Demystifying Parsers and ASTs

Table of Contents

1. Introduction
2. Programming Language Architectures
   1. Compiled Programming Languages
   2. Interpreted Programming Languages
   3. Transpiled Programming Languages
   4. Bytecode Interpreted Programming Languages
3. Overview of Building a Programming Language
   1. Parser and AST
   2. Compiler, Interpreter, or Transpiler
4. Understanding Abstract Syntax Trees (AST)
   1. AST Representation of Code
   2. JavaScript Example using Esprima
5. Introducing "My Pio" Programming Language
   1. Purpose and Features
   2. Transpiling to JavaScript
6. Coding the "My Pio" Programming Language

Building a Programming Language: From Parser to Transpiler

Creating a programming language is a complex task that involves various components and processes. In this article, we will explore the different aspects of building a programming language, from understanding the underlying architectures to implementing a basic language. We will delve into the role of the parser and abstract syntax trees (AST), discuss the choices of using a compiler, interpreter, or transpiler, and introduce a simple programming language called "My Pio."

Introduction

Programming languages serve as a means of communication between humans and computers. They provide a set of rules and syntax that allow programmers to express their intentions and solve problems. While many programming languages already exist, there may be a need for creating new ones to cater to specific requirements or improve productivity.

Programming Language Architectures

Before diving into the process of building a programming language, it is essential to understand the different architectures available. Broadly speaking, programming languages can be categorized into four main types: compiled, interpreted, transpiled, and bytecode interpreted.

Compiled Programming Languages

Compiled languages, such as C, C++, and Java, undergo a compilation process where the source code is converted into machine code before execution. This results in faster execution but requires a separate compilation step for different platforms.

Interpreted Programming Languages

Interpreted languages, like Python and JavaScript, do not require a compilation step. Instead, an interpreter reads and executes the code directly. Interpreted languages offer flexibility but may sacrifice speed compared to compiled languages.

Transpiled Programming Languages

Transpiled languages, such as TypeScript, are a hybrid of compiled and interpreted languages. They are source-to-source compiled, meaning the code is first transformed into another language (e.g., JavaScript) before execution. This enables developers to use advanced features while ensuring compatibility across platforms.

Bytecode Interpreted Programming Languages

Bytecode interpreted languages, like Java and C#, compile the source code into an intermediate bytecode, which is then executed by a virtual machine (JVM or CLR). This approach provides a balance between performance and portability.

Overview of Building a Programming Language

To build a programming language, software developers need to tackle multiple components that work together to execute code. Let's take a step-by-step look at the process involved.

Parser and AST

Regardless of the programming language architecture chosen, a crucial component in building a language is the parser. The parser analyzes the syntax of the source code and generates an abstract syntax tree (AST). An AST represents the code structure in a hierarchical manner, enabling further processing and analysis.

To understand the concept of an AST, let's consider JavaScript as an example. The Esprima JavaScript parser is a useful tool for visualizing the AST of JavaScript code. It provides a web page where you can input JavaScript code and view its corresponding AST representation.

Understanding Abstract Syntax Trees (AST)

An AST is a tree-like data structure that represents the underlying code structure. Each node in the tree corresponds to a code element, such as a variable declaration, function call, or expression. The tree structure helps in analyzing, transforming, and executing the code.

Using the Esprima parser example, we can observe how a line of JavaScript code is represented by an AST. The AST for a given code snippet may appear complex but offers a comprehensive representation of the code structure.

Introducing "My Pio" Programming Language

To exemplify the process of building a programming language, we will introduce a simple language called "My Pio." It is designed to demonstrate various language features within a short amount of time and will be transpiled to JavaScript for simplicity.

"My Pio" supports basic arithmetic operations (addition, subtraction, multiplication, and division), variables, while loops, and result printing. This limited feature set allows us to focus on the core concepts of language design and implementation.

Coding the "My Pio" Programming Language

In the next episode, we will dive into coding the "My Pio" programming language. We will start by setting up the development environment and then proceed to implement the language's components, such as the lexer, parser, and interpreter. By the end of the series, you will have a clear understanding of how to approach building a programming language from scratch.

Building a programming language is an exciting journey that requires careful planning, understanding of language architectures, and a systematic implementation approach. Stay tuned for the upcoming episodes as we delve deeper into the fascinating world of language design and implementation.

Highlights:

• Distinction between compiled, interpreted, transpiled, and bytecode interpreted programming languages.
• Importance of the parser and abstract syntax tree (AST) in language development.
• Understanding the structure and representation of an AST using the Esprima JavaScript parser.
• Introduction to the "My Pio" programming language and its features.
• Step-by-step guide to coding the "My Pio" programming language, including lexer, parser, and interpreter.

FAQ: Q: Can I build my own programming language? A: Yes, building your own programming language is possible with the right knowledge and tools. This article provides insights into the process and components involved.

Q: What are the advantages of transpiled programming languages? A: Transpiled languages offer a combination of features from both compiled and interpreted languages. They allow developers to write code using advanced language features while ensuring compatibility across platforms.

Q: How can understanding abstract syntax trees (AST) benefit me as a programmer? A: Understanding ASTs helps programmers analyze, transform, and execute code more effectively. ASTs provide a clear representation of code structure, enabling various code analysis and modification techniques.

Q: Is it necessary to know multiple programming languages to build a new one? A: While it can be helpful to have experience with multiple programming languages, it is not a strict requirement for building a new language. Knowledge of language design principles, algorithms, and data structures is more crucial in this process.