Open-source alternatives to Expr

The Common Expression Language specification is a formal standard for a non-Turing-complete expression language designed for safe, portable, and fast logic evaluation. It serves as a cross-language logic standard and a declarative policy language, providing a consistent semantic framework for executing boolean expressions and data transformations across different programming environments. This specification acts as an embedded expression engine that allows applications to integrate portable logic for evaluating user-defined configurations. It is specifically designed to enable safe user-defin

This project is a Lisp interpreter implementation guide and framework designed to teach the core principles of programming language design. It provides a structured, step-by-step technical framework for building a functional Lisp language from scratch, featuring a specialized interpreter engine and an S-expression parser that converts syntax into abstract syntax trees. The project emphasizes a code-as-data metaprogramming framework, enabling the implementation of macros, quoting, and quasiquoting to transform expressions during evaluation. It is designed with host language agnosticism, allowi

govaluate is a Go expression evaluator and runtime logic parser. It functions as a dynamic rule engine that converts string-based expressions into executable operations, allowing for the calculation of mathematical and logical expressions at runtime. The library enables the execution of business rules and custom formulas without recompiling source code. It supports extending evaluation behavior through the injection of external parameters and the execution of user-defined custom functions. The system provides capabilities for dynamic data validation, including regular expression matching and

Goja is a JavaScript engine and ECMAScript compliant interpreter implemented entirely in Go. It serves as an embedded scripting engine that allows Go applications to execute JavaScript code and integrate a programmable scripting layer without relying on Cgo or external native dependencies. The project functions as a bridge between Go and JavaScript, enabling bidirectional data exchange and function invocation. It allows Go hosts to expose native structs, slices, and maps as JavaScript objects and arrays, while providing mechanisms to export script values and functions back into native Go type

Scriptable interpreter written in golang

PHP bindings for the Go programming language (Golang)

A Lua VM in Go

A fast script language for Go

Expression evaluation in golang

QLExpress is a dynamic scripting engine and expression language for the Java platform. It functions as a runtime expression evaluator and business rule engine, allowing applications to execute scripts and evaluate business logic without requiring system recompilation. The engine distinguishes itself through a secure scripting sandbox that enforces security policies via class whitelisting and execution timeouts. It supports high-precision mathematics to prevent rounding errors and provides language alias support to create domain-specific languages that resemble natural language. Additional cap

RulesEngine is a business logic evaluator for .NET that executes complex rule workflows and dynamic expressions against input data. It functions as a dynamic expression evaluator and an externalized logic framework, allowing the definition and management of business rules in JSON format to change application behavior without recompiling code. The project decouples decision logic from source code by loading policies from external files or databases. It supports the registration of custom classes and methods to extend standard expression capabilities through type injection. The framework cover

Power-Fx is a declarative logic framework and low-code formula language based on Excel formulas. It functions as an expression parser and evaluator that transforms formula strings into an abstract syntax tree to execute logical operations and resolve values. The project provides a standardized integration layer to connect formula-based logic to external data sources for querying and pushing records. This allows for the definition of business rules and calculations that can be shared as consistent logic across different applications and platforms.

HCL is a configuration language implementation designed for parsing, evaluating, and encoding structured settings through the use of blocks and attributes. It functions as a configuration AST parser and a schema-based decoder that maps attributes and blocks to internal data structures using predefined rules. The project includes an expression evaluation engine that resolves dynamic values and cross-references through multi-phase processing of variables and functions. It also provides a configuration file formatter to standardize the layout and indentation of source code for consistent visual

actionlint is a static analysis tool and linter specifically designed for GitHub Actions workflow files. It functions as a CI workflow validator and YAML configuration linter to ensure the syntax and logic of automation files are correct before deployment. The project distinguishes itself by performing deep security auditing and script analysis. It includes a shell script auditor to detect syntax bugs and script injection vulnerabilities in inline commands, and it scans for hardcoded credentials to prevent security leaks. The tool covers a broad range of validation capabilities, including ex

Aviatorscript is a high-performance scripting language and expression evaluation engine designed for integration within Java applications. It enables the dynamic execution of mathematical and logical formulas by compiling script instructions directly into Java bytecode at runtime. The engine distinguishes itself by transforming dynamic logic into machine-readable instructions, allowing for near-native execution speeds. It includes a built-in caching mechanism that stores compiled bytecode to eliminate redundant parsing and compilation overhead during repeated formula execution. This library

