Name

       lua-uri-urn-issn - ISSN URN support for Lua URI library

Description

       The class "uri.urn.issn" is used for URNs with the NID 'issn', that is, URIs which begin
       "urn:issn:".  It inherits from the uri.urn class.

       The URI is considered invalid if it doesn't have 8 digits, if there is anything extra in
       the NSS other than the digits and optional single hyphen, or if the checksum digit is
       wrong.

       As specified, the check digit is canonicalized to uppercase.  The canonical form has a
       single hyphen in the middle of the digits.

Methods

       All the methods defined in lua-uri(3) and lua-uri-urn(3) as supported, as well as the
       following:

       uri:issn_digits(...)
           Get or set the ISSN value as a string containing just the numbers.  There will be no
           hyphens in this value, and it should be exactly 8 characters long.

           If a new value is provided then it must not be nil, and will be validated in the
           normal way, causing an exception if it is invalid.

References

       This implements the 'issn' NID defined in "RFC 3044", and is consistent with the same NID
       suggested in "RFC 2288".