VisualWorks

VisualWorks is a cross-platform implementation of the Smalltalk language. It is implemented as a development system based on "images", which are dynamic collections of software objects, each contained in a system image.

The lineage of VisualWorks goes back to the first Smalltalk-80 implementation by Xerox PARC. In the late 1980s, a group of Smalltalk-80 developers spun off ParcPlace Systems to further develop Smalltalk-80 as a commercial product. The commercial product was initially called ObjectWorks, and then VisualWorks. On August 31, 1999, the VisualWorks product was sold to Cincom. VisualWorks runs under many operating systems, including Windows, Mac OS X, Linux, and several versions of Unix.

VisualWorks has a very active third-party developers community, with a non-commercial version available free. The non-commercial version has all the power and functionality of the commercial version. In both versions, as in all Smalltalks, the user can see all the source code. This includes all the system classes, including the browser and GUI builder.

VisualWorks supports cross-platform development projects, because of its built-in multi-platform features. For example, a GUI application needs to be developed only once, and can then be switched to different widget styles. A VisualWorks application can be run on all supported platforms without any modifications. Only the virtual machine is platform-dependent.

Visualworks allows for very fast application development, as individual methods can be compiled even while the program to be developed is running. Compiling a Smalltalk method typically takes significantly less than a second, while doing the same for a C++ project often takes a minute or more. Also, the various code browsers of Visualworks help the developer to quickly locate a class or method of interest.

Execution performance in terms of CPU time and memory consumption of Smalltalk programs is generally not as good as that of statically typed and binary-compiled languages such as C++, Fortran, Pascal or Ada. See the Language Shootout. The Smalltalk-inherent Garbage Collection makes Smalltalk less than ideal for applications with hard realtime requirements. However, the programmer can take various actions to control when and for how long garbage collection occurs, so under most circumstances garbage collection is not a concern.

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