Golang Generics Acyclic Function Graph

acyclic_generic.go

package main

import (
	"fmt"
)

// Data that flows through the processing pipeline
type Data[T any] struct {
	Type  string
	Path  string
	Value T
}

// The Handler function processes the data and then
// call the handlers downstream from itself
// Each downstream function gets its own copy of the data
type Handler[T any] func(Data[T]) error

type Node[T any] struct {
	Name string
}

func (n *Node[T]) Chain(h ...Handler[T]) Handler[T] {
	return func(d Data[T]) error {
		downstreamHandlers := h

		d.Path = d.Path + fmt.Sprintf("-> (%s, %v)", n.Name, d.Value)

		for _, f := range downstreamHandlers {
			if f == nil {
				fmt.Println(d.Path)
				return nil
			}
			if err := f(d); err != nil {
				return err
			}
		}
		return nil
	}
}

func main() {
	a := Node[string]{"A"}
	b := Node[string]{"B"}
	c := Node[string]{"C"}
	d := Node[string]{"D"}
	e := Node[string]{"E"}
	f := Node[string]{"F"}

	path1 := b.Chain(c.Chain(nil))
	path2 := d.Chain(d.Chain(e.Chain(nil)))
	path3 := f.Chain(path1, path2)

	tree := a.Chain(path1, path2, path3)

	tree(Data[string]{Value: "hello"})
}