Open-source alternatives to Purescript

Cats is a Scala functional programming library and type class library designed to implement algebraic patterns and functional abstractions. It provides a standardized set of interfaces and a modular toolkit of functional wrappers and containers to enable ad-hoc polymorphism and generic programming across disparate types. The project serves as a functional abstraction standard, offering a monad transformer suite to compose nested effectful contexts and handle multiple computational side effects within a single pipeline. It further enables the construction of embedded domain-specific languages

Carp is a statically typed Lisp compiler that compiles Lisp-like syntax directly to C source code, enabling seamless integration with existing C libraries and low-level system programming. It manages memory deterministically at compile time using ownership tracking and linear types, eliminating garbage collection pauses and runtime overhead while ensuring type safety through an inferred static type system. The language distinguishes itself through compile-time macro expansion and metaprogramming capabilities, allowing code generation and transformation before final binary output. It enforces

Reason is a statically typed programming language and compiler based on the OCaml ecosystem. It translates high-level, type-safe source code into either JavaScript or OCaml output, providing a typed alternative for web and system development. The language focuses on providing rigorous type safety and a robust module system while integrating with the JavaScript ecosystem. It allows for the development of applications that leverage existing JavaScript libraries while utilizing a more rigid type system to eliminate common runtime crashes and data mismatches. The project covers capabilities incl

language-ext is a functional programming framework for C# that provides a suite of immutable data structures and monadic types. It enables the implementation of pure functional programming patterns, utilizing containers to manage side effects, optional values, and error handling. The library is distinguished by its advanced concurrency and state management tools, including a software transactional memory system and lock-free atomic references. It also provides specialized utilities for distributed systems, such as vector clocks for causality tracking and deterministic data conflict resolution

Dhall is a type-safe configuration language designed to create programmable configuration files that are guaranteed to terminate. It is a non-Turing-complete language that uses a strict type system to ensure correctness and prevent infinite loops during evaluation. The project functions as a deterministic configuration engine and marshalling tool, converting programmable expressions into static formats such as JSON, YAML, and Bash. It distinguishes itself through a focus on security and integrity, using semantic hashing to pin remote imports and enforcing origin policies to prevent data exfil

This project is a comprehensive collection of reference materials, including a language cheatsheet, a standard library reference, and a concurrency reference. It serves as a guide to modern C++ development, focusing on language syntax, standard library utilities, and template metaprogramming patterns. The repository provides specific guidance on template metaprogramming through a dedicated guide covering compile-time evaluation, type deduction, and variadic template execution. The materials cover a broad range of capabilities, including asynchronous programming, memory management, and system

This project is a comprehensive functional programming curriculum and learning resource for Haskell. It provides sequenced educational paths and technical reference guides designed to take developers from beginner to advanced levels of proficiency. The project distinguishes itself through a deep focus on theoretical and technical foundations, offering detailed studies on type theory, category theory, and runtime internals. It includes a dedicated performance handbook for optimizing execution speed and memory management, as well as an ecosystem guide for managing development tools and editor c

This project is an interactive programming education resource and tutorial designed for learning the Rust programming language and systems programming concepts. It provides a collection of runnable and editable code examples that serve as a practical reference for language syntax and implementation. The resource features an interactive code sandbox that allows users to execute and test code snippets in real time. It emphasizes the verification of technical accuracy by executing embedded code blocks during the build process to ensure all examples remain functional. The content covers a compre

This project is a comprehensive educational resource and programming course covering C++ language semantics and features from C++03 through C++26. It provides structured tutorials and technical guides focused on modern C++ development. The material offers specialized instruction on template metaprogramming, including the use of type traits and compile-time computations. It features detailed guides on concurrency and parallelism for multi-core execution, as well as a reference for software design applying SOLID principles and RAII. Additionally, it covers build performance optimization to redu

The Rust Programming Language Book is the official technical guide and educational resource for the Rust language. It provides a comprehensive walkthrough of the language's design, focusing on its core identity as a systems programming language that enforces memory safety and high-performance execution without the need for a garbage collector. The project is distinguished by its focus on ownership, borrowing, and lifetime tracking, which allow the compiler to verify memory safety and thread safety at compile time. It covers the language's unique approach to zero-cost abstractions, including t

ReScript is a statically typed programming language and compiler designed to transform type-safe source code into efficient, human-readable JavaScript. It functions as a transpiler that enforces data consistency and prevents runtime errors through static type analysis for both web and server applications. The project distinguishes itself as an incremental build system that analyzes dependency graphs to recompile only modified files and their dependents. It includes a JSX compatible compiler for building user interfaces and provides a framework for bridging type-safe code with existing JavaScr

