Comment by Silhouette | Hacker News Reader

Comment by Silhouette | Hacker News Reader

Parent Full thread

My problem with the Dragon Book is more fundamental: having once made a real effort to read it, almost cover to cover, I came away with a few hours less of my life remaining and some ideas about lexers and parsers and the like, but I still had absolutely no idea how to sit down and write a compiler. I don't understand why anyone thinks this is a good book.

There are introductory texts that might not cover the same amount of theory, but at least get you from nowhere to being able to write a basic compiler from start to finish. If you do want some serious theory, particularly on optimizations, then Muchnick blows the Dragon Book away. If you want to work with different kinds of programming language, notably functional programming with a lambda calculus foundation, then these ideas barely appear in the Dragon Book and again there are specialised texts that would serve you much better. What is the target audience for the Dragon Book actually meant to be?

The Dragon Book is supposed to be read by people taking a CS course on compilers, to fill in the gaps. I too don't believe it's a standalone work.

I found Appel's _Modern Compiler Implementation in ML_ to be better-suited to self study, and more modern. I've used OCaml but not SML, and didn't have any problem following it.

This is a wonderful book!

Well, when I wrote a compiler (on a team of 3) the dragon book (first edition) was very helpful, from lexers, parsers, to code generation. So we read it cover to cover (except for Jeanne, who got her PhD from Ullman and who wrote the LALR parser) and used it profusely.

As noted elsewhere in this thread, I think that, in contrast to the OPs article, everyone should read it or Hollub's excellent work that followed the Dragon book by a number of years.

So I would disagree with your opinion about this being a good book, but then I may have the advantage of having spent substantially more time with it.

Jack Crenshaw's book Let's Build a Compiler http://compilers.iecc.com/crenshaw/ is probably too far to the pragmatic end; it essentially walks you through the process of writing a recursive-descent compiler in Pascal for a Pascal-like language that generates code for the m68k. No separate parser and lexer as such, but he does teach you how to turn those kinds of ideas (regexes and EBNF equations) into code more-or-less directly in your head. In short, it was just about perfect for someone who wanted to whip up a nice little compiler for a foogol on a late-1980s DOS box without paying for or finding any tools beyond Turbo Pascal.

It's entirely possible to use the techniques in the book to, say, whip up a compiler in Ruby that turns an inconvenient data format into JSON. The real utility of doing this by hand in 2010 is, however, debatable.

Reply on news.ycombinator.com