This note is on the intro. and lexical parts.
Since I studied my compiler course pretty well (I think), the first 2 chapters look some familiar. Well yea, the backend is always the hotspot of modern compiler design. Sb. said to me years ago, that after Knuth invented his grammar analysis algorithm (I forgot the name when I typing this..), the front end research was finalized. maybe, who knows..
First component of a compiler, lexical parser, elaborated in chapter 3, consists of a complete automata. In this chapter, the regex is the input of a lexical analyzer, then a syntax tree is formed, and a DFA will derives from this tree – this step sounds quite innovative to me. then the optimization algo. on a NFA is introduced – grouping the “important” nodes in a NFA.