Go iterators using Elixir pipe operator.

README.md

To try this code, you can use the modified Go toolchain found at https://github.com/DeedleFake/go/tree/pipe-operator.

go.mod

module test

go 1.22

test.go

package main

import (
	"fmt"
)

type Seq[T any] func(func(T) bool)

func Generate() Seq[int] {
	return func(yield func(int) bool) {
		for i := 0; ; i++ {
			if !yield(i) {
				return
			}
		}
	}
}

func Limit[T any](s Seq[T], n int) Seq[T] {
	return func(yield func(T) bool) {
		s(func(v T) bool {
			if n <= 0 {
				return false
			}
			n--
			return yield(v)
		})
	}
}

func Filter[T any](s Seq[T], f func(T) bool) Seq[T] {
	return func(yield func(T) bool) {
		s(func(v T) bool {
			if f(v) {
				return yield(v)
			}
			return true
		})
	}
}

func Map[T1, T2 any](s Seq[T1], f func(T1) T2) Seq[T2] {
	return func(yield func(T2) bool) {
		s(func(v T1) bool { return yield(f(v)) })
	}
}

func Collect[T any](s Seq[T]) []T {
	var r []T
	s(func(v T) bool {
		r = append(r, v)
		return true
	})
	return r
}

func main() {
	s := Generate() |>
		Filter(func(v int) bool { return v%2 != 0 }) |>
		Map(func(v int) int { return v*2 }) |>
		Limit(10) |>
		Collect()
	fmt.Println(s)
}