LPA (Activation Code) string is the QR code you scan for provision eSIM to your telephone. The following code parse the string to it's elements based on GSMA standard.

lpa_regex_parsing.go

package main

// go play with my original code: https://go.dev/play/p/dt8WFHM1E8d

import (
	"fmt"
	"regexp"
)

var validLPA = []string{
	`LPA$www1.a.google.com$ABC1`,
	`LPA$www1.a.google.com$ABC1-X$1.1.1$1`,
	`LPA$www1.a.google.com$ABC1$$1`,
	`LPA$www1.a.google.com$ABC1$10000.2.3333333`,
}

const activationCodeRegex = `^((?P<LPA>LPA)\$(?P<FQDN>([a-zA-Z0-9]{1}[a-zA-Z0-9-]{0,62})(\.[a-zA-Z0-9]{1}[a-zA-Z0-9-]{0,62})*?(\.[a-zA-Z]{1}[a-zA-Z0-9]{0,62})\.?)\$(?P<AC_TOKEN>[A-Z0-9-]+)(\$(?P<OID>([0-9]+)(\.[0-9]+)*)?(\$(?P<CONFIRMATION_CODE>1))?)?$)`

var (
	activationCodeRegexp = regexp.MustCompile(activationCodeRegex)
	groupNames           = activationCodeRegexp.SubexpNames()
)

func main() {
	fmt.Printf("groupNames: %+#v\n", groupNames)
	var (
		matches [][]string
		result  []map[string]string
	)
	for _, lpaString := range validLPA {
		matches = activationCodeRegexp.FindAllStringSubmatch(lpaString, -1)
		fmt.Printf("%s - %#+v\n", lpaString, matches)

		var tmpMap = map[string]string{}
		for idx, name := range groupNames {
			if name != "" && idx > 0 {
				tmpMap[name] = matches[0][idx]
			}
		}
		result = append(result, tmpMap)

	}

	fmt.Printf("result: %+#v\n", result)
}