VisualWorks is one of the leading implementations of the Smalltalk programming language and environment. Smalltalk is an object-oriented, dynamically typed, reflective programming language. ...

VisualWorks lineage goes back to the first Smalltalk-80 implementation by Xerox PARC. In late 80s, a group of Smalltalk-80 developers spun off ParcPlace Systems to further develop Smalltalk-80 as a commercial product. Smalltalk-80 was later renamed as ObjectWorks, and then as VisualWorks. On August 31, 1999, the VisualWorks product was sold to Cincom. VisualWorks runs on many platforms such as Windows, Mac OS X, Linux, and several Unix versions. VisualWorks is in very active development; you can download it here. Bold text // Headline text Link title This article is about the computer research center. ... Microsoft Windows is a family of operating systems by Microsoft. ... Mac OS X (official IPA pronunciation: ) is a line of proprietary, graphical operating systems developed, marketed, and sold by Apple Computer, the latest of which is pre-loaded on all currently shipping Macintosh computers. ... Linux (also known as GNU/Linux) is a Unix-like computer operating system. ... Unix or UNIX is a computer operating system originally developed in the 1960s and 1970s by a group of AT&T employees at Bell Labs including Ken Thompson, Dennis Ritchie, and Douglas McIlroy. ...

VisualWorks excels in cross-platform development projects, because of its built-in multi-plaform 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. GUI can refer to the following: GUI is short for graphical user interface, a term used to describe a type of interface in computing. ...

Subdirectories

All components of the VisualWorks system are installed in a directory named after the version number of the installed system. For instance, vw7.4nc. This directory contains several subdirectories including: bin, doc, examples and many others. In computing, a directory, catalog, or folder, is an entity in a file system which contains a group of files and other directories. ... Software versioning is the process of assigning either unique version names or unique version numbers to unique states of computer software. ... Look up Bin on Wiktionary, the free dictionary Bin can refer to: Any container for storing any kind of material or items, usually with a large opening at the top so that contents can easily be removed, often with a lid. ...

File-in format

File-in format is the original Smalltalk format for representing Classes as text files. These can be "filed in" to the VisualWorks IDEdevelopment environment to generate any classes not already contained in the Smalltalk image. Every file-in document provides a simple textual representation of a Smalltalk class, or classes, in a text file with a .st suffix. It is still supported in VisualWorks, but has been superceded by a Parcels mechanism. There are examples in file-in format in the examples subdirectory. Smalltalk is an object-oriented, dynamically typed, reflective programming language. ... Class may refer to: Appliance classes, in the electric appliance manufacturing industry. ... See Integrated Development Environment (IDE) Integrated_development_environment Binomial name Leuciscus idus Linnaeus, 1758 The ide or orfe, Leuciscus idus, is a freshwater fish of the family Cyprinidae found across northern Europe and Asia. ...

Parcels

Parcels are external file representations of packages.

An Examples Browser is provided as a parcel in the examples directory. Several image level switches are available to specify parcel loading on image startup, see reference [1] for details. The parcel path is the list of directories where VisualWorks looks for parcels. This can be set using the System Settings tool.

Parcels provide the component technology for VisualWorks. Packages and bundles (1)organize the code, (2) model the contents of parcels. Parcels are created by publishing packages/bundles. The term components, in the VisualWorks sphere , is used to refer to parcels, packages, and bundles when it is not necessary to be specific.

The parcel code's organization on loading is determined by its creation. It it was created by publishing a package, it is loaded into the same package. If it was created from a bundle then it can be reloaded as the bundle or as one package.

The load sequence for a package is: 1. Any prerequisite components are loaded. 2. Any defined pre-load action is performed (e.g. undeclared variables initialized) 3. Objects in the package are installed. 4. Every class in the parcel is sent message postLoad: thePackage, and any action executed.

The Parcel Manager

The Parcel Manager is used to load and unload all parcels on the parcel path. A Suggestions view lists Categories containing key add-in parcels-by selecting a category, you get a list of recommended parcels. For example, the UI Painter is located in the Essentials category. There is also a Directory-tree view of the parcel path, for finding parcels outside the Suggestions view. A Loaded view lists all parcels already in the image. Only loaded parcels can be browsed.

A supported VisualWorks product parcel is represented by an icon that looks like a parcel. Parcels from other vendors look like a shopping sack. Because of the convoluted history of Smalltalk class development this can be very useful. For instance, a parcel icon indicates that the Arbor hypertext system is now VisualWorks supported.

You can also load and unload parcels programmatically from your application.

Packages

When a parcel is loaded it is organized as a package, or bundle of packages. When looking for code loaded from a parcel, you can locate the bundle or package with the same name in the System Browser. Packages are categories that organize classes into related groups, according to component. Packages can be grouped into bundles. Packages and bundles can be saved (published) as parcels.

Loading Code Libraries

The initial visual.im image contains minimal development facilities, using basic class libraries. Additional class libraries are provided by VisualWorks or third-party vendors, usually as parcel files. For most non-Smalltalk development environments, code libraries are imported at compile time, using an include command. In Smalltalk, code libraries are loaded into the running system, and become part of the environment. For example, the UI Painteris loaded as a parcel. This page is a candidate to be moved to Wiktionary. ... Smalltalk is an object-oriented, dynamically typed, reflective programming language. ...

The VisualWorks Launcher

The VisualWorks Launcher, usually just called the Launcher, is the control centre for the VisualWorks system. It's the launching pad for all the major tools.

Browsing and Editing Smalltalk Code

In traditional object-oriented programming environments you directly edit a plain text source code file containing class and method definitions. In VisualWorks, like all Smalltalks, everything is an executing object, including classes. In browsing Small classes you are gleaning definitions from executing objects. The main browser/editor in VisualWorks is the System Browser. It allows you to browse classes either in the overall class hierarchy or through their packages. You launch it from the VisualWorks Launcher. This article is becoming very long. ... Source code (commonly just source or code) is any series of statements written in some human-readable computer programming language. ... Class may refer to: Appliance classes, in the electric appliance manufacturing industry. ... method (from Greek methodos, met hodos literally way across). The word entered English in 1541 via French and Latin. ...

List panes in the System Browser allow you to navigate to class and method definitions. You can then view or edit them in a code view, or supplement them with new definitions.

Undeclared Variables

When a variable is deleted while references to it still exist, or loaded via a parcel but never declared, its name enters the Undeclared name space. Undeclared variables can cause certain program errors.

References

[1] VisualWorks® Application Developer's Guide P46-0101-11, available free in the doc directory of the vw7.4nc download.