We identify three design principles for reflection and metaprogramming facilities in object oriented programming languages. Encapsulation: meta-level facilities must encapsulate their implementation. Stratification: meta-level facilities must be separated from base-level functionality. Ontological correspondence: the ontology of meta-level facilities should correspond to the ontology of the language they manipulate. Traditional/mainstream reflective architectures do not follow these precepts. In contrast, reflective APIs built around the concept of mirrors are characterized by adherence to these three principles. Consequently, mirror-based architectures have significant advantages with respect to distribution, deployment and general purpose metaprogramming.

We present GJ, a design that extends the Java programming language with generic types and methods. These are both explained and implemented by translation into the unextended language. The translation closely mimics the way generics are emulated by programmers: it erases all type parameters, maps type variables to their bounds, and inserts casts where needed. Some subtleties of the translation are caused by the handling of overriding.GJ increases expressiveness and safety: code utilizing generic libraries is no longer buried under a plethora of casts, and the corresponding casts inserted by the translation are guaranteed to not fail.GJ is designed to be fully backwards compatible with the current Java language, which simplifies the transition from non-generic to generic programming. In particular, one can retrofit existing library classes with generic interfaces without changing their code.An implementation of GJ has been written in GJ, and is freely available on the web.

Class loaders are a powerful mechanism for dynamically loading software components on the Java platform. They are unusual in supporting all of the following features: laziness, type-safe linkage, user-defined extensibility, and multiple communicating namespaces.We present the notion of class loaders and demonstrate some of their interesting uses. In addition, we discuss how to maintain type safety in the presence of user-defined dynamic class loading.

article Free Access Share on Strongtalk: typechecking Smalltalk in a production environment Authors: Gilad Bracha View Profile , David Griswold View Profile Authors Info & Claims ACM SIGPLAN NoticesVolume 28Issue 10Oct. 1, 1993 pp 215–230https://doi.org/10.1145/167962.165893Online:01 October 1993Publication History 167citation673DownloadsMetricsTotal Citations167Total Downloads673Last 12 Months25Last 6 weeks13 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteeReaderPDF

Abstract GCI is a Unix‐based tool for developing interactive CAD programs. By separating command/ menu definitions from the progam, GCI makes it easier to change and extend the user interface. The language provided by GCI is used to define the syntax of commands, menus, messages, and help text. Generally, GCI supports a static hierarchical structure of commands and menus. However, through a program interface, an application program has the freedom to change environments, commands and menus. This flexibility of run‐time control of the user interface is essential for developing highly responsive interfaces in a CAD environment. This paper presents the main concepts and definition language of GCI. It then discusses architectural and implementation issues, and finally presents a typical application's view of using the tool.