Implement parsing of telephone numbers

[Simon-Laux]

maybe first only support +[country] [area] [number]?

[lk108]

That would be helpful for my use case.

[Simon-Laux]

android source code for this:

android/util/Patterns.java

    /**
     * This pattern is intended for searching for things that look like they
     * might be phone numbers in arbitrary text, not for validating whether
     * something is in fact a phone number.  It will miss many things that
     * are legitimate phone numbers.
     *
     * <p> The pattern matches the following:
     * <ul>
     * <li>Optionally, a + sign followed immediately by one or more digits. Spaces, dots, or dashes
     * may follow.
     * <li>Optionally, sets of digits in parentheses, separated by spaces, dots, or dashes.
     * <li>A string starting and ending with a digit, containing digits, spaces, dots, and/or dashes.
     * </ul>
     */
    public static final Pattern PHONE
        = Pattern.compile(                      // sdd = space, dot, or dash
                "(\\+[0-9]+[\\- \\.]*)?"        // +<digits><sdd>*
                + "(\\([0-9]+\\)[\\- \\.]*)?"   // (<digits>)<sdd>*
                + "([0-9][0-9\\- \\.]+[0-9])"); // <digit><digit|sdd>+<digit>

Looks there are also standards for it, like https://en.wikipedia.org/wiki/E.164

the German wikipedia page for telephone numbers also contains some example formats that are used in Germany, Switzerland and Austria: https://de.wikipedia.org/w/index.php?title=Rufnummer&oldid=236385081#Nationales