems.
7 citations
TL;DR: It is shown that one can determine whether a given grammar fits another given grammar, and it is established that the containment problem for Szilard languages is decidable.
Abstract: One of the methods for defining translations is the so called syntax-directed translation scheme which can be interpreted as a pair of rather similar grammars with the productions working in parallel. Because of the similarity of the grammars each of the two grammars “fits” the other in the sense that for each derivation process in one grammar leading to a terminal word the corresponding derivation process in the other grammar also leads to a terminal word. For many practical applications it suffices to consider the case that one of the grammars fits the other, but not necessarily conversely. Investigating this idea, translations are obtained which are more powerful than the syntax-directed. It is shown that one can determine whether a given grammar fits another given grammar. As a by-product, it is established that the containment problem for Szilard languages is decidable.
6 citations
TL;DR: This work defines a mapping from the context-free grammars to the class of one-state pushdown acceptors and finds that every turn-bounded grammar is equivalent to a turn- bounded grammar in Greibach form, a property not shared by the ultralinear Grammars.
Abstract: We define a mapping from the context-free grammars to the class of one-state pushdown acceptors. A turn-bounded grammar is a cfg for which its corresponding one-state pda is finite-turn. From S. Ginsburg and E. H. Spanier it follows that this class of grammars generates the ultralinear languages. Our main result is that every turn-bounded grammar is equivalent to a turn-bounded grammar in Greibach form, a property not shared by the ultralinear grammars. Since Greibach's construction does not preserve turnboundedness an alternate construction is required to obtain our result. As a corollary we have that every Ȩ -free ultralinear language is accepted by a onestate finite-turn pda that reads an input symbol on every move.
6 citations
TL;DR: Variations of programmed grammars, where control is imposed over sets of productions rather than over single productions, are studied, which corresponds to the notion of tables in the theory of L systems.
01 Jan 1976
TL;DR: It is proved that these two generalizations of the notion of a random context grammar do not increase the language generating power of the class of random context grammars.
Abstract: Two generalizations of the notion of a random context grammar are considered. The first one equips a random context grammar with a possibility of a (limited) counting of a number of occurrences of the symbol to be rewritten. The second one applies productions in parallel (as in L systems). It is proved that these two generalizations do not increase the language generating power of the class of random context grammars. Also some normal form theorems are proved.
09 Aug 1976
TL;DR: This paper is concerned with a formal model for data structure definition: data graph grammars (DGG's).
Abstract: This paper is concerned with a formal model for data structure definition: data graph grammars (DGG's).
01 Jan 1976
TL;DR: The close relationship between programming language syntax, context-free grammars (abbreviated cfgs), parsing, and compiling is well-known and is extensively discussed in [1], but many of the problems about programming languages, one might wish to solve, are equivalent to undecidable grammar problems.
Abstract: The close relationship between programming language syntax, context-free grammars (abbreviated cfgs), parsing, and compiling is well-known and is extensively discussed in [1]. Unfortunately, many of the problems about programming languages, one might wish to solve, are equivalent to undecidable grammar problems. Two especially important such problems are (1) the emptiness of intersection problem, i.e. determining if the intersection of the languages generated by a pair of grammars is empty, and (2) the grammar class membership problem, i.e. determining for a fixed class of grammars r and a grammar G, if G is an element of T.
01 Jan 1976
TL;DR: Some formal properties of completion grammars are investigated and a related class of automata is introduced and it is shown that by an extension of the systems, it is possible to deal with weaker precedence relations.
Abstract: Completion grammars are a new class of rewriting systems designed to model case systems. In this paper we investigate some formal properties of these grammars and introduce a related class of automata. Also it will be shown that by an extension of the systems, it is possible to deal with weaker precedence relations. In this context an effectively computable measure for the degree of grammaticality is introduced. The paper concludes with a short discussion on the way in which the grammars are applied. to (natural) language analysis(and synthesis).
TL;DR: It is shown that the families of languages defined by {ie397-04}(G) and {IE397-05}) are equal when G is an ɛ-free context-free grammar form and underlines the usefulness of the notion of grammar forms in formal language theory.
Abstract: A context-free grammar form G defines a family of context-free grammars {ie397-01}(G). In this paper {ie397-02}(G) is extended to give the family of terminal context grammars {ie397-03}(G), which were introduced by Book [4]. It is shown that the families of languages defined by {ie397-04}(G) and {ie397-05}(G) are equal when G is an ?-free context-free grammar form. This generalizes the result of Book [4] for context-free grammars and underlines the usefulness of the notion of grammar forms in formal language theory.
01 Aug 1976
TL;DR: A method is discussed that maps theorem proving using clause interconnectivity graphs onto formal grammars and the languages generated by the grammARS relate to the proofs of the theorems.
Abstract: : A method is discussed that maps theorem proving using clause interconnectivity graphs onto formal grammars. The languages generated by the grammars relate to the proofs of the theorems. (Author)
TL;DR: Generating grammars, recognition automata, and other facilities for the specification of languages are reviewed.
Abstract: Generating grammars, recognition automata, and other facilities for the specification of languages are reviewed.
TL;DR: The “context-free” properties of a state grammar have been used to extend the algebraic parsing technique for languages generated by state grammars, viz., context-sensitive languages.
Abstract: A technique that represents derivations of a context-free grammarG over a semiring and that obtains for a wordw inL(G) the set of all canonical parses forw has previously been described. A state grammar is one of a collection of grammars that place restrictions on the manner of application of context-free-like productions and that generate a noncontext-free language. The “context-free” properties of a state grammar have been used to extend the algebraic parsing technique for languages generated by state grammars,viz., context-sensitive languages. The extension for state grammars is not unlike that required for other types of grammars in whose collection state grammars are representative.