Extensible algebraic datatypes with defaults

Zenger, Matthias; Odersky, Martin

doi:10.1145/507635.507665

Cited by 49 publications

(28 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Another well-known challenge in programming language design is to simultaneously support both the easy addition of new types and the easy addition of new operations to an existing type hierarchy [Reynolds 1975;Cook 1991;Odersky and Wadler 1997;Krishnamurthi et al 1998;Findler and Flatt 1999;Garrigue 2000;Zenger and Odersky 2001]. For example, suppose we have a program with a collection of types representing various shapes-like Shape, Rectangle, and Triangle-and a collection of operations on these types, like area and intersect.…”

Section: The Binary Methods Problemmentioning

confidence: 99%

MultiJava

Clifton

Millstein

Leavens

et al. 2006

ACM Trans. Program. Lang. Syst.

View full text Add to dashboard Cite

MultiJava is a conservative extension of the Java programming language that adds symmetric multiple dispatch and open classes. Among other benefits, multiple dispatch provides a solution to the binary method problem. Open classes provide a solution to the extensibility problem of object-oriented programming languages, allowing the modular addition of both new types and new operations to an existing type hierarchy. This article illustrates and motivates the design of MultiJava and describes its modular static typechecking and modular compilation strategies. Although MultiJava extends Java, the key ideas of the language design are applicable to other object-oriented languages, such as C# and C++, and even, with some modifications, to functional languages such as ML.This article also discusses the variety of application domains in which MultiJava has been successfully used by others, including pervasive computing, graphical user interfaces, and compilers. C. Clifton et al.MultiJava allows users to express desired programming idioms in a way that is declarative and supports static typechecking, in contrast to the tedious and type-unsafe workarounds required in Java. MultiJava also provides opportunities for new kinds of extensibility that are not easily available in Java.

show abstract

Section: The Binary Methods Problemmentioning

confidence: 99%

MultiJava

Clifton

Millstein

Leavens

et al. 2006

ACM Trans. Program. Lang. Syst.

View full text Add to dashboard Cite

show abstract

“…JaCo JaCo is an extensible compiler for Java 1.4 written in a slightly extended Java dialect called Keris that supports extensible algebraic data types with defaults [jac07b,ZO01a]. Keris is itself implemented as a modular language extension to JaCo.…”

Section: Compilers Overviewmentioning

confidence: 99%

“…The first implementation of JaCo was done in a Java dialect supporting algebraic types with defaults [ZO01a]. A set of object-oriented architectural patterns was used to further support extensibility.…”

Section: Related Workmentioning

confidence: 99%

The jastadd extensible java compiler

EkmanTorbjörn

HedinGörel

2007

SIGPLAN Not.

View full text Add to dashboard Cite

The JastAdd Extensible Java Compiler is a high quality Java compiler that is easy to extend in order to build static analysis tools for Java, and to extend Java with new language constructs. It is built modularly, with a Java 1.4 compiler that is extended to a Java 5 compiler. Example applications that are built as extensions include an alternative backend that generates Jimple, an extension of Java with AspectJ constructs, and the implementation of a pluggable type system for nonnull checking and inference.The system is implemented using JastAdd, a declarative Java-like language. We describe the compiler architecture, the major design ideas for building and extending the compiler, in particular, for dealing with complex extensions that affect name and type analysis. Our extensible compiler compares very favorably concerning quality, speed and size with other extensible Java compiler frameworks. It also compares favorably in quality and size compared with traditional nonextensible Java compilers, and it runs within a factor of three compared to javac.

show abstract

“…to add a new method to existing classes) in object-oriented programming languages, and the "visitor pattern" [4] is invented for this very purpose. The fact that it is difficult to add both new data constructors and new operations without modifying existing code is called the expression problem (aka the extensibility problem) and has been extensively studied (e.g., [3,32,22]). The problem, though symmetrical, seems to have severer impact on polymorphic variant calculi than on polymorphic record calculi, simply because functions are harder to define than constructors.…”

Section: A Problem Of Polymorphic Variant Calculimentioning

confidence: 99%

Polymorphic variants in Haskell

Kagawa

2006

Proceedings of the 2006 ACM SIGPLAN Workshop on Haskell

View full text Add to dashboard Cite

In languages that support polymorphic variants, a single variant value can be passed to many contexts that accept different sets of constructors. Polymorphic variants can be used in order to introduce extensible algebraic datatypes into functional programming languages and are potentially useful for application domains such as interpreters, graphical user interface (GUI) libraries and database interfaces, where the number of necessary constructors cannot be determined in advance. Very few functional languages, however, have a mechanism to extend existing datatypes by adding new constructors. In general, for polymorphic variants to be useful, we would need some mechanisms to reuse existing functions and extend them for new constructors.Actually, the type system of Haskell, when extended with parametric type classes (or multi-parameter type classes with functional dependencies), has enough power not only to mimic polymorphic variants but also to extend existing functions for new constructors. This paper, first, explains how to do this in Haskell's type system (Haskell 98 with popular extensions). However, this encoding of polymorphic variants is difficult to use in practice. This is because it is quite tedious for programmers to write mimic codes by hand and because the problem of ambiguous overloading resolution would embarrass programmers. Therefore, the paper proposes an extension of Haskell's type classes that supports polymorphic variants directly. It has a novel form of instance declarations where records and variants are handled symmetrically.This type system can produce vanilla Haskell codes as a result of type inference. Therefore it behaves as a preprocessor which translates the extended language into plain Haskell. Programmers would be able to use polymorphic variants without worrying nasty problems such as ambiguities.

show abstract

Extensible algebraic datatypes with defaults

Cited by 49 publications

References 11 publications

MultiJava

MultiJava

The jastadd extensible java compiler

Polymorphic variants in Haskell

Contact Info

Product

Resources

About