Abstract Syntax Tree

An Abstract Syntax Tree (AST) is a tree representation of the abstract syntactic structure of source code written in a programming language. Each node of the tree denotes a construct occurring in the source code, abstracting away details like punctuation and formatting. ASTs are fundamental in compilers, interpreters, and static analysis tools for parsing, transforming, and analyzing code.

Also known as: AST, Syntax Tree, Parse Tree, Abstract Syntax Tree, Syntax Tree Representation

Why learn Abstract Syntax Tree?

Developers should learn about ASTs when working on compilers, linters, code formatters, or tools that require deep code analysis, such as automated refactoring or security scanners. Understanding ASTs enables manipulation of code at a structural level, which is essential for tasks like transpilation (e.g., Babel converting modern JavaScript to older versions) or implementing custom language features.

Learning Resources

• docs: AST Explorer
• tutorial: The Super Tiny Compiler
• book: Crafting Interpreters - Chapter 5: Representing Code
• docs: Abstract Syntax Trees on Wikipedia
• video: ASTs - What are they and how to use them