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

Establishing the groundwork for symbol tables

In software engineering, you must go through requirements analysis and design before you start coding. Similarly, to build symbol tables, you need to understand what they are for, and how to go about writing the syntax tree traversals that do the work. For starters, you should review what kinds of information your compiler must store and recall different kinds of variables. The information will be stored in symbol tables from declarations in the program code, so let's take a look at those.

Declarations and scopes

The meaning of a computer program boils down to the meaning of the information being computed, and the actual computations to be performed. Symbol tables are all about the first part: defining what information the program is manipulating. We will begin by identifying what names are being used, what they are referring to, and how they are being used.

Consider a simple assignment statement such as the following:

...