Want to build a compiler? These two papers are all you need (2008)

Traditional compiler textbooks are so heavy on theory that it's hard for beginners to actually build a working compiler.

As an alternative, the piece recommends Jack Crenshaw's "Let's Build a Compiler!" series. This tutorial has you implement a simple Pascal compiler with a single-pass structure, combining parsing and code generation while performing only minimal optimization. It was originally written in Pascal, and later C and Forth versions appeared as well. The Forth version in particular is good for learning because it's easy to experiment with interactively.

However, the Crenshaw approach has a limitation: it barely uses internal representations like ASTs. The author attributes this to tree manipulation being inconvenient in Pascal, but argues that high-level languages such as Python, Ruby, Erlang, Haskell, and Lisp can handle such representations easily.

The second key resource is Sarkar, Waddell, and Dybvig's "A Nanopass Framework for Compiler Education." Here, a compiler is viewed not as one giant transformer, but as a chain of many small passes with explicit inputs and outputs. Each pass is kept as simple as possible and coupling is avoided, with a Scheme-based framework verifying the language changes at each stage at runtime.

In conclusion, the advice is to first gain hands-on experience building a compiler yourself, and then, when needed, reinforce the theory with traditional textbooks like the Dragon Book. These two resources alone are enough to gain a practical sense of compiler construction.