Chapter 2. Advanced Tcl Features

Now that we know Tcl basics a lot better, it is time to learn some of Tcl's more advanced functionality. This chapter focuses on some aspects of Tcl that will be needed for the chapters that follow throughout the book.

This chapter talks about how Tcl works internally, what we need to be aware of and how we can leverage it to our needs. It introduces in detail how Tcl evaluates code, substitutes variables, and evaluates embedded commands. It also talks about the different types of variables and how they can be used within our code.

We also describe how to work with files in Tcl. This chapter covers how to read and write files, and introduces the concept of channels within Tcl and how different types of channels work. We also show how to copy, rename, and delete files and directories, get information about them, and how to learn about platform-specific issues.

After that, you will see how the Tcl packaging system works and how we can extend it and create reusable...