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+Internet Engineering Task Force (IETF)                          N. Freed
+Request for Comments: 5784                                      S. Vedam
+Category: Standards Track                               Sun Microsystems
+ISSN: 2070-1721                                               March 2010
+
+
+      Sieve Email Filtering:  Sieves and Display Directives in XML
+
+Abstract
+
+   This document describes a way to represent Sieve email filtering
+   language scripts in XML.  Representing Sieves in XML is intended not
+   as an alternate storage format for Sieve but rather as a means to
+   facilitate manipulation of scripts using XML tools.
+
+   The XML representation also defines additional elements that have no
+   counterparts in the regular Sieve language.  These elements are
+   intended for use by graphical user interfaces and provide facilities
+   for labeling or grouping sections of a script so they can be
+   displayed more conveniently.  These elements are represented as
+   specially structured comments in regular Sieve format.
+
+Status of This Memo
+
+   This is an Internet Standards Track document.
+
+   This document is a product of the Internet Engineering Task Force
+   (IETF).  It represents the consensus of the IETF community.  It has
+   received public review and has been approved for publication by the
+   Internet Engineering Steering Group (IESG).  Further information on
+   Internet Standards is available in Section 2 of RFC 5741.
+
+   Information about the current status of this document, any errata,
+   and how to provide feedback on it may be obtained at
+   http://www.rfc-editor.org/info/rfc5784.
+
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+Freed & Vedam                Standards Track                    [Page 1]
+
+RFC 5784             An XML Representation for Sieve          March 2010
+
+
+Copyright Notice
+
+   Copyright (c) 2010 IETF Trust and the persons identified as the
+   document authors.  All rights reserved.
+
+   This document is subject to BCP 78 and the IETF Trust's Legal
+   Provisions Relating to IETF Documents
+   (http://trustee.ietf.org/license-info) in effect on the date of
+   publication of this document.  Please review these documents
+   carefully, as they describe your rights and restrictions with respect
+   to this document.  Code Components extracted from this document must
+   include Simplified BSD License text as described in Section 4.e of
+   the Trust Legal Provisions and are provided without warranty as
+   described in the Simplified BSD License.
+
+Table of Contents
+
+   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
+   2.  Conventions Used in This Document  . . . . . . . . . . . . . .  4
+   3.  Grammatical Structure of Sieve . . . . . . . . . . . . . . . .  4
+   4.  XML Representation of Sieve  . . . . . . . . . . . . . . . . .  6
+     4.1.  XML Display Directives . . . . . . . . . . . . . . . . . .  9
+     4.2.  Structured Comments  . . . . . . . . . . . . . . . . . . . 10
+     4.3.  Validation . . . . . . . . . . . . . . . . . . . . . . . . 11
+   5.  Security Considerations  . . . . . . . . . . . . . . . . . . . 11
+   6.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 11
+   7.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 12
+     7.1.  Normative References . . . . . . . . . . . . . . . . . . . 12
+     7.2.  Informative References . . . . . . . . . . . . . . . . . . 13
+   Appendix A.  Extended Example  . . . . . . . . . . . . . . . . . . 14
+   Appendix B.  XML Schema for Sieves in XML  . . . . . . . . . . . . 21
+   Appendix C.  Relax NG Schema for Sieves in XML . . . . . . . . . . 24
+   Appendix D.  Stylesheet for Conversion from XML  . . . . . . . . . 26
+   Appendix E.  Acknowledgements  . . . . . . . . . . . . . . . . . . 32
+
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+Freed & Vedam                Standards Track                    [Page 2]
+
+RFC 5784             An XML Representation for Sieve          March 2010
+
+
+1.  Introduction
+
+   Sieve [RFC5228] is a language for filtering email messages at or
+   around the time of final delivery.  It is designed to be
+   implementable on either a mail client or mail server.  It is meant to
+   be extensible, simple, and independent of access protocol, mail
+   architecture, and operating system, and it is intended to be
+   manipulated by a variety of different user interfaces.
