Syntax-directed Translation Schemes Research Articles

A systematic approach to the implementation of attribute grammars with conventional compiler construction tools

This article describes structure-preserving coding patterns to code arbitrary non-circular attribute grammars as syntax-directed translation schemes for bottom-up and top-down parser generation tools. In these translation schemes, semantic actions are written in terms of a small repertory of primitive attribution operations. By providing alternative implementations for these attribution operations, it is possible to plug in different semantic evaluation strategies in a seamlessly way (e.g., a demand-driven strategy, or a data-driven one). The pattern makes possible the direct implementation of attribute grammar-based specifications with widely-used translation schemedriven tools for the development of both bottom-up (e.g. YACC, BISON, CUP) and top-down (e.g., JavaCC, ANTLR) language translators. As a consequence, initial translation schemes can be successively refined to yield final efficient implementations. Since these implementations still preserve the ability to be extended with new features described at the attribute grammar level, the advantages from the point of view of development and maintenance become apparent.

Translator inversion

In recent years significant efforts have been made in the area of automatic program generation to integrate the technique of translator inversion. The essential idea in using the inversion transformation is that in some problem domains where typically a complicated translator is required, the definition of the inverse description is much easier to manage. Useful applications of the inversion transformation can be found for example in the area of code generation and translation between languages (i.e. both to and from). We have developed an algorithm of translator inversion which capitalizes on the fact that (under given conditions) a translator can be transformed to a syntax directed translation scheme (SDTS) and a collection of predicates (relations) both of which are invertible in themselves. Termination and correctness of the algorithm, and applicability conditions of translators constructed by inversion transformation are also investigated.

Developing integrated environments with ASDL

The authors present the Abstract-Type and Scheme-Definition Language (ASDL), a new formalism and environment kernel. The main goal of this object-oriented kernel is to reconcile integration and extensibility. ASDL adopts the ideas underlying language-based editor generators but overcomes their extensibility deficiencies. ASDL combines an object-oriented type system with syntax-directed translation schemes and a target-language interface. Its power lies in utilizing inheritance for structure-driven computations. The authors discuss object types, translation rules, and semantic information in ASDL.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

On Deterministic Multi-Pass Analysis

Chains (or cascade composition) of push-down transducers are introduced as a model of multi-pass compilers. We focus on deterministic chains, since nondeterministic transducer chains of length two define the recursively enumerable sets. Deterministic chains recognize in linear time a superset of context-free deterministic languages. This family is $\mathcal{CH}$ closed under Boolean operations, disjoint shuffle,and reverse deterministic pushdown translation, but not under homomorphism. Equivalent definitions of the family in terms of composition of syntax-directed translation schemes and control languages are considered. The family is a strict hierarchy ordered by the length of the chain. The complexity of $\mathcal{CH}$ is obviously linear, but not all linear-time parsable languages are in $\mathcal{CH}$. On the other hand it strictly includes the Boolean closure of deterministic languages. Finally $\mathcal{CH}$ is not comparable with another classical Boolean algebra of formal languages, namely real-time languages.

A portable compiler for microcomputers

The implementation of a microprocessor programming language, called MBPL is introduced. The primary requirement for choosing the language implementation method is the compiler portability. To achieve this, an intermediate language and virtual processors are used. The compiler is developed along with the recursive descent method. It is written in MBPL using the bootstrap principle. The compiler generates an object code which has to be interpreted by a virtual processor. The translation process is described by a syntax-directed translation scheme over an extended context-free input grammar.

A language-driven generalized numerical database translator

Numerical databases arise in many scientific applications to keep track of large dense and sparse matrices, residing on secondary devices in matrix compact data representation. This paper describes a language-driven generalized data translator for translating any numerical database from one matrix compact data representation to another. Our approach is to describe any matrix compact data representation by a physical schema and any numerical database and its mapping to storage by data language facilities. The languages are processed by a Generalized Syntax-Directed Translation Scheme (GSDTS) to automatically generate FORTRAN conversion programs which become the major modules of the translator.

