gistfile1.go

package main

import (
	"fmt"
)

type T interface{}
type S interface{}
type U interface{}

func chzip(ch1 chan T, ch2 chan S, foo func(t T, s S) U) chan U {
	var u = make(chan U)

	go func() {
		var v1 T
		var v2 S
		var ok1, ok2 bool
		for {
			select {
			case v1, ok1 = <-ch1:
				if !ok1 {
					close(u)
					return
				}
				v2, ok2 = <-ch2
				if !ok2 {
					close(u)
					return
				}
			case v2, ok2 = <-ch2:
				if !ok2 {
					close(u)
					return
				}
				v1, ok1 = <-ch1
				if !ok1 {
					close(u)
					return
				}
			}
			u <- foo(v1, v2)
		}

	}()
	return u
}

func main() {
	ch1 := make(chan int)
	ch2 := make(chan int)

	adder := func(a, b int) int { return a + b }

	ch3 := chzip(ch1, ch2, adder)

	fmt.Println("hello interface")
}

gistfile2.txt

prog.go:54: cannot use ch1 (type chan int) as type chan T in function argument
prog.go:54: cannot use ch2 (type chan int) as type chan S in function argument
prog.go:54: cannot use adder (type func(int, int) int) as type func(T, S) U in function argument
 [process exited with non-zero status]