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

Highlighting errors using parse results

In a BuffEditableTextList component, the fire() method is called whenever the content is changed, as well as whenever the cursor moves. When content is changed, it sets a flag named doReparse indicating that the code should be syntax-checked. The check does not occur until the cursor is moved. The code for the fire() method is shown here:

   method fire(type, param)
      self$Connectable.fire(type, param)
      if type === CONTENT_CHANGED_EVENT then
         doReparse := 1
      if type === CURSOR_MOVED_EVENT &
           old_cursor_y ~= cursor_y then
         ReparseCode()
   end

In the preceding code, the ReparseCode() method is occasionally called in the Unicon IDE in...