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

Building internal nodes from production rules

In this section, we will learn how to construct the tree, one node at a time, during parsing. The internal nodes of your syntax tree, all the way back up to the root, are built from the bottom up, following the sequence of reduce operations with which production rules are recognized during the parse. The tree nodes used during the construction are accessed from the value stack.

Accessing tree nodes on the value stack

For every production rule in the grammar, there is a chance to execute some code called a semantic action when that production rule is used during a parse. As you saw in Chapter 4, Parsing, in the Putting together the yacc context-free grammar section, semantic action code comes at the end of a grammar rule, before the semicolon or vertical bar that ends a rule and starts the next one.

You can put any code you want in a semantic action. For us, the main purpose of a semantic action is to build a syntax tree node. Use...