Go lang implementation of python's range function

gistfile1.txt

// https://docs.python.org/3/library/functions.html#func-range
package main

import (
	"fmt"
)

type Range struct {
	Step  int32
	Max   int32
	Start int32
}

type void struct{}

func NewRangeMore(start, max, step int32) Range {
	return Range{Step: step, Max: max, Start: start}
}

func NewRange(max int32) Range {
	return NewRangeMore(1, max, 1)
}

func (r Range) For(looper func(i int32)) {
	if r.Step == 0 {
		panic("Step cannot be zero")
	}
	if r.Start > 0 && r.Max < 0 && r.Step < 0 && r.Start > r.Max {
		for i := r.Start; i > r.Max; i = i + r.Step {
			looper(i)
		}
	} else if r.Step > 0 && r.Max > 0 && r.Start > 0 && r.Start <= r.Max {
		for i := r.Start; i < r.Max; i = i + r.Step {
			looper(i)
		}
	} else {
		panic("bad")
	}
}

func main() {
	r := NewRangeMore(5, -1, -1)
	fmt.Printf("%#v\n", r)
	r.For(func(i int32) {
		fmt.Printf("\tlooping at i %d\n", i)
	})

	s := NewRange(3)
	fmt.Printf("%#v\n", s)
	s.For(func(i int32) {
		fmt.Printf("\tlooping at i %d\n", i)
	})

	h := NewRange(-1)
	fmt.Printf("%#v\n", h)
	h.For(func(i int32) {
		fmt.Printf("\tlooping at i %d\n", i)
	})
}