Projects sharing features with Acorn

Esprima is a JavaScript parser that converts source code into a structured abstract syntax tree. It implements a specification-driven grammar to ensure compliance with ECMAScript standards, enabling the programmatic analysis and transformation of JavaScript programs. The project provides capabilities for lexical tokenization to break source code into individual symbols and static syntax validation to verify that scripts are well-formed without executing the code. Its functional surface covers JavaScript static analysis, lexical analysis, and the generation of abstract syntax trees.

Babel is a pluggable JavaScript compiler and transpiler that converts modern ECMAScript syntax into backwards-compatible versions of the language. It functions as an abstract syntax tree manipulator, parsing source code into a hierarchical structure to traverse and modify nodes for custom code transformations. The system utilizes a plugin-driven architecture to apply specific transformation rules and supports presets that bundle multiple plugins into named configuration groups. This enables the transformation of experimental syntax and the injection of non-global polyfills to ensure consisten

UglifyJS is a tool for JavaScript code minification, AST manipulation, and source beautification. Its primary purpose is to reduce the file size of JavaScript source code by removing whitespace and shortening variable names to optimize frontend build assets. The project differentiates itself through its ability to programmatically analyze and transform code using abstract syntax trees. It performs constant folding analysis and conditional compilation to eliminate unreachable or redundant code, and it employs a multi-pass compression pipeline to maximize total file size reduction. The tool pr

This project is an AST-based code optimizer and compressor for modern ECMAScript, JSX, and TypeScript source code. It functions as a JavaScript minifier that uses the Babel toolchain to reduce file size by removing unnecessary characters and whitespace while preserving program logic. The tool is distinguished by its ability to process experimental language proposals and transform modern syntax into browser-compatible versions. It provides specialized handling for React JSX transpilation and strips type annotations from TypeScript files to produce compressed production assets. The system cove

UglifyJS2 is a suite of tools designed for parsing, beautifying, mangling, and minifying JavaScript code. It functions by converting source code into an abstract syntax tree to enable programmatic analysis and transformation, and it includes a dedicated generator for creating associated source maps. The project optimizes web production builds by compressing script logic and removing unreachable code. It utilizes name mangling to shorten variable and property names and implements a beautifier to reconstruct compressed scripts into a human-readable layout. The toolset covers broad capability a

This project is a C language interpreter and a practical implementation of a programming language. It parses and executes C source code directly, removing the requirement for a separate compilation step. The interpreter is designed for self-hosting, meaning it is capable of interpreting its own source code to demonstrate recursive language processing and execution. The system covers the primary stages of language processing, including lexical analysis, recursive descent parsing, and tree-walk interpretation using an abstract syntax tree. It manages memory and scope through a dynamic symbol t

JSHint is a JavaScript static analysis tool and linter designed to detect errors and enforce coding standards. It functions as a syntax validator that scans source code to identify potential logic problems and programming mistakes before the code is executed. The tool provides a command line interface for analyzing files and directories. It supports the export of analysis results into standardized formats such as Checkstyle for integration with external build tools. Analysis is managed through a system of linting rule management and environment global configuration. This includes the ability

PHP-Parser is a tool that converts PHP source code into an abstract syntax tree for static analysis and programmatic manipulation. It functions as a parser, a code generator, and a static analysis framework. The project enables the programmatic construction of abstract syntax tree nodes through a fluent interface and provides the ability to transform these trees back into formatted source code. It includes a serializer that exports abstract syntax trees to JSON format and reconstructs them from strings. The toolset covers several capability areas, including namespace resolution, constant exp

Bhai-lang is a TypeScript-based toy programming language and custom syntax interpreter. It functions as an educational language implementation designed to demonstrate core concepts of variable management, conditional logic, and execution flow. The project provides a custom command line interface and an interactive code playground for writing and testing scripts. It serves as a framework for programming language prototyping, allowing for the definition of custom syntax and execution logic. The system covers the full interpreter pipeline, including lexical analysis, recursive descent parsing,

Flow is a JavaScript static type checker and AST parser that identifies type errors and prevents runtime failures through static annotations. It functions as a code intelligence engine and a static analysis linter to identify unsafe coding patterns and enforce consistency across a codebase. The project includes a type annotation stripper that removes static type signatures from source code, ensuring the resulting JavaScript is compatible with any runtime environment. It also provides a parser that converts typed JavaScript into an abstract syntax tree conforming to the ESTree specification.

