What's New in the Fourth Edition

The fourth edition is up-to-date with Tcl/Tk 8.4, which adds many new features. Tcl has a new Virtual File System (VFS) feature that lets you transparently embed a file system in your application, or make remote resources such as FTP and Web sites visible through the regular file system interface. Chapter 22 is a new chapter on Tclkit and Starkits that use the Metakit embedded database to store scripts and other files. The VFS makes these files appear in a private file system. Starkits provide a new way to package and deploy Tcl/Tk applications. Chapter 21 is a new chapter on using the multi-threading support in Tcl. This is very useful when embedding Tcl in threaded server applications. There are a number of new Tk features, including three new widgets. The spinbox (i.e., combobox) is like an entry widget with a drop-down selection box. The labeled frame provides a new way to decorate frames. The panedwindow is a specialized geometry manager that provides a new way to organize your user interfaces.