Attribute Grammar-Based Language Extensions for Java

Abstract

This paper describes the ableJ extensible language framework, a tool that allows one to create new domain-adapted languages by importing domain-specific language extensions into an extensible implementation of Java 1.4. Language extensions may define the syntax, semantic analysis, and optimizations of new language constructs. Java and the language extensions are specified as higher-order attribute grammars. We describe several language extensions and their implementation in the framework. For example, one extension embeds the SQL database query language into Java and statically checks for syntax and type errors in SQL queries. The tool supports the modular specification of composable language extensions so that programmers can import into Java the unique set of extensions that they desire. When extensions follow certain restrictions, they can be composed without requiring any implementation-level knowledge of the language extensions. The tools automatically compose the selected extensions and the Java host language specification.

Polymorphic embedding of dsls

“…The methodology of defining attributes for nodes in the syntax tree has turned out to be particularly useful for generating compilers, but has also been applied for other kinds of language processors [24]. Recently, two systems based on the attribute grammar methodology have been developed independently which allow for extending the Java language with domain-specific extensions [3,30]. Both supply a definition of the Java language based on attribute grammars, into which language extensions can plug their own attribute definitions.…”

“…The former problem can be avoided by restricting the class of grammars, while the latter can only be checked at extension composition time [30]. Compositionality furthermore depends on the language extensions to be restricted to local transformations.…”

Comparison of Context-Free Grammars Based on Parsing Generated Test Data

“…While context-free grammars can always be combined together to form new contextfree grammars, smaller subclasses related to specific parsing technology (or to the requirement of non-ambiguity) usually do not exhibit this property. Several attempts to provide painless language modularity are known, such as Kiama [26] Silver/Copper [28], language boxes methodology [23], etc. Grammar comparisonlike methods may be potentially useful in supporting safe composition.…”

A Role-Based Approach towards Modular Language Engineering

“…In [33] and [34] the authors describe the realisation of a modular Java compiler using a declarative mechanism for extending the attribution of the abstract syntax tree. Single semantic aspects that crosscut the syntactic structure of the AST can be specified in individual modules.…”