+
+   Some user interface environments have extensive existing facilities
+   for manipulating material represented in XML [XML].  While adding
+   support for alternate data syntaxes may be possible in most if not
+   all of these environments, it may not be particularly convenient to
+   do so.  The obvious way to deal with this issue is to map Sieves into
+   XML, possibly on a separate back-end system, manipulate the XML, and
+   convert it back to normal Sieve format.
+
+   The fact that conversion into and out of XML may be done as a
+   separate operation on a different system argues strongly for defining
+   a common XML representation for Sieve.  This way, different front-end
+   user interfaces can be used with different back-end mapping and
+   storage facilities.
+
+   Another issue with the creation and manipulation of Sieve scripts by
+   user interfaces is that the language is strictly focused on
+   describing email filtering operations.  The language contains no
+   mechanisms for indicating how a given script should be presented in a
+   user interface.  Such information can be represented in XML very
+   easily, so it makes sense to define a framework to do this as part of
+   the XML format.  A structured comment convention is then used to
+   retain this information when the script is converted to normal Sieve
+   format.
+
+   It should be noted, however, that the ability for different front
+   ends to use the same mapping and storage facilities does not mean
+   that the additional XML information produced by different front ends
+   will interoperate.
+
+   Various Sieve extensions have already been defined, e.g., [RFC5183],
+   [RFC5229], [RFC5230], [RFC5231], [RFC5232], [RFC5233], [RFC5235],
+   [RFC5293], and more are planned.  The set of extensions available
+   varies from one implementation to the next and may even change as a
+   result of configuration choices.  It is therefore essential that the
+   XML representation of Sieve be able to accommodate Sieve extensions
+   without requiring schema changes.  It is also desirable that Sieve
+   extensions not require changes to the code that converts to and from
+   the XML representation.
+
+
+
+
+Freed & Vedam                Standards Track                    [Page 3]
+
+RFC 5784             An XML Representation for Sieve          March 2010
+
+
+   This specification defines an XML representation for Sieve scripts
+   and explains how the conversion process to and from XML works.  The
+   XML representation is capable of accommodating any future Sieve
+   extension as long as the underlying Sieve grammar remains unchanged.
+   Furthermore, code that converts from XML to the normal Sieve format
+   requires no changes to accommodate extensions, while code used to
+   convert from normal Sieve format to XML only requires changes when
+   new control commands are added -- a rare event.  An XML Schema, Relax
+   NG Schema, and a sample stylesheet to convert from XML format are
+   also provided in the appendices.
+
+2.  Conventions Used in This Document
+
+   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
+   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
+   document are to be interpreted as described in RFC 2119 [RFC2119].
+
+   The term "processor" is used throughout this document to refer to
+   agents that convert Sieve to and from the XML representation.  The
+   term "editor" refers to agents that operate on, possibly creating or
+   modifying, Sieves in XML format.
+
+3.  Grammatical Structure of Sieve
+
+   The Sieve language is designed to be highly extensible without making
+   any changes to the basic language syntax.  Accordingly, the syntax of
+   Sieve, defined in Section 8 of [RFC5228], is entirely structural in
+   nature and employs no reserved words of any sort.
+
+   Structurally, a Sieve script consists of a series of commands.  Each
+   command, in turn, consists of an identifier, zero or more arguments,
+   an optional test or test-list, and finally an optional block
+   containing another series of commands.  Commands are further broken
+   down into controls and actions, although this distinction cannot be
+   determined from the grammar.
+
+   Some example Sieve controls are:
+
+   stop;               <-- No arguments, test, or command block
+   require "fileinto"; <-- Control with a single argument
+   if true {stop;}     <-- Control with test and command block
+
+   Some examples of Sieve actions are:
+
+discard;            <-- Action with no arguments, test, or command block
+fileinto "folder";  <-- Action with an argument
+
+
+
+
+
+Freed & Vedam                Standards Track                    [Page 4]
+
+RFC 5784             An XML Representation for Sieve          March 2010
+
+
+   At the time of this writing, there are no controls defined that
+   accept both arguments and a test.  Similarly, there are currently no
+   defined actions that allow either a test or a command block.