Interdependent translation schemes

A translation scheme for specifying translations which depend on both syntactic (input) structure and semantic (output) structure is introduced. Such schemes are called interdependent translation schemes. The syntactic and semantic structures are assumed to be context-free, but their interaction gives rise to a contextual dependence which provides considerably more power than the usual syntax directed translation scheme. It is shown that under two forms of leftmost restriction the class of translations generated by interdependent translation schemes is equal to the class of Turing-computable relations. Length increasing schemes generate translations which are characterized by context-sensitive languages. Interdependent translation schemes which allow associations between nodes in the input and output derivation trees are introduced, and it is shown that these also generate all Turing-computable relations. Normal forms for these schemes are also defined.

Tree transducers, L systems, and two-way machines

A relationship between parallel rewriting systems and two-way machines is investigated. Restrictions on the “copying power” of these devices endow them with rich structuring and give insight into the issues of determinism, parallelism, and copying. Among the parallel rewriting systems considered are the top-down tree transducer; the generalized syntax-directed translation scheme and the ETOL system, and among the two-way machines are the tree-walking automaton, the two-way finite-state transducer, and (generalizations of) the one-way checking stack automaton. The. relationship of these devices to macro grammars is also considered. An effort is made .to provide a systematic survey of a number of existing results.

Embedding semantics in LR parser tables

AbstractThis paper addresses two of the problems commonly associated with LR parsing and syntax directed translation schemes, namely grammar stratification and excessively large table size, A solution is discussed which can eliminate stratification of the grammar by allowing the designer to embed semantics directly within the LR table (i.e., at shift and error entries instead of just at reduce entries) and to use global context to determine what semantics should be performed. The non‐stratified grammar can produce a significantly smaller LR table than the corresponding stratified grammar. The compatibility of this scheme with commonly used table compaction techniques is also discussed.

The ELL(1) parser generator and the error recovery mechanism

A syntactic error recovery technique is presented that is simple and at the same time very powerful. It has the main property that it is phrase marker oriented, where phrase markers are considered symbols delimiting language constructions, e.g., begin and end for blocks, (and) for expressions, and [and] for indices. The basic idea of this error recovery technique originates from P. Branquart and has been worked out in the Algol 68 compiler project, see [8] and [9]. Here, we are especially concerned with the generation aspects of error recovery. In particular, it is investigated how error recovery can be mechanised in an ELL(1) and LALR(1) syntax directed translation scheme and which conditions the syntax must satisfy. Both the ELL(1) and LALR(1) generators are implemented and are part of the system LILA: a Language Implementation LAboratory [28, 29, 30]. Only the ELL(1) generator is described here.

On coupled languages and translations

A class of formal grammars called coupled grammars are introduced. These are formal generative models for languages as well as translations. As language generating devices these are more powerful than context-free grammars and as translation generating devices these arc more powerful than syntax directed translation schemes. Three parameters of these grammars: degree, order and µ-simplicity are identified, which characterize aspects of their description. The structures induced on coupled languages and translations by restrictions placed on the values of these parameters (of coupled grammars), are studied. Some of the specific results are: the degree and order induce infinite proper hierarchies on the classes of coupled languages and translations.

Formal translations and Szilard languages

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.

Are two contex-free languages translatable in a syntax-directed translation scheme?

Syntax Directed Translation Schemes (SDTS's) are a formalism for describing the process of translation within a syntax directed compiler. In this scheme each production of the source context-free grammarG1 is coupled with a production of the object context-free grammarG2.

A note on left-recursive rules and the partitioning of a recognition matrix for syntax-directed translation

Given a context-free grammarG with a cycle of productionsA 1 →A 2 α 1,A 2 →A 3 α 2, ...,A m →A 1 α m, it is shown that there is a grammarG 1 in which the only left-recursive rules are of the formA 1 →A 1 α, andL(G 1)=L(G). Using this normalization it is then shown that a Boolean matrix used in the analysis phase of some syntax-directed translation schemes may be partitioned into rectangular and upper-triangular submatrices.