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

Avoiding reparsing the entire file on every change

The lexical and syntax analysis necessary to parse input and detect and report syntax errors presented in this book from Chapter 2, Programming Language Design, to Chapter 8, Checking Types on Arrays, Method Calls, and Structure Accesses, are substantial algorithms. Although the Flex and Yacc tools we've used are high-performance, if given a large input file, scanning and parsing become slow enough that users will not want to reparse the whole file each time a user modifies the file in an IDE text editor. In testing, we found that reparsing the entire file became a problem on files larger than 1,000 lines.

Sophisticated incremental parsing algorithms that minimize the amount that must be reparsed after changes are the subject of Ph.D. dissertations and research articles. For the Unicon IDE, a simple approach is taken. Whenever the cursor moves away from a line that has been changed, a parsing unit is selected, starting with...