Otto is a Go implementation of a JavaScript interpreter and embedded scripting engine. It provides a runtime environment for executing JavaScript code within native applications and includes a parser that converts source code into an abstract syntax tree for analysis and processing. The project enables the creation of custom scripting interfaces by binding native Go functions into the JavaScript global scope. It also includes a utility to translate JavaScript regular expression patterns into compatible formats for other programming languages. The engine supports safe script sandboxing throug

This project is a regular expression lexer library and lexical analysis engine used to break input strings into typed token streams. It serves as a foundational component for constructing compilers or interpreters by identifying and categorizing substrings into discrete tokens. The library provides a token stream navigator featuring a cursor-based interface. This allows for sequential traversal of tokenized input and non-destructive lookahead, enabling the inspection of future tokens without advancing the internal position pointer. It includes specific support for recursive descent parsing t

ESTree is a formal schema and set of object interfaces used to represent JavaScript source code as a standardized abstract syntax tree. It serves as a common tree format and parser standard to ensure interoperability between different JavaScript parsers and transformation tools. The specification provides a consistent way to model language constructs, including statements, expressions, and module declarations. It includes detailed representations for modern language features such as classes, private identifiers, and short-circuiting logic like nullish coalescing and optional chaining. The pr

This is an educational tutorial that walks through implementing a complete JSON library from scratch in C. The project covers the full data lifecycle of JSON, including parsing text into structured in-memory representations, validating input against the specification, serializing data back into standard JSON output, and providing structured access to elements within parsed arrays and objects. The implementation is built around a hand-written recursive descent parser that processes JSON text by matching grammar rules to build a structured data tree. Parsed values are stored in a tagged union r

sqlglot is a SQL parser and transpiler that represents queries as abstract syntax trees to enable structural analysis, modification, and semantic transformation. It functions as a dialect translator and query optimizer, converting SQL code between different database engines and simplifying syntax trees through rule-based normalization. The project provides a framework for defining custom SQL dialects by overriding tokenizers, parsers, and generators. It includes a lineage analyzer to track data flow from source tables through complex queries to identify the origin of specific columns. Additi

swift-syntax is a library for parsing, manipulating, and generating Swift source code. It provides a source-accurate abstract syntax tree representation of Swift code, acting as a parser, transformer, and code generator. The project serves as the infrastructure for Swift macro development, enabling the expansion and transformation of source code during compilation. It is used to build compiler tooling for static analysis, formatting, and automated refactoring. The system covers a broad range of source analysis capabilities, including the ability to convert source code into structured trees f

nom is a parser combinator framework for Rust used to build complex parsers by combining small, reusable parsing functions. It functions as a zero-copy parsing tool that minimizes memory overhead by returning slices of the original input instead of allocating new memory. The framework is designed for diverse data formats, serving as a binary data parser with configurable endianness and a bitstream processing library capable of extracting values of arbitrary bit length. It also functions as a streaming data parser that can process data arriving in chunks and signal when additional input is req

YamlDotNet is a YAML serialization library and data mapping tool for .NET. It functions as a parser and generator that converts between .NET objects and YAML formatted text for data storage and configuration. The project provides capabilities for YAML document parsing and data object mapping. It transforms YAML streams into low-level representations or high-level object models for programmatic analysis and converts structured data objects back into valid YAML strings. The library covers general data serialization and configuration file management, allowing application data structures to be m