Rhai is an embedded scripting engine and dynamically typed language designed for integration into Rust applications. It functions as an abstract syntax tree compiler and native interop layer, allowing developers to map Rust types and functions into a scripting environment for bidirectional communication. The project serves as a framework for creating customizable domain-specific languages. It allows for the definition of custom operators, syntax, and restricted execution environments, enabling the creation of specialized languages with tailored functional sets. The engine covers a broad rang

Oils is a Unix shell interpreter and scripting language runtime that combines a modern shell language with POSIX and Bash compatibility. It functions as a structured data shell, integrating JSON and J8 formats to manage complex data without relying on string parsing. The system is distinguished by a C++ transpiled interpreter that converts a subset of Python source code into strongly typed C++ for high-performance execution. It features a garbage-collected typed runtime that supports prototype-based polymorphism, lexical closures, and reference-based variable mutation. To decouple shell logic

Flecs is a high-performance entity component system framework and data-oriented programming library. It serves as a simulation engine core and game engine architecture tool, decoupling state from behavior by separating entities, components, and systems. The framework features a runtime reflection layer for dynamic data inspection and a built-in scripting system for defining entity behavior without recompilation. It also includes a network interface and REST API for remote simulation administration and state querying. The library covers a broad surface of simulation capabilities, including ar

Wasmer is a high-performance runtime engine designed to execute sandboxed WebAssembly modules across server-side, edge, and browser environments. It functions as a comprehensive platform for building, distributing, and running isolated applications, providing a secure and portable execution layer that maintains consistency across diverse hardware architectures and operating systems. The platform distinguishes itself through a robust toolchain that enables cross-language interoperability and the transformation of code into portable binary packages. It supports ahead-of-time binary generation t

Gorilla is a foundational infrastructure framework for large language model function calling. It provides a system for training, evaluating, and executing the translation of natural language instructions into accurate API calls and executable code. The project integrates a structured API documentation index, a fine-tuning pipeline for model adaptation, and a secure sandboxed action runtime for executing model-generated commands. The framework distinguishes itself through a specialized evaluation benchmark suite that measures the accuracy, cost, and latency of function calls. It includes tools

Boa is a high-performance JavaScript engine and parser designed to execute JavaScript code and analyze source code structure. It functions as a runtime environment for executing scripts to automate tasks or process data, providing both a command-line JavaScript interpreter and a tool for converting source code into abstract syntax trees. The engine is capable of compiling to WebAssembly, allowing the runtime to be deployed and executed within web browser environments. It includes an interactive read-eval-print loop for real-time logic testing and snippet execution via a terminal. The system

Scriban is a text templating library and .NET scripting engine used for dynamic text generation. It functions as a template processor and a safe scripting sandbox, providing a secure execution environment that restricts object exposure to prevent unauthorized code execution. The project also includes an abstract syntax tree template parser that allows for programmatic template analysis and modification. The engine features a dedicated Liquid template engine and compatibility mode, allowing it to parse, execute, and convert templates written in Liquid syntax. It distinguishes itself through a

Alice is a PHP test data generator and fixture library used to automate the creation of large sets of fake objects and entities. It functions as an object hydrator and random data provider, allowing users to define the structure and attributes of dummy test data in markup or arrays to simulate specific application states. The library distinguishes itself through a template-based system that supports fixture inheritance to reduce data duplication. It utilizes a flexible instantiation model that allows for custom factory integration, method invocation, and property hydration via reflection or c

This project is a POSIX shell toolset providing utilities for parsing, formatting, interpreting, and validating shell scripts. It includes a parser that converts Bash and Zsh source code into structured syntax trees, a formatter for standardizing script layout, and a runtime interpreter for executing shell commands and script logic. The toolset supports dialect-aware parsing to handle multiple shell language specifications. It provides capabilities for static analysis, allowing shell source code to be converted into structured data for external manipulation or validation against specific dial

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

Go bindings for Lua C API - in progress

Starlark in Go: the Starlark configuration language, implemented in Go