Switch hiragana and katakana

package main

import (
"fmt"
)

func main() {
	
	fmt.Println(kanaSwitch("あ ダ  チ  ヂ   ぃ ok い  ぅ hip hip う  ぇ  え  ぉ  お  か "))
}


func kanaSwitch(kana string) (out string) {
	hr := rune('\u3040')
	he := rune('\u3095')
	kr := rune('\u30a0')
	ke := rune('\u30f5')
	diff := int(kr) - int(hr)
		
	runes := []rune(kana)
	for _, k := range runes {
		if int(k) > int(kr) && int(k) <= int(ke)  {
			// is katakana
			out = out + string(rune(int(k)-diff))
		} else if int(k) > int(hr) && int(k) <= int(he) {
			// is hiragana
			out = out + string(rune(int(k)+diff))
		} else {
			out = out + string(k)
		}
	}
	return out
}