FWS handling in message ids

[galdor]

I am curious about the behaviour of the parser for message ids.

Mail.read_from_string("Message-ID: < foo\r\n @ example.com\r\n >\r\n").header.fields[0].element.message_ids[0]

Yields " foo @ example.com ". It means that the library will return different results for message ids which are semantically identical but syntactically different, for example:

• Message-ID: <foo@example.com>\r\n
• Message-ID: < foo@\t example.com> \r\n
• Message-ID: \r\n <\r\n\t foo \r\n @example.com>\r\n

Unless I am mistaken, all these representations are semantically identical (see RFC 5322 3.6.4., msg-id = [CFWS] "<" id-left "@" id-right ">" [CFWS])and I would expect message ids to be parsed as an object with two fields, left and right. In all these examples, left would be foo and right would be example.com.

Is there a reason behind the current behaviour?