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FTSC                             FIDONET TECHNICAL STANDARDS COMMITTEE
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Publication:    FSP-1002
Revision:       2
Title:          Numeric reply indication in FTN subject lines
Author:         Odinn Sorensen, 2:236/77
Revision Date:  19 October 1997
Expiry Date:    11 October 1999
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Contents:
                1. Scope
                2. Format
                3. Reply procedure
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Status of this document
-----------------------

  This document is a Fidonet Standards Proposal (FSP).

  This document specifies an optional Fidonet standard protocol for
  the Fidonet community, and requests discussion and suggestions for
  improvements.

  This document is released to the public domain, and may be used,
  copied or modified for any purpose whatever.


Abstract
--------

  When making a reply to a message, there are currently three common
  ways to handle the subject line:

  1. Don't change it.
  2. Insert the string "Re: " in front of it.
  3. Insert the string "Re^n: " in front of it, where 'n' is increased
     by one if the original subject was already a reply.

  This document concerns itself with specifying the third variant.


1. Scope
--------

  This standard is specified for all FTN messages. Implementations
  will typically be message editors and other software that creates
  replies to messages.


2. Format
---------

  The format is "Re^n: ", where n is an unsigned integer number with
  one or more digits. The range of the number must be at least 0 to
  255. Negative numbers are not allowed. Note that there must be a
  space after the colon. The letters are not case sensitive, but
  uppercase 'R' and lowercase 'e' is recommended.


3. Reply procedure
------------------

  When making a reply that conforms to this specification, this
  procedure, or a functionally identical one, must be followed:

  1. If the original subject does not have a leading "Re: " or
     "Re^n: ", put the string "Re: " in front of it. Don't use a
     number here.

     Example:   "Hello world"  ->  "Re: Hello world"

  2. If the original subject has a leading "Re: ", put the string
     "Re^2: " in front of the subject.

     Example:   "Re: Hello world"  ->  "Re^2: Hello world"

  3. If the original subject has a leading "Re^n: ", increase the
     number 'n' by one and modify the subject accordingly.

     Example:   "Re^4: Hello world"  ->  "Re^5: Hello world"

  Notes:

  * The numbers 0 and 1 should not occur in the "Re^n: " string under
    normal circumstances, but a robust implementation should just
    increase the number in any case.

  * The number should not be increased beyond the range of the number
    type used in the implementation, or in other words, it should not
    roll around to zero. If it can't be increased, leave it alone.

  * When inserting the "Re: " or "Re^n: " string in front of the
    subject, information from the end might be lost, because the
    message storage or packet formats use fixed length subject fields.
    Intelligent subject-based reply linking software should be aware
    of this and try to link correctly anyway.


A. Author contact data
----------------------

  Odinn Sorensen
  Fidonet: 2:236/77
  E-mail:  odinn@goldware.dk
  WWW:     http://www.goldware.dk


B. History
----------

  Rev.1, 971011: First release.
  Rev.2, 971019: Added note that "Re" is not case sensitive.


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