Apple Dylan

Apple Dylan was the implementation of the Dylan programming language, produced by Apple Computer. Apple Dylan was originally developed as the toolbox and application language for the Apple Newton, but later released as a stand-alone development environment for the "classic" Mac OS, only to be abandoned shortly thereafter. Apple Dylan was code-named Leibniz (a pun, of sorts, since Gottfried Leibniz and Isaac Newton are credited as the inventors of calculus).

Development environment

Apple Dylan includes a dynamic, integrated development environment inspired by Smalltalk, Macintosh Common Lisp and Think C. Like Think C—and unlike Smalltalk and Lisp—it draws a clear distinction between the development environment and the program being developed. It accomplishes this by linking code—called a “stub”—into the target program, allowing the IDE to communicate with it (to inject code, perform introspection, etc.) without sharing a runtime environment with the IDE.

The IDE (originally code-named “Hula”) includes:
* "Binder": a tool for configuring browsers
* A source database
* A definition database
* Incremental compilation
* A cross-platform source debugger
* Profiling tools
* An interface builder

The basic browser window in the Apple Dylan environment is Binder. A Binder window consists of a number of linked panes. Each pane has an input, an output, an aspect and a presentation style. A pane's input is the output of another pane—a pane displays information about the selected object(s) in its input pane. Aspects are properties of the input, such as source code, contents, callers, readers, writers, references or compilation warnings. This information can be presented in an outline or a graph. Inputs, aspects and styles could be used to construct replicas of the Smalltalk source browser, or static call graphs, or ad-hoc displays such as the callers of readers of variables that the selected function writes. All views are live: recompiling a function updates any displays that include its who-calls information, for example.

The outline view includes visual indicators that display whether a source record has unsaved changes, has changed since it was last compiled or has compiler-generated messages (warnings and errors).

User interface framework

Apple Dylan includes a user interface framework, written in Dylan by Mike Lockwood. The framework is tightly integrated with a WYSIWYG interface builder code-named Meccano, written by Robin Mair. The interface builder is linked into an application, allowing users to switch between Edit and Run modes while the application is running. “Decorators” are represented as graphical objects that can be dragged onto a user interface object to modify its behavior or appearance via object composition.

Implementation

The core of Apple Dylan is implemented in Macintosh Common Lisp (MCL), upon which the rest is implemented in Dylan. The Apple Cambridge office started life as an acquisition of Coral Software, the developers of Macintosh Common Lisp.

When Dylan was retargeted from the ARM to the desktop, the back end was modified to use APPLEX, a portable assembler designed by Wayne Loufborrow's team in Apple Cupertino.

See also

* Dylan programming language
* History of the Dylan programming language

External links

Related to Apple Dylan
* [http://osteele.com/museum/apple-dylan from Oliver Steele]
* [http://wiki.opendylan.org/wiki/view.dsp?title=Apple%20Dylan from the Dylan Wiki]
* [http://apple.computerhistory.org/discuss/msgReader$186?mode=day "Last day at Apple/End of the Dylan project"]