GNU Smalltalk

FAQs - Free Smalltalk Environments

GNU Smalltalk is a free implementation of the Smalltalk-80 language. It runs on most versions on Unix, as well as under Windows. Smalltalk is a dynamic object-oriented language, well-versed to scripting tasks.
GNU Smalltalk implements the recognized ANSI standard for the Smalltalk language, which is ultimately a descendant of the Smalltalk-80 language developed at Xerox PARC. Much of the class library is identical to that of Smalltalk-80: they both have objects, classes, single inheritance, blocks, garbage collections, collections, streams, and many other bits. In addition to this, GNU Smalltalk provides other classes including networking and GUI programming.

How stable is GNU Smalltalk? How scalable? How fast?

It is quite stable. There are bugs for sure in the virtual machine, but unless you're unlucky you shouldn't be affected. This is especially true for the stable branch, where only changes to improve stability are made; development releases are by their very nature less stable.
It is quite scalable, even though the garbage collector performs worse once you have more than 150-200 MB of live data. Very long strings also do not perform as well as they could. In general, object-orientation makes it easier to pick good data structures (such as streams).
It is quite fast. While GNU Smalltalk has an experimental just-in-time compiler, even the bytecode interpreter should be faster than most other scripting languages. However, GNU Smalltalk's base classes are written entirely in Smalltalk (unlike Python or Lua, for example). While this gives more flexibility to the programmer, programs that heavily use dictionaries may run slower than the equivalent programs in other languages.

Does copyright restrict the use of GNU Smalltalk?

It does, but in general you don't need to worry much about the licensing of your Smalltalk programs. The class library is licensed under the GNU LGPL. Thus, it permits using the library together with non-free programs. The virtual machine and the bindings to external libraries are licensed under the GNU GPL, with a special exception that allows Smalltalk programs to be linked with the functions exported by the virtual machine and said bindings.

Where's the GUI?

GNU Smalltalk does not by default start a full-blown integrated development environment. However, one is available and can be started with this command:

gst -qK browser/Run.st