Book Image

Build Your Own Programming Language - Second Edition

By : Clinton L. Jeffery
Book Image

Build Your Own Programming Language - Second Edition

By: Clinton L. Jeffery

Overview of this book

There are many reasons to build a programming language: out of necessity, as a learning exercise, or just for fun. Whatever your reasons, this book gives you the tools to succeed. You’ll build the frontend of a compiler for your language and generate a lexical analyzer and parser using Lex and YACC tools. Then you’ll explore a series of syntax tree traversals before looking at code generation for a bytecode virtual machine or native code. In this edition, a new chapter has been added to assist you in comprehending the nuances and distinctions between preprocessors and transpilers. Code examples have been modernized, expanded, and rigorously tested, and all content has undergone thorough refreshing. You’ll learn to implement code generation techniques using practical examples, including the Unicon Preprocessor and transpiling Jzero code to Unicon. You'll move to domain-specific language features and learn to create them as built-in operators and functions. You’ll also cover garbage collection. Dr. Jeffery’s experiences building the Unicon language are used to add context to the concepts, and relevant examples are provided in both Unicon and Java so that you can follow along in your language of choice. By the end of this book, you'll be able to build and deploy your own domain-specific language.
Table of Contents (27 chapters)
1
Section I: Programming Language Frontends
7
Section II: Syntax Tree Traversals
13
Section III: Code Generation and Runtime Systems
22
Section IV: Appendix
23
Answers
24
Other Books You May Enjoy
25
Index

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 it 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 the...