The source code for this chapter can be found here.
In this chapter, you will begin to write useful software that takes advantage of text entries and text views, to allow the user to enter data within various input fields, and to generate an output from those inputs after clicking a button. In addition, you will also be exposed to the 'html!' macro within the horrorshow crate. You will be writing a program that takes inputs on the left pane, and generates minified HTML within the right text view.
Note that there isn't any external state to worry about in this chapter, as there was in the last. All of the state that we are concerned with is contained within the GTK objects that we will be interacting with.