+   Nevertheless, the Sieve grammar allows such constructs to be defined
+   by some future extension.
+
+   A test consists of an identifier followed by zero or more arguments,
+   then another test or test-list.  Unlike commands, tests cannot be
+   followed by a command block.
+
+   Here are some examples of Sieve tests.  Note that such tests have to
+   appear as part of a command in order to be syntactically valid:
+
+   true                <-- Test with no argument or subordinate test
+   envelope "to" "me@example.com" <-- Test with several arguments
+   header :is "from" "you@example.com" <-- Test with tagged argument
+
+   Command or test arguments can be either string lists, whole numbers,
+   or tags.  (Tags are simply identifiers preceded by a colon.)  Note
+   that although the Sieve grammar treats single strings as a degenerate
+   case of a string list, some tests or actions have arguments that can
+   only be individual strings, not lists.
+
+   Here is an example showing the use of both a test-list and a string
+   list:
+
+   if anyof (not exists ["From", "Date"],
+             header :contains "from" "fool@example.edu") {
+     discard;
+   }
+
+   Extensions can add new controls, actions, tests, or arguments to
+   existing controls or actions.  Extensions have also changed how
+   string content is interpreted, although this is not relevant to this
+   specification.  However, it is especially important to note that so
+   far, only one of the many defined Sieve extensions -- the
+   foreverypart extension [RFC5703] -- has added new controls to the
+   language.  It seems safe to assume that, due to their nature, future
+   addition of controls will be relatively rare.
+
+   Finally, comments are allowed between lexical elements in a Sieve
+   script.  One important use case for comments is encoding meta-data
+   about the script, a facility that is lacking in the Sieve language.
+   Therefore, comments need to be preserved in the XML representation.
+
+
+
+
+
+
+
+Freed & Vedam                Standards Track                    [Page 5]
+
+RFC 5784             An XML Representation for Sieve          March 2010
+
+
+4.  XML Representation of Sieve
+
+   Sieve controls and actions are represented in XML as "control" or
+   "action" elements, respectively.  The command's identifier appears as
+   a name attribute on the element itself.  This is the only attribute
+   allowed on controls and actions -- arguments, tests, test-lists, and
+   nested command blocks are all represented as nested elements.  While
+   naming the element after the control or action itself may seem like a
+   better choice, doing so would result in extensions requiring frequent
+   corresponding schema changes.
+
+   The example Sieve controls shown in the previous section would be
+   represented as these XML fragments:
+
+    <control name="stop"/>
+
+    <control name="require"><str>fileinto</str></control>
+
+    <control name="if">
+     <test name="true"/><control name="stop"/>
+    </control>
+
+   The example Sieve actions shown above would appear in XML as:
+
+   <action name="discard"/>
+   <action name="fileinto"><str>folder</str></action>
+
+   The separation of controls from actions in the XML representation
+   means that conversion from normal Sieve format to XML has to be able
+   to distinguish between controls and actions.  This is easily done by
+   maintaining a list of all known controls since experience indicates
+   new controls are rarely added.  At the time of this writing, the list
+   of defined controls consists of:
+
+   1.  if [RFC5228],
+
+   2.  stop [RFC5228],
+
+   3.  require [RFC5228],
+
+   4.  foreverypart [RFC5703], and
+
+   5.  break [RFC5703].
+
+   It should be noted that with this approach unknown controls will
+   simply be treated as actions and can be passed back and forth between
+   the two representations.  The treatment of a control as an action is
+
+
+
+
+Freed & Vedam                Standards Track                    [Page 6]
+
+RFC 5784             An XML Representation for Sieve          March 2010
+
+
+   unlikely to cause other issues since knowledge of a control's
+   language semantics is almost always required to take advantage of it.
