The text/enriched MIME Content-type
RFC 1896

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Network Working Group                                         P. Resnick
Request for Comments: 1896                                      QUALCOMM
Obsoletes: 1523, 1563                                          A. Walker
Category: Informational                                         InterCon
                                                           February 1996

                  The text/enriched MIME Content-type

Status of this Memo

   This memo provides information for the Internet community.  This memo
   does not specify an Internet standard of any kind.  Distribution of
   this memo is unlimited.

Abstract

   MIME [RFC-1521] defines a format and general framework for the
   representation of a wide variety of data types in Internet mail. This
   document defines one particular type of MIME data, the text/enriched
   MIME type. The text/enriched MIME type is intended to facilitate the
   wider interoperation of simple enriched text across a wide variety of
   hardware and software platforms. This document is only a minor
   revision to the text/enriched MIME type that was first described in
   [RFC-1523] and [RFC-1563], and is only intended to be used in the
   short term until other MIME types for text formatting in Internet
   mail are developed and deployed.

The text/enriched MIME type

   In order to promote the wider interoperability of simple formatted
   text, this document defines an extremely simple subtype of the MIME
   content-type "text", the "text/enriched" subtype. The content-type
   line for this type may have one optional parameter, the "charset"
   parameter, with the same values permitted for the "text/plain" MIME
   content-type.

   The text/enriched subtype was designed to meet the following
   criteria:

   1. The syntax must be extremely simple to parse, so that even
      teletype-oriented mail systems can easily strip away the
      formatting information and leave only the readable text.

   2. The syntax must be extensible to allow for new formatting
      commands that are deemed essential for some application.

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   3. If the character set in use is ASCII or an 8-bit ASCII superset,
      then the raw form of the data must be readable enough to be
      largely unobjectionable in the event that it is displayed on the
      screen of the user of a non-MIME-conformant mail reader.

   4. The capabilities must be extremely limited, to ensure that it can
      represent no more than is likely to be representable by the
      user's primary word processor. While this limits what can be
      sent, it increases the likelihood that what is sent can be
      properly displayed.

   There are other text formatting standards which meet some of these
   criteria. In particular, HTML and SGML have come into widespread use
   on the Internet. However, there are two important reasons that this
   document further promotes the use of text/enriched in Internet mail
   over other such standards:

   1. Most MIME-aware Internet mail applications are already able to
      either properly format text/enriched mail or, at the very least,
      are able to strip out the formatting commands and display the
      readable text. The same is not true for HTML or SGML.

   2. The current RFC on HTML [RFC-1866] and Internet Drafts on SGML
      have many features which are not necessary for Internet mail, and
      are missing a few capabilities that text/enriched already has.

   For these reasons, this document is promoting the use of
   text/enriched until other Internet standards come into more
   widespread use. For those who will want to use HTML, Appendix B of
   this document contains a very simple C program that converts
   text/enriched to HTML 2.0 described in [RFC-1866].

Syntax

   The syntax of "text/enriched" is very simple. It represents text in a
   single character set--US-ASCII by default, although a different
   character set can be specified by the use of the "charset" parameter.
   (The semantics of text/enriched in non-ASCII character sets are
   discussed later in this document.) All characters represent
   themselves, with the exception of the "<" character (ASCII 60), which
   is used to mark the beginning of a formatting command. A literal
   less-than sign ("<") can be represented by a sequence of two such
   characters, "<<".

   Formatting instructions consist of formatting commands surrounded by
   angle brackets ("<>", ASCII 60 and 62). Each formatting command may
   be no more than 60 characters in length, all in US-ASCII, restricted
   to the alphanumeric and hyphen ("-") characters. Formatting commands

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   may be preceded by a solidus ("/", ASCII 47), making them negations,