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

Evaluating expressions

Unicon expressions are goal-directed. When they can, they compute a result, and this is called success. Expressions that have no result are said to fail. Failure will generally prevent a surrounding expression from being performed, and it may trigger backtracking into an earlier part of the expression if there is one that can produce additional results.

This goal-directed evaluation semantics eliminates the need for a Boolean data type, which is usually found in other languages. It also dramatically increases the expressive power of the language, eliminating a lot of tedious checking for sentinel values or writing explicit loops to search for things that can be found by goal-directed evaluation and backtracking. It takes time to get used to this feature, but once mastered, code is shorter and quicker to write.

Forming basic expressions using operators

Many of Unicon's operators will be familiar from other languages, while others are unique. Here...