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

Writing a parser for Jzero

The next example is a parser for Jzero, our subset of the Java language. This extends the previous chapter's Jzero example. The big change is the introduction of many context-free grammar rules for more complex syntax constructs than have been seen up to this point. If you wrote a new language not based on an existing one, you would have to come up with the context-free grammar from scratch. For Jzero this is not the case. The grammar we use for Jzero was adapted from a Java dialect named Godiva. To work from a real Java grammar, you can look at https://docs.oracle.com/javase/specs/.

The Jzero lex specification

The Jzero lex specification is as given in the previous chapter, with a one-line package declaration added to the top. The parser must be generated before the scanner is compiled. This is because yacc turns j0gram.y into a parser class whose constant values are referenced from the scanner. Because the static import of yylex() entails using...