+
+   Tests are represented in the same basic way as controls and actions,
+   that is, as a "test" element with a name attribute giving the test
+   identifier.  For example, the following XML fragments show various
+   types of tests:
+
+   <test name="true"/>
+
+   <test name="envelope"/>
+     <str>to</str><str>me@example.com</str>
+   </test>
+
+   <test name="header"/>
+     <tag>is</tag><str>from</str><str>you@example.com</str>
+   </test>
+
+   String, number, and tag arguments are represented as "str", "num",
+   and "tag" elements, respectively.  The actual string, number, or tag
+   identifier appears as text inside the element.  None of these
+   elements have any defined attributes.  Several examples of arguments
+   have already appeared in the preceding control, action, and test
+   examples.  Any whitespace in the str body content MUST be preserved
+   by the processor.  Also, note that since strings and tags are
+   represented as element text, any quotes or other syntactic elements
+   required in the regular Sieve representation are dropped rather than
+   being carried over into the XML.
+
+   String list arguments are represented as a "list" element, which in
+   turn contains one or more str elements.  Note that this allows the
+   distinction between a single string and a string list containing a
+   single string to be preserved.  This is not essential since a list
+   containing a single string could simply be mapped to a string, but it
+   seems prudent to maintain the distinction when mapping to and from
+   XML.
+
+   Nested command blocks appear as a series of control or action
+   elements inside of an outer control or action element.  No block
+   element is needed since an inner command block can only appear once
+   and only after any arguments, tests, or test-lists.  For example:
+
+
+
+
+
+
+
+
+
+
+Freed & Vedam                Standards Track                    [Page 7]
+
+RFC 5784             An XML Representation for Sieve          March 2010
+
+
+   <control name="if">
+     <test name="anyof">
+       <test name="not">
+         <test name="exists">
+           <list><str>From</str><str>Date</str></list>
+         </test>
+       </test>
+       <test name="header">
+         <tag>contains</tag>
+         <str>from</str>
+         <str>fool@example.edu</str>
+       </test>
+     </test>
+     <action name="discard"/>
+   </control>
+
+   Sieve comments are mapped to a special "comment" element in XML.
+   Both hash and bracketed comments are mapped to the same construct so
+   the distinction between the two is lost in XML.  XML comments are not
+   used because some XML tools do not make it convenient to access
+   comment nodes.
+
+   Comments are allowed between commands and inside "test" elements.
+   But comments aren't allowed directly inside commands -- due to
+   limitations of XML Schema, special enclosing "preamble" and
+   "postamble" elements are needed:
+
+   <control name="if">
+     <preamble>
+       <comment>Check to see if message should be discarded</comment>
+     </preamble>
+     <test name="anyof">
+       <test name="not">
+         <test name="exists">
+           <list><str>From</str><str>Date</str></list>
+         </test>
+       </test>
+       <test name="header">
+         <tag>contains</tag>
+         <str>from</str>
+         <str>fool@example.edu</str>
+       </test>
+     </test>
+     <action name="discard"/>
+     <postamble>
+       <comment>End of discard check</comment>
+     </postamble>
+   </control>
+
+
+
+Freed & Vedam                Standards Track                    [Page 8]
+
+RFC 5784             An XML Representation for Sieve          March 2010
+
+
+4.1.  XML Display Directives
+
+   Sometimes graphical user interfaces are a convenient way to provide
+   Sieve management functions to users.  These interfaces typically
+   summarize/annotate/group/display Sieve script(s) in an intuitive way
+   for end users.
+
+   To do this effectively, the graphical user interface may require
+   additional information about the Sieve script itself.  That
+   information or "meta-data" might include, but is not limited to, a
+   Sieve name (identifying the current Sieve), whether the Sieve is
+   enabled or disabled, and the order in which the parts of the Sieve
+   are presented to the user.  The graphical user interface may also
+   choose to provide mechanisms to allow the user to modify the script.
+
+   It is often useful for a graphical user interface to group related
+   Sieve script elements and provide an interface that displays these
+   groups separately so they can be managed as a single object.  Some
+   examples include Sieve statements that together provide vacation
+   responders, blacklists/whitelists, and other types of filtering
+   controls.
