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

Assigning type information to declared variables

Type information is constructed during a tree traversal and then stored with its associated variables in the symbol table. This would usually be part of the traversal that populates the symbol table, as presented in the previous chapter. In this section, we will be traversing the syntax tree looking for variable declarations, as we did previously, but this time, we need to propagate type information by using synthesized and/or inherited attributes.

For type information to be available at the time that we are inserting variables into the symbol table, the type information must be computed at some prior point in time. This type information is computed either by a preceding tree traversal or during parsing when the syntax tree is constructed. Consider the following grammar rule and semantic action from Chapter 5, Building Syntax Trees:

FieldDecl: Type VarDecls ';' {
  $$=j0.node("FieldDecl",1030,$1,...