I am trying to start on Project 01 but unless I am overlooking something in the reading I do not know where to edit the supplied HDL files to create a chip implementation. Am I overlooking something key in Appendix A or in Chapter 1? Where is the external text editor mentioned in the hardware simulator tutorial ppt slide 11?
Creating a good text editor is hard. It's even harder if it's for programming. Also many people have their preferences (https://en.wikipedia.org/wiki/Editor_war), so my guess is, that it was deemed a relatively minor inconvenience by the authors.
Another way to look at it is this: you're creating a 1980s-era computer. Might as well see how the programmers worked before the IDEs.