[Yaml-core] (backfill) YAML Meeting: Notes on RFC 822

[Clark C . E. <cc...@cl...>]

----- Forwarded message from "Clark C . Evans" <cc...@cl...> -----
Date: Thu, 17 May 2001 22:11:06 -0500
From: "Clark C . Evans" <cc...@cl...>
To: Brian Ingerson <briani@ActiveState.com>
Cc: Oren Ben-Kiki <or...@ri...>
Subject: Re: YAML & Pointers/References

(please correct if there are any mis-conceptions)

A few summary points about RFC822:

  - Every internet mail sent relies upon it. ;)
  - It is just a bunch of headers followed by
    a single blank line.  After the blank line
    the "message" is user defined.
  - In the headers, they use "folding" technique.
  - They also allow for "quoting" within the
    header.  Thus:
      Header: "Clark"
    and
      Header: Clark
    are identical.  The "" are used when spaces 
    are significant and special characters are
    needed.
  - The headers are a mapping
  - The headers are _not_ recursive
  - The header content can extend on as many
    lines as one desires, as long as it has
    a space character in column 1.
  - Headers beginning with an X- are open
    to use without an RFC.
  - For compliance, one must have three headers,
    "Date", "From", and "To"
  - There is a nasty comment mechanism using
    parenthesis which not many people use
  - Most of the headers are free form, 
    (especially the ones beginning with X-)
  - A few of the headers have very strict
    productions, including, as you can imagine
    Date.
  - The output of sendmail or any mail transfer
    agent is an RFC822 document.
  - RFC882 is the basis for MIME!!!  
 
Our impacts:

  - It looks alot like what we have except
    we are hierarchical, and we don't have
    as many nasty exceptions.
  - I think we will have an optional RFC822
    envelope (headers) seperated by a space 
    from the "real" data.  This allows us to 
    put in meta-data about our document, 
    including encoding information and processing
    instructions that arn't part of the data.
  - This will give us direct ability to
    have perl/python as the recipient of a 
    mail processing output (using |/my/program
    in /etc/aliases) and have the YAML library
    the *only* thing you need to process
    the mail.
  - We may want to have our syntax moderately
    similar so as to be an "extension of RFC822".
    This helps us with the super nerds since
    we arn't inventing our own thing, especially
    from the perspective of the XMLers.
  - I don't think we need to parse all of 
    the productions, but we should be able
    to minimally extract the content.
  - We can use MIME for "attachments"
  
I think we will have a simple rule.  If
the first set of "maps" contains "X-YAML-Version"
then we will assume it is an RFC 822 
envelope and treat it appropriately.

Thus, we don't have to cater to it too much,
but we should be as close as possible without
compromising our integrety.

Best,

Clark


  
 


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