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 6: Symbol Tables

To understand the uses of names in program source code, your compiler must look up each use of a name and determine what that name refers to. You can look up symbols at each location they are used by using table data structures that are auxiliary to the syntax tree. These are called symbol tables. Performing operations to construct and then use symbol tables is the first step of semantic analysis. Semantic analysis is where you study the meaning of input source code.

Context-free grammar in the syntax chapters of this book have terminal symbols and non-terminal symbols, and those are represented in tree nodes and token structures. When talking about a program's source code, the word symbol is used differently. In this and later chapters, a symbol refers to the name of a variable, function, class, or package, for example. In this book, the words symbol, name, variable, and identifier are used interchangeably.

This chapter will show you how to construct...