Abstract. This paper describes the Java Language Extender 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 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. 1

. Aspect-oriented programming provides the programmer with means to cross-cut conventional program structures, in particular the class hierarchies of object-oriented programming. This paper studies the use of aspect orientation in structuring syntax directed compilers implemented as attribute grammars. Specifically, it describes a method for specifying definitions of related attributes as `aspects' and treating them as first-class objects, that can be stored, manipulated and combined. It is hoped that this embedding of an aspect-oriented programming style in Haskell provides a stepping stone towards a more general study of the semantics of aspect-oriented programming. 1 Introduction Compilers are often structured by recursion over the abstract syntax of the source language. For each production in the abstract syntax, one defines a function that specifies how a construct is to be translated. The method of structuring compilers in this syntax--directed manner underlies the for...

Attribute grammar specification languages, like many domain specific languages, offer significant advantages to their users, such as high-level declarative constructs and domain-specific analyses. Despite these advantages, attribute grammars are often not adopted to the degree that their proponents envision. One practical obstacle to their adoption is a perceived lack of the both domain-specific and general purpose language features needed to address all of the different aspects of a problem. Here we describe Silver, an extensible attribute grammar specification language, and show how it can be extended with general purpose features such as pattern matching and domain specific features such as collection attributes and constructs for supporting data-flow analysis of imperative programs. Silver is implemented in itself by a Silver attribute grammar and utilizes forwarding to implement the extensions in a cost-effective manner. The result is an attribute grammar specification language with a rich set of language features.

This paper presents a new strict, purely functional implementation of attribute grammars. Incremental evaluation is obtained via standard function memoization. Our new implementation of attribute grammars increases the incremental behaviour of the evaluators by both reducing the memoization overhead and increasing their potential incrementallity. We present also an attribute grammar transformation, which increases the incremental performance of the attribute evaluators after a change that propagates its effects to all parts of the syntax tree. These techniques have been implemented in a purely functional attribute grammar system and the first experimental results are presented.

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This paper introduces generic attribute grammars which provide support for genericity, reusability and modularity in attribute grammars. A generic attribute grammar is a component that is easily reused, composed and understood. Attribute grammar based systems may be constructed out of a set of generic components, that can be analysed and compiled separately. We show how to generate deforestated attribute evaluators for those components. As a result, redundant intermediate data structures used to glue different components are eliminated.

Spreadsheets can be viewed as a highly flexible endusers programming environment which enjoys wide-spread adoption. But spreadsheets lack many of the structured programming concepts of regular programming paradigms. In particular, the lack of data structures in spreadsheets may lead spreadsheet users to cause redundancy, loss, or corruption of data during edit actions. In this paper, we demonstrate how implicit structural properties of spreadsheet data can be exploited to offer edit assistance to spreadsheet users. Our approach is based on the discovery of functional dependencies among data items which allow automatic reconstruction of a relational database schema. From this schema, new formulas and visual objects are embedded into the spreadsheet to offer features for auto-completion, guarded deletion, and controlled insertion. Schema discovery and spreadsheet enhancement are carried out automatically in the background and do not disturb normal user experience. 1.

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