Returns is a functional programming library for Python that provides type-safe containers for managing state, error handling, and optionality. It serves as a monadic container library and a type-safe error handling framework, replacing traditional try-catch blocks and null checks with Result and Optional containers to treat exceptions as data. The project is distinguished by its use of a specialized Mypy static analysis plugin to validate functional pipelines and emulate higher kinded types. It provides mechanisms for isolating side effects through IO containers and offers a framework for typ

c3c is the compiler for the C3 programming language, transforming source code into executable binaries, static libraries, or dynamic libraries using an LLVM backend. It implements a system based on result-based error handling, scoped memory pooling, and a semantic macro system. The compiler provides first-class support for hardware-backed SIMD vectors that map directly to processor instructions and enables runtime polymorphism through interface-based dynamic dispatch. The project covers a broad set of low-level capabilities, including manual and pooled memory management, inline assembly inte

CppGuide is a curated collection of educational resources and practical guides focused on C++ server development, Linux kernel internals, concurrent programming, network protocols, and security exploitation. It provides structured learning paths for backend developers, covering everything from interview preparation to building high-performance network servers and understanding operating system fundamentals. The guide distinguishes itself by offering in-depth, hands-on tutorials that walk through real-world implementations, including building a Redis-like server from scratch, designing custom

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

Binaryen is a WebAssembly compiler toolchain and optimizer designed to transform, validate, and shrink binary modules. It provides a comprehensive intermediate representation framework that converts binary code into a single-assignment form to enable advanced program analysis and code transformation. The project includes a specialized transformation engine that applies iterative optimization passes to increase execution speed and reduce binary size. Additionally, it functions as a transpiler that translates WebAssembly binary modules into executable JavaScript for environments that lack nativ

Crystal is a statically typed, compiled programming language designed for high performance and memory safety. It leverages an LLVM-based compiler to translate source code into optimized machine-executable binaries, while its type-inference-based static analysis enforces strict safety rules during the build process. The language distinguishes itself through a fiber-based concurrent runtime that manages lightweight execution units for asynchronous input and output without blocking the main process. It also features a powerful compile-time macro system that allows for the inspection and transfor

This project is a comprehensive guide and educational resource for the TypeScript language. It covers the fundamental principles of the language, including its structural type system, static type analysis, and the process of transpiling typed source files into JavaScript. The material details how to model complex data and reusable type logic using generics, conditional types, and mapped types. It also explains the use of declaration files to provide type safety for external JavaScript libraries and the integration of type checking into existing JavaScript projects via JSDoc annotations. The

Sway is a smart contract development language and programming environment designed for writing, compiling, and deploying secure blockchain programs. It serves as a type-safe language for building on-chain logic and a static analysis toolchain that validates contracts before they are executed on a network. The ecosystem provides a development environment focused on blockchain application logic and web3 backend engineering. It integrates a type-safe programming approach to reduce vulnerabilities and ensure reliable state transitions for decentralized services. The toolchain incorporates static

Odin is a compiled, statically typed systems programming language designed for high-performance software development. It focuses on pragmatic low-level memory control, providing a toolset for manual memory management and precise control over hardware utilization. The language is distinguished by its flexible memory model, which includes custom allocators and precise data layout capabilities to optimize resource usage. It features a comprehensive foreign function interface for importing assembly files and linking with external libraries using configurable calling conventions. The type system

Scalaz is a functional programming library for Scala that provides a collection of purely functional data structures and type classes. It functions as a framework for organizing functional behaviors into hierarchies to enable generic programming and type-safe transformations. The library includes tools for composing and managing nested functional effects within a single type stack through a monad transformer system. It provides data structures for representing and combining input, output, and optionality effects. The project covers a broad surface of functional abstractions, including the im

Borgo is a statically typed language and compiler that transforms high-level syntax into Go source code. It functions as a transpiler designed to leverage the Go runtime while introducing a type system centered on algebraic data types and result-based error handling. The language distinguishes itself by replacing Go's multiple return values with result and option types, using a dedicated operator for concise error propagation. It implements sum types with exhaustive pattern matching and provides a tool to generate bindings for existing Go packages, automatically converting multi-value returns

Dollar is a functional programming library for Swift that provides a comprehensive toolkit for collection manipulation, string processing, mathematical calculations, and date and time management. It serves as a utility suite for filtering, aggregating, and restructuring arrays and dictionaries. The project implements functional programming patterns such as currying, memoization, and function composition. It also features a chainable wrapper interface that allows multiple data transformations to be applied sequentially before extracting a final result. The library covers a wide range of capab

Coconut is a functional programming language that compiles to Python. It functions as a source-to-source compiler, translating high-level functional syntax into compatible Python code to maintain runtime compatibility. The language introduces a logic system for pattern matching and destructuring complex data structures. It provides a mechanism for tail call optimization to prevent stack overflow errors during deep recursive function calls and employs a lazy evaluation engine to defer computations until results are explicitly required. The project includes support for algebraic data types, pi

This project is a functional programming library and toolkit for building production TypeScript applications. It provides a system for managing concurrency, error handling, and resource lifecycles using functional effects. The project distinguishes itself through a comprehensive suite of specialized toolkits, including a dependency injection framework for decoupling service implementations, a workflow orchestrator for coordinating durable processes, and a SQL database toolkit for consistent data operations across multiple dialects. It also implements an OpenTelemetry instrumentation library f