+
+   Some advanced graphical user interfaces may even provide a natural
+   language representation of a Sieve script and/or an advanced
+   interface to present Sieve statements directly to the user.
+
+   A graphical user interface may also choose to support only a subset
+   of action commands in the Sieve language (and its extensions), and so
+   a mechanism to indicate the extent of support and characterize the
+   relationships between those supported action commands and the test
+   (with its arguments) is immensely useful and probably required for
+   clients that may not have complete knowledge of Sieve grammar and
+   semantics.
+
+   The Sieve language contains no mechanisms for indicating how a given
+   script should be presented in a user interface.  The language also
+   does not contain any specific mechanisms to represent other sorts of
+   meta-data about the script.  Providing support for such meta-data as
+   part of a Sieve script is currently totally implementation specific
+   and is usually done by imposing some type of structure on comments.
+
+   However, such information can be represented in XML very easily, so
+   it makes sense to define a framework to do this as part of the XML
+   format.  Implementations MAY choose to use structured comments to
+   retain this information when the script is converted to normal Sieve
+   format.
+
+
+
+
+
+Freed & Vedam                Standards Track                    [Page 9]
+
+RFC 5784             An XML Representation for Sieve          March 2010
+
+
+   The sample schemata for the XML representation of Sieve allows XML in
+   foreign namespaces to be inserted in the same places "comment"
+   elements can appear in Sieve scripts.  This is the preferred means of
+   including additional information.  Alternately, the schema defines
+   two display directives -- displayblock and displaydata -- as
+   containers for meta-data needed by graphical user interfaces.
+
+   Editors MAY use displayblock, displaydata, and foreign namespaces to
+   associate meta-data.  Some editors find it inconvenient to preserve
+   this additional data during an editing session.  Editors MAY preserve
+   this data during an editing session for compatibility with other
+   editors.
+
+   The displayblock element can be used to enclose any number of Sieve
+   statements at any level.  It is semantically meaningless to the Sieve
+   script itself.  It allows an arbitrary set of attributes.
+   Implementations MAY use this to provide many simple, display-related
+   meta-data for the Sieve such as Sieve identifier, group identifier,
+   order of processing, etc.
+
+   The displaydata element supports any number of arbitrary child
+   elements.  Implementations MAY use this to represent complex data
+   about that Sieve such as a natural language representation of Sieve
+   or a way to provide the Sieve script directly.
+
+4.2.  Structured Comments
+
+   Since the XML representation is not intended as a storage format,
+   there needs to be a way to preserve the additional information that
+   can be included in the XML representation in the normal Sieve syntax.
+   This is done through the use of three structured comment conventions:
+
+   1.  XML content in other namespaces is placed in Sieve bracketed
+       comments beginning with the string "/* [/" and ending with the
+       string "/] */".
+
+   2.  The content of displaydata elements is placed in Sieve bracketed
+       comments beginning with the string "/* [|" and ending with the
+       string "|] */".
+
+   3.  The beginning of a displayblock element is mapped to a bracketed
+       Sieve comment beginning with the string "/* [*", which then lists
+       any displayblock attribute names and values in XML format.  The
+       end of a displayblock element is mapped to a comment of the form
+       "*] */".
+
+   Processors MUST preserve the additional information allowed in the
+   XML format and SHOULD use the structured comment format shown above.
+
+
+
+Freed & Vedam                Standards Track                   [Page 10]
+
+RFC 5784             An XML Representation for Sieve          March 2010
+
+
+   Note: If "*/" is found in the XML content, when mapped into a
+   comment, it would prematurely terminate that comment.  Escaping this
+   sequence would often be inconvenient for processors.  Editors SHALL
+   NOT include "*/" within displayblock, displaydata, or foreign markup.
+   Processors MAY regard documents containing "*/" in foreign markup,
+   displayblock, or displaydata as invalid.
+
+4.3.  Validation
+
+   A processor MAY validate documents against a schema, and it MAY
+   reject any that do not conform.  For any document that a processor
+   does not reject as invalid, any markup that the processor cannot
+   understand by reference to this specification MAY be discarded.
