获取字符集字符串的编码器/解码器

Is there a function built-in or in a supported package to get a *golang.org/x/text/encoding.Encoder (Decoder) based on an input charset string such as ISO-8859-1 or ISO-8859-15? Right now the only way I see to do it is to match it myself:

func getEncoderForCharset(charset string) *encoding.Encoder {
    switch charset {
    case "ISO-8859-1":
        return charmap.ISO8859_1.NewEncoder()
    case "ISO-8859-15":
        return charmap.ISO8859_15.NewEncoder()
        // etc.
    }
    panic("Unknown charset \"" + charset + "\".")
}

See charset.Lookup(...), which returns a encoding.Encoding, from which you can call NewEncoder() and NewDecoder(), e.g.:

ss := []string{"ISO-8859-1", "ISO-8859-15", "bogus"}

for _, s := range ss {
    encoding, name := charset.Lookup(s)
    if encoding != nil {
        fmt.Printf("OK: encoding=%v, name=%q
", encoding, name)
        // encoder := encoding.NewEncoder()
        // decoder := encoding.NewDecoder()
    }
}
// OK: encoding=&{Windows 1252}, name="windows-1252"
// OK: encoding=&{ISO 8859-15}, name="iso-8859-15"