// Package version provides machinery for versioning file names// with a timestamp-based version stringpackage version import (	"path"	"regexp"	"strings"	"time") const versionFormat = "-v2006-01-02-150405.000" var versionRegexp = regexp.MustCompile(`-v\d{4}-\d{2}-\d{2}-\d{6}-\d{3}`) // Split fileName into base and extension so that base + ext == fileNamefunc splitExt(fileName string) (base, ext string) {	ext = path.Ext(fileName)	base = fileName[:len(fileName)-len(ext)]	// .file splits to base == "", ext == ".file"	// so swap ext and base in this case	if ext != "" && base == "" {		base, ext = ext, base	}	return base, ext} // Add returns fileName modified to include t as the versionfunc Add(fileName string, t time.Time) string {	base, ext := splitExt(fileName)	s := t.Format(versionFormat)	// Replace the '.' with a '-'	s = strings.ReplaceAll(s, ".", "-")	return base + s + ext} // Remove returns a modified fileName without the version string and the time it represented// If the fileName did not have a version then time.Time{} is returned along with an unmodified fileNamefunc Remove(fileName string) (t time.Time, fileNameWithoutVersion string) {	fileNameWithoutVersion = fileName	base, ext := splitExt(fileName)	if len(base) < len(versionFormat) {		return	}	versionStart := len(base) - len(versionFormat)	// Check it ends in -xxx	if base[len(base)-4] != '-' {		return	}	// Replace with .xxx for parsing	base = base[:len(base)-4] + "." + base[len(base)-3:]	newT, err := time.Parse(versionFormat, base[versionStart:])	if err != nil {		return	}	return newT, base[:versionStart] + ext} // Match returns true if the fileName has a version stringfunc Match(fileName string) bool {	return versionRegexp.MatchString(fileName)}