+
+   Note that example Relax NG and XML Schema are given in the appendices
+   below.
+
+5.  Security Considerations
+
+   Any syntactically valid Sieve script can be represented in XML.
+   Accordingly, all security considerations applicable to Sieve and any
+   extensions used also apply to the XML representation.
+
+   The use of XML carries its own security risks.  Section 7 of RFC 3470
+   [RFC3470] discusses these risks.
+
+   It is axiomatic that a Sieve editor must be trusted to do what the
+   user specifies.  If XML formats are used, this trust necessarily must
+   extend to the components involved in converting to and from XML
+   format.
+
+   Arbitrary data can be included using other namespaces or placed in
+   the extensible displayblock and displaydata constructs defined in
+   this specification, possibly including entire scripts and other
+   executable content in languages other than Sieve.  Such material will
+   necessarily have its own security considerations, which are beyond
+   the scope of this document.
+
+6.  IANA Considerations
+
+   This section registers a new XML namespace per the procedures in RFC
+   3688 [RFC3688].
+
+
+
+
+
+
+
+
+
+Freed & Vedam                Standards Track                   [Page 11]
+
+RFC 5784             An XML Representation for Sieve          March 2010
+
+
+   URI:  urn:ietf:params:xml:ns:sieve
+
+   Registrant Contact:  IETF Sieve working group
+                        <ietf-mta-filters@imc.org>
+
+   XML:
+
+     BEGIN
+     <?xml version="1.0"?>
+     <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML Basic 1.0//EN"
+       "http://www.w3.org/TR/xhtml-basic/xhtml-basic10.dtd">
+     <html xmlns="http://www.w3.org/1999/xhtml">
+     <head>
+       <meta http-equiv="content-type"
+             content="text/html;charset=iso-8859-1"/>
+       <title>Sieve Namespace</title>
+     </head>
+     <body>
+       <h1>Namespace for Sieve Language objects expressed in XML</h1>
+       <h2>urn:ietf:params:xml:ns:sieve</h2>
+       <p>See <a href="http://www.rfc-editor.org/rfc/rfc5784.txt">
+        RFC 5784</a>.
+       </p>
+     </body>
+     </html>
+     END
+
+7.  References
+
+7.1.  Normative References
+
+   [OASISRNC]  Clark, J., "RELAX NG Compact Syntax", OASIS Committee
+               Specification rnc, November 2002.
+
+   [RFC2119]   Bradner, S., "Key words for use in RFCs to Indicate
+               Requirement Levels", BCP 14, RFC 2119, March 1997.
+
+   [RFC3470]   Hollenbeck, S., Rose, M., and L. Masinter, "Guidelines
+               for the Use of Extensible Markup Language (XML)
+               within IETF Protocols", BCP 70, RFC 3470, January 2003.
+
+   [RFC3688]   Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
+               January 2004.
+
+   [RFC5228]   Guenther, P. and T. Showalter, "Sieve: An Email Filtering
+               Language", RFC 5228, January 2008.
+
+
+
+
+
+Freed & Vedam                Standards Track                   [Page 12]
+
+RFC 5784             An XML Representation for Sieve          March 2010
+
+
+   [XML]       Bray, T., Paoli, J., Sperberg-McQueen, C., Maler, E., and
+               F. Yergeau, "Extensible Markup Language (XML) 1.0 (Fifth
+               Edition)", W3C REC-xml-20081126, November 2008,
+               <http://www.w3.org/TR/2008/REC-xml-20081126/>.
+
+7.2.  Informative References
+
+   [RFC5183]   Freed, N., "Sieve Email Filtering: Environment
+               Extension", RFC 5183, May 2008.
+
+   [RFC5229]   Homme, K., "Sieve Email Filtering: Variables Extension",
+               RFC 5229, January 2008.
+
+   [RFC5230]   Showalter, T. and N. Freed, "Sieve Email Filtering:
+               Vacation Extension", RFC 5230, January 2008.
+
+   [RFC5231]   Segmuller, W. and B. