Go: Convert CamelCase strings to snake_case, with golang

snake_case.go

// Go Playground: https://play.golang.org/p/RwyPCkRi1S

package main

import (
	"fmt"
	"regexp"
	"strings"
)

var exp = regexp.MustCompile("([a-z0-9])([A-Z0-9])")

func toSnakeCase(s string) string {
	return strings.ToLower(exp.ReplaceAllString(s, "${1}_${2}"))
}

func main() {
	// examples for "normal" strings
	fmt.Println(toSnakeCase("CamelCase"))
	fmt.Println(toSnakeCase("ExampleNumber2"))
	fmt.Println(toSnakeCase("My3rdProject"))

	// examples that perhaps don't work as expected
	fmt.Println(toSnakeCase("UPPERCase"))
	fmt.Println(toSnakeCase("GO2"))
	fmt.Println(toSnakeCase("A2B"))
}

// camel_case
// example_number_2
// my_3rd_project
// uppercase
// go2
// a2_b