go generate pipeliner example

conc_map.go

//go:generate pipeliner map(func(string) string) concurrently as concMap into conc_map.go
func concMap(concurrency int, fn func(string) string, in <-chan string) <-chan string {
	out := make(chan string)
	go func() {
		defer close(out)
		wg := sync.WaitGroup{}
		wg.Add(concurrency)
		for i := 0; i < concurrency; i++ {
			go func() {
				defer wg.Done()
				for item := range in {
					out <- fn(item)
				}
			}()
		}
		wg.Wait()
	}()
	return out
}