https://github.com/euanwm/go-functional

go-functional is a library that offers functional programming in Go using generics
https://github.com/euanwm/go-functional

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go-functional is a library that offers functional programming in Go using generics

• Host: GitHub
• URL: https://github.com/euanwm/go-functional
• Owner: euanwm
• License: mit
• Fork: true (BooleanCat/go-functional)
• Created: 2023-08-11T11:57:51.000Z (over 1 year ago)
• Default Branch: main
• Last Pushed: 2023-08-17T09:55:48.000Z (over 1 year ago)
• Last Synced: 2024-04-17T22:04:28.014Z (7 months ago)
• Language: Go
• Homepage:
• Size: 269 KB
• Stars: 0
• Watchers: 0
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • Contributing: CONTRIBUTING.md
  • License: LICENSE
  • Code of conduct: CODE_OF_CONDUCT.md
  • Security: SECURITY.md

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README

        
# Functional Programming in Go

![GitHub release (with filter)](https://img.shields.io/github/v/release/BooleanCat/go-functional?sort=semver&logo=Go&color=%23007D9C) [![Actions Status](https://github.com/BooleanCat/go-functional/workflows/test/badge.svg)](https://github.com/BooleanCat/go-functional/actions) [![Go Reference](https://pkg.go.dev/badge/github.com/BooleanCat/go-functional.svg)](https://pkg.go.dev/github.com/BooleanCat/go-functional) [![Go Report Card](https://goreportcard.com/badge/github.com/BooleanCat/go-functional)](https://goreportcard.com/report/github.com/BooleanCat/go-functional) [![codecov](https://codecov.io/gh/BooleanCat/go-functional/branch/main/graph/badge.svg?token=N2E43RSR14)](https://codecov.io/gh/BooleanCat/go-functional)

A general purpose library offering functional helpers for Golang.

```go

// Find the first 5 prime numbers

primes := iter.Take(iter.Filter(iter.Count(), isPrime), 5).Collect()

reflect.DeepEqual(t, primes, []int{2, 3, 5, 7, 11})

```

_[Read the docs.](https://pkg.go.dev/github.com/BooleanCat/go-functional)_

## Core concepts

This library introduces two core concepts, the `Iterator` and the `Option`.

Using these two concepts this library derives many pre-defined iterators for

use.

### The `Option`

The `Option` is simply a type that represents the presence or absence of a

value. Options behave somewhat like enumerations with two variants:

`Some(value)` and `None`.

### The `Iterator`

```go

type Iterator[T any] interface {

	Next() option.Option[T]

}

```

The `Iterator` is an interface that defines the behaviour of some type that

"yields" values. Each call to `Next()` on an `Iterator` will yield another

value as defined by that specific `Iterator`. For example, the iterator

`iter.Count()` yields 0, 1, 2, 3, etc. and onwards to infinity (or the integer

limit!).

Iterators will yield `Some(value)` for as long as they have values to yield.

Iterators that have exhausted all their values will then always yield `None`.

This library defines many iterators and a few are demonstrated below. For the

entire set simply visit the

[package documentation](https://pkg.go.dev/github.com/BooleanCat/go-functional/iter).

### Iterator showcase

Here are a few trivial example of what's possible using the iterators in this

library.

```go

// All even natural numbers (2, 4, 6, 8...)

isEven := func(n int) bool { return n%2 == 0 }

evens := iter.Filter(iter.Drop(iter.Count(), 1), isEven)

```

```go

// All non-empty lines from a file

lines := iter.Exclude(iter.LinesString(file), filters.IsZero)

```

```go

// String representations of numbers

numbers := iter.Map(iter.Count(), strconv.Itoa)

```