An Abstract Syntax Tree (AST) is a data structure used to represent the structure of source content in a hierarchical, tree-like form.
Each node in the tree corresponds to a meaningful element of the content, such as an expression, statement, or directive, rather than the raw text itself. This abstraction allows for easier manipulation, analysis, and transformation of the content during processes like parsing or compiling.
The AST strips away superficial syntax details and focuses on the underlying logical structure of the code or document.
Unlike a flat text representation, an AST is structured around Semantic Elements rather than specific syntax. For example, rather than storing the exact parentheses used in an expression, the AST might store a node representing a Function Call or Mathematical Operation.
This structure enables tools such as Compilers, Interpreters, and Static Analyzers to reason about the content in a more meaningful way. Since the tree can be navigated recursively, it becomes a powerful framework for applying transformations or generating new representations of the original content.
ASTs are commonly used in a wide range of applications, from programming languages and markup parsers to document converters and visualization tools. They provide a bridge between raw text and executable or interpretable meaning.
Tools like Pandoc, for instance, use an AST to convert documents between formats by mapping content into a neutral intermediate structure. This approach makes it easier to support multiple output formats, custom filters, and Syntax-Aware Transformations without hardcoding specific rules for each case.
# See
- ⇒ AST ⇒ Virtual Machine