[regexp feature request] Support 'Ş' character on word boundary search, like in .NET/Python3/Java regex engine.

[caner-cetin]

What version of Go are you using (go version)?

$ go version

go version go1.20.1 linux/amd64

Does this issue reproduce with the latest release?

Yeaps.

What operating system and processor architecture are you using (go env)?

go env Output

$ go env
GOARCH="amd64"
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOVERSION="go1.20.1"

What did you do?

package main
import(
    fmt
    regexp
)
func DeleteNonDate(toBeDeleted string) (string, string, error) {
	nonDateRegex, err := regexp.Compile(`(?mi)\b(\d{1,2}\s)?(Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec|[Oo]cak|January|February|March|April|May|June|July|August|September|October|November|December|[Şş]ubat|[Mm]art|[Nn]isan|[Mm]ayıs|[Hh]aziran|[Tt]emmuz|[Aa]ğustos|[Ee]ylül|[Ee]kim|[Kk]asım|[Aa]ralık)(\s\d{1,2},?)?(\s\d{4})?\b`)
	if err != nil {
		return "", "", err
	}
	// if no line matches:
	return strings.TrimSpace(nonDateRegex.FindString(toBeDeleted)), nonDateRegex.ReplaceAllString(toBeDeleted, ""), nil
}

func main() {
      excepted, _, err := DeleteNonDate(`asdasd \n \n Şubat 2023 Haziran 2023`)
     if err  != nil {
        panic(err)
      }
      fmt.Println(excepted)
}

What did you expect to see?

Şubat 2023

What did you see instead?

Haziran 2023, missed Şubat 2023 match entirely.

https://regex101.com/r/uq8ZR9/1, live demo to play around. Python, Java, .NET engine supports 'Ş' match with same regex, can we please have it on RE2?

[caner-cetin]

Please hit me up if more edge cases or test cases needed.

[seankhliao]

This should be raised with https://github.com/google/re2

[junyer]

Just to be clear, the Go regexp package¹ and RE2² support \b for ASCII word boundaries only; since that's very unlikely to change in the foreseeable future, you might want to look into using https://github.com/dlclark/regexp2 instead.

Footnotes

1. The Go regexp package is not RE2. ↩

2. RE2 is not the Go regexp package. ↩