Compilers: Principles, Techniques, and Tools[1] is a computer science textbook by Alfred V. Aho, Monica S. Lam, Ravi Sethi, and Jeffrey D. Ullman about compiler construction for programming languages. First published in 1986, it is widely regarded as the classic definitive compiler technology text.[2] It is known as the Dragon Book to generations of computer scientists[3][4] as its cover depicts a