Pest is a Rust parsing library and automatic parser generator that transforms formal grammar definitions into functional parsers. It specializes in Parsing Expression Grammar to recognize and structure complex text patterns, providing a system for context-free grammar parsing. The library implements zero-copy tokenization and static grammar compilation to reduce runtime overhead. It supports no-std runtime compatibility, allowing the parser to be compiled for embedded or bare-metal environments where a standard library is unavailable. The project covers a range of parsing capabilities, inclu

AST Explorer is a web-based tool for parsing source code into abstract syntax trees and visualizing the resulting tree structure. It serves as a code inspector and transformation playground, allowing users to explore the structural representation of various programming languages through an interactive browser interface. The tool provides a transformation environment where users can apply modification rules to parsed trees to test code modification logic. It features bidirectional mapping that highlights matching tree nodes and source text simultaneously as the cursor moves across the editor.

Nearley is a JavaScript parser toolkit and context-free grammar compiler. It functions as an Earley parser generator that transforms BNF-like grammar definitions into executable code capable of analyzing text and generating abstract syntax trees. The project is distinguished by its ability to handle any context-free grammar, including those with left recursion and ambiguity, by maintaining multiple valid derivations for a single input. It further supports incremental parsing, allowing input strings to be processed in chunks to provide partial results and real-time feedback. Beyond core parsi

Markdig is a high-performance Markdown processor for .NET applications that converts Markdown text into HTML or other target formats. It is a CommonMark compliant parser and extensible engine that can transform Markdown into a searchable and manipulatable abstract syntax tree. The library provides a framework for adding custom syntax and rendering logic through a modular pipeline of parsers and renderers. It supports native ahead-of-time compilation and trimming to minimize binary size. Capabilities include the generation of structured HTML with custom attributes and styling, the extraction

Checkstyle is a Java static analysis tool and linter designed to identify and enforce coding standards and best practices. It functions as a code quality auditor and Javadoc validation tool, checking source code against configurable rulesets to ensure structural and stylistic consistency. The project allows for the creation of custom linting rules by extending a core API to inspect the abstract syntax tree. It further enables specialized validation through the use of XPath expressions to query the syntax tree for specific code patterns and violations. Capability areas include the enforcement

oxc is a high-performance JavaScript toolchain developed in Rust for parsing, transforming, and analyzing JavaScript and TypeScript source code. It provides a set of core utilities including a parser that converts code into an abstract syntax tree, a linter for identifying problematic patterns, a formatter for standardizing visual style, and a minifier for reducing production file sizes. The project focuses on high-performance execution through a system design that utilizes single-pass parsing, zero-copy string slicing, and parallel worker processing to handle large codebases. It further opti

Terser is a JavaScript minifier and compressor designed to reduce file size through whitespace removal, symbol mangling, and logic optimization for ES6+. It functions as a toolkit for minification, a code mangler for shortening variable and property names, and a dead code eliminator that evaluates constant expressions to remove unreachable logic. The project operates as an AST toolkit that parses JavaScript source into SpiderMonkey AST format for structural analysis. It generates source maps to link compressed production code back to the original source, ensuring that minified bundles remain

Emmet is a markup code generator and web development productivity toolkit. It serves as an expansion engine that converts shorthand abbreviations and CSS-like selectors into full HTML, XML, and other markup structures. The project features a dedicated CSS shorthand expansion engine that transforms concise property codes into full style declarations, including the automatic generation of vendor prefixes and gradients. It distinguishes itself by offering a programmable expansion process through custom snippet definitions, abbreviation alias mapping, and script-based extensibility. The toolkit

Participle is a Go parser generator and toolkit for building language frontends. It provides a declarative grammar framework that uses reflection and struct tags to map input patterns directly into typed data structures. The library features a stateful lexical analyzer that employs state machines to handle nested or modal patterns. It includes a lexer code generator to produce optimized code, reducing runtime memory allocations and increasing throughput. The project covers recursive descent parsing with support for union types via sealed interfaces and custom parsing logic through interface-