rot13 / caesar implementation in go (bad/kinda silly)

rot13.go

package main

import (
	"os"
	"bufio"
	"fmt"
)

// double curly brackets to provide arbitrary scoping for variable shadowing.
// this is rather disgusting, but cleaner than repeat casts or more vars.
func GenCaesar(offset int) (caesarmap map[rune]rune) {{
	offset := rune(offset)
	caesarmap = make(map[rune]rune)

	// Enumerate only up to offset ...
	for i := rune(0); (i + offset) < 26; i++ {
		cur, CUR := 'a' + i, 'A' + i
		caesarmap[cur] = cur + offset
		caesarmap[CUR] = CUR + offset
	}

	// ... and then loop back around
	for i := offset; i < 26; i++ {
		cur, CUR := 'a' + i, 'A' + i
		caesarmap[cur] = cur - offset
		caesarmap[CUR] = CUR - offset
	}

	return
}}

// double curly brackets to provide arbitrary scoping for variable shadowing.
// this is rather disgusting, but cleaner than repeat casts or more vars.
func rot13(in string) (out string) {{
	lookup := GenCaesar(13)

	out := make([]rune, len(in))
	for i, c := range in {
		found := false
		out[i], found = lookup[c]
		if !found {
			out[i] = c
		}
	}

	return string(out)
}}

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	for fmt.Printf("> "); scanner.Scan(); fmt.Printf("> ") {
		in := scanner.Text()
		out := rot13(in)
		fmt.Println(out)
	}

}