luarrow is a Lua library designed to bring functional programming paradigms into the Lua ecosystem, specifically true pipeline operators and elegant Haskell-style function composition. This library enhances the readability and expressiveness of Lua code by allowing developers to implement functional programming techniques that are typically found in languages like Haskell, OCaml, and Elixir.

Key Features

• True Pipeline Operators: Implement functional pipelines through natural left-to-right flow, utilizing the % and ^ operators. This enables syntax such as x % f ^ g, making function chaining intuitive and easy to read.

• Haskell-inspired Function Composition: The use of * and fun allows for Haskell-like function compositions, letting users write f * g % x instead of the more cumbersome f(g(x)), eliminating the clutter of parentheses.

• Zero Dependencies: luarrow is a pure Lua implementation, ensuring it can be easily integrated into any Lua project without external dependencies.

• Excellent Performance: In LuaJIT environments, pre-composed functions exhibit virtually no overhead compared to traditional Lua constructs, ensuring that performance remains optimal.

Usage Examples

Pipeline Composition

Use the arrow function for pipeline-style processing:

local arrow = require('luarrow').arrow

local _ = 42
  % arrow(function(x) return x - 2 end)
  ^ arrow(function(x) return x * 10 end)
  ^ arrow(function(x) return x + 1 end)
  ^ arrow(print)  -- Outputs: 401

Haskell-style Composition

For a more mathematical approach, the fun function enables right-to-left composition:

local fun = require('luarrow').fun

local function f(x) return x + 1 end
local function g(x) return x * 10 end
local function h(x) return x - 2 end

local result = fun(f) * fun(g) * fun(h) % 42
print(result)  -- Outputs: 401

Real-World Applications

Create data transformation pipelines and streamline list processing:

local fun = require('luarrow').fun

local numbers = {1, 2, 3, 4, 5, 6}

local is_even = function(x) return x % 2 == 0 end
local double = function(x) return x * 2 end

local result = fun(map(double)) * fun(filter(is_even)) % numbers
print(result) -- Outputs: { 4, 8, 12 }

Documentation and Learning Resources

For detailed guidance on the API and practical usage, refer to the API Reference and explore practical examples in the Examples Directory.

luarrow aims to make Lua coding expressive, elegant, and a more enjoyable experience for developers, fostering cleaner and more maintainable code that reads like poetry.