itu

itu is a small Go library of iterator utilities.

It provides composable, lazy building blocks for working with Go’s iter package.

Docs: https://pkg.go.dev/github.com/lymar/itu

Goals

• Least surprise: familiar iterator-style utilities for people coming from other ecosystems.
• Lazy by default: values are produced only when the iterator is consumed.
• Streaming-friendly: designed to work well with potentially large or infinite sequences.
• Type-safe: uses Go generics.
• No wrapper types: doesn’t add types like Pair/Tuple/Option; it composes standard iter types.
• Minimal dependencies: built around iter.Seq and related iterator types.

Installation

go get github.com/lymar/itu

Quick example

package main

import (
	"fmt"
	"slices"

	"github.com/lymar/itu"
)

func main() {
	seq := slices.Values([]int{1, 2, 3, 4, 5, 6})

	evens := itu.Filter(seq, func(x int) bool { return x%2 == 0 })
	evensSquared := itu.Map(evens, func(x int) int { return x * x })

	for v := range evensSquared {
		fmt.Println(v) // 4, 16, 36
	}
}

Documentation

API docs are published on pkg.go.dev. Examples live next to the code (see *_test.go with Example... functions).

For local browsing, you can run:

./dev/doc.sh

Then open your browser at: http://localhost:6060/github.com/lymar/itu

License

Licensed under the MIT License. See LICENSE.