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

Chapter 4: Parsing

In this chapter, you will learn how to take individual words and punctuation, the lexemes, and group them into larger programming constructs, such as expressions, statements, functions, classes, and packages. This task is called parsing. The code module is called a parser. You will make a parser by specifying syntax rules using grammars, and then using a parser generator tool that takes your language grammar and generates a parser for you. We will also look at writing useful syntax error messages.

This chapter covers the following main topics:

  • Syntax analysis
  • Context-free grammars
  • Using iyacc and BYACC/J
  • Writing a parser for Jzero
  • Improving syntax error messages

We will review the technical requirements for this chapter, and then it will be time to refine your ideas of syntax and syntax analysis.