Penlight
A collection of pure Lua libraries for data handling, functional programming, and OS path management, inspired by Python's standard library.
What is Penlight?
Penlight is a collection of pure Lua libraries that extend Lua's standard library with utilities for data handling, functional programming, and OS path management. It solves the problem of Lua's minimal standard library by providing Python-inspired modules for common tasks like reading config files, manipulating strings and tables, and managing filesystem paths. This makes Lua more practical for application development and scripting.
Lua developers and scripters who need enhanced standard library functionality for building applications, tools, or scripts, particularly those familiar with Python's conveniences.
Developers choose Penlight because it offers a comprehensive, Python-inspired toolkit within pure Lua, reducing the need to write boilerplate code or rely on multiple disparate libraries. Its focus on compatibility across Lua versions and pure Lua implementation (for core modules) ensures portability and ease of integration.
Overview
A set of pure Lua libraries focusing on input data handling (such as reading configuration files), functional programming (such as map, reduce, placeholder expressions,etc), and OS path management. Much of the functionality is inspired by the Python standard libraries.
Use Cases
Best For
- Extending Lua's standard library with Python-like utilities
- Reading and parsing configuration files in Lua applications
- Implementing functional programming patterns in Lua scripts
- Managing filesystem paths and operations cross-platform
- Manipulating strings and tables with advanced operations
- Building command-line tools with argument parsing support
Not Ideal For
- High-performance real-time applications where minimal Lua overhead and native C speed are critical
- Embedded systems with strict memory constraints that cannot tolerate additional library footprint
- Projects already integrated with game engines like Löve2D that provide their own utility libraries
- Environments requiring zero external dependencies beyond stock Lua for core file operations
Pros & Cons
Pros
Supports reading Unix config and Windows INI files via the config module, plus tabular data management with 2D array operations, filling gaps in Lua's standard library for application development.
Includes map, reduce, lambda expressions, and list comprehensions through modules like func and comprehension, enabling Python-like coding styles directly in Lua for reduced boilerplate.
Provides cross-platform tools for file and directory operations, such as copying, moving, and path queries via the path and dir modules, enhancing portability without OS-specific code.
Offers advanced string manipulation like lexical scanning and text wrapping, plus specialized table types like List and Map, extending Lua's built-in capabilities for complex data tasks.
Cons
File and directory functions require LuaFileSystem, and dir.copyfile on Windows needs Alien, adding installation complexity and breaking the pure Lua promise for some operations.
While LuaRocks simplifies setup, manual installation involves copying directories and managing module paths, which can be error-prone compared to integrated package managers in other ecosystems.
As a pure Lua library with extensive features, it may introduce performance overhead in resource-constrained environments, especially for operations that could be optimized with C extensions.
Frequently Asked Questions
Related Projects
Lua FunLua Fun is a high-performance functional programming library for Lua designed with LuaJIT's trace compiler in mind.
MosesUtility library for functional programming in Lua
RxLuaReactive Extensions for Lua
lua-stdlibGeneral Lua libraries
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