Regex Tester for Go Developers

package main

import (
    "fmt"
    "regexp"
)

var (
    emailRE = regexp.MustCompile(`^[a-zA-Z0-9._%+\-]+@[a-zA-Z0-9.\-]+\.[a-zA-Z]{2,}$`)
    urlRE   = regexp.MustCompile(`https?://[^\s]+`)
)

func main() {
    // Test a match
    fmt.Println(emailRE.MatchString("user@example.com")) // true

    // Find all URLs in text
    text := "Visit https://example.com or http://test.io"
    urls := urlRE.FindAllString(text, -1)
    fmt.Println(urls)

    // Named groups
    logRE := regexp.MustCompile(`(?P<level>ERROR|INFO) (?P<msg>.+)`)
    m := logRE.FindStringSubmatch("ERROR Something broke")
    fmt.Println(m[1], m[2]) // ERROR Something broke
}