"""Parse U.S. phone numbers

This program is part of "Dive Into Python", a free Python book for
experienced programmers.  Visit http://diveintopython.org/ for the
latest version.
"""

__author__ = "Mark Pilgrim (mark@diveintopython.org)"
__version__ = "$Revision: 1.3 $"
__date__ = "$Date: 2004/05/05 21:57:19 $"
__copyright__ = "Copyright (c) 2002 Mark Pilgrim"
__license__ = "Python"

import re

class InvalidPhoneNumber(Exception): pass

phonePattern = re.compile(r"""
    ^            # match beginning of string
    \D*          # swallow anything that isn't numeric
    1?           # swallow leading 1, if present
    \D*          # swallow anything that isn't numeric
    (\d{3})      # capture 3-digit area code
    \D*          # swallow anything that isn't numeric
    (\d{3})      # capture 3-digit trunk
    \D*          # swallow anything that isn't numeric
    (\d{4})      # capture 4-digit number
    \D*          # swallow anything that isn't numeric
    (\d*)        # capture extension, if present
    """, re.VERBOSE)

def parsePhoneNumber(phoneNumber):
    match = phonePattern.search(phoneNumber)
    if match:
        return match.groups()
    else:
        raise InvalidPhoneNumber, phoneNumber