bonzini / Smalltalk

GNU Smalltalk is an implementation that closely follows the Smalltalk-80 language as described in the book `Smalltalk-80: the Language and its Implementation' by Adele Goldberg and David Robson.

The Smalltalk programming language is an object oriented programming language. This means, for one thing, that when programming you are thinking of not only the data that an object contains, but also of the operations available on that object. The object's data representation capabilities and the operations available on the object are "inseparable"; the set of things that you can do with an object is defined precisely by the set of operations, which Smalltalk calls "methods", that are available for that object. You cannot even examine the contents of an object from the outside. To an outsider, the object is a black box that has some state and some operations available, but that's all you know.

In the Smalltalk language, everything is an object. This includes numbers, executable procedures (methods), stack frames (called method contexts or block contexts), etc. Each object is an "instance" of a "class". A class can be thought of as a datatype and the set of functions that operate on that datatype. An instance is a particular variable of that datatype. When you want to perform an operation on an object, you send it a "message", and the object performs an operation that corresponds to that message.

Unlike other Smalltalks (including Smalltalk-80), GNU Smalltalk emphasizes Smalltalk's rapid prototyping features rather than the graphical and easy-to-use nature of the programming environment (did you know that the first GUIs ran under Smalltalk?). The availability of a large body of system classes, once you learn them, makes it pretty easy to write complex programs which are usually a task for the so called "scripting languages". Therefore, even though we have a nice GUI environment including a class browser, the goal of the GNU Smalltalk project is currently to produce a complete system to be used to write your scripts in a clear, aesthetically pleasing, and philosophically appealing programming language.

An example of what can be obtained with Smalltalk in this novel way can be found in the manual's class reference. That part of the manual is entirely generated by a Smalltalk program, starting from the source code for the system classes as distributed together with the system.

Oh... of course ;-) GNU Smalltalk has bugs. And of course I like to hear from people who have something to say regarding it. So bug reports, suggestions, help, advices, source code contributions are all welcome. All you have to do is send mail to the GNU Smalltalk mailing list, at [email protected]. Answer is "almost" guaranteed.