Book Image

Build Your Own Programming Language

By : Clinton L. Jeffery
Book Image

Build Your Own Programming Language

By: Clinton L. Jeffery

Overview of this book

The need for different types of computer languages is growing rapidly and developers prefer creating domain-specific languages for solving specific application domain problems. Building your own programming language has its advantages. It can be your antidote to the ever-increasing size and complexity of software. In this book, you’ll start with implementing the frontend of a compiler for your language, including a lexical analyzer and parser. The book covers a series of traversals of syntax trees, culminating with code generation for a bytecode virtual machine. Moving ahead, you’ll learn how domain-specific language features are often best represented by operators and functions that are built into the language, rather than library functions. We’ll conclude with how to implement garbage collection, including reference counting and mark-and-sweep garbage collection. Throughout the book, Dr. Jeffery weaves in his experience of building the Unicon programming language to give better context to the concepts where relevant examples are provided in both Unicon and Java so that you can follow the code of your choice of either a very high-level language with advanced features, or a mainstream language. By the end of this book, you’ll be able to build and deploy your own domain-specific languages, capable of compiling and running programs.
Table of Contents (25 chapters)
1
Section 1: Programming Language Frontends
7
Section 2: Syntax Tree Traversals
13
Section 3: Code Generation and Runtime Systems
21
Section 4: Appendix

Writing a scanner for Jzero

In this section, we will build a scanner for Jzero, our subset of the Java language. This extends the previous simple2 example to a realistic language size and adds column information, as well as additional lexical attributes for literal constants. The big change is the introduction of many regular expressions for more complex patterns than what we've seen previously. The entire Java language is recognized, but a significant fraction of Java categories cause executions to terminate with an error so that our grammar in the next chapter, along with the rest of the compiler, does not have to consider them.

The Jzero flex specification

Compared to the previous examples, a real programming language lex specification will have a lot more, and more complicated, regular expressions. The following file is called javalex.l and it will be presented in several pieces.

The beginning of javalex.l includes the header and the regular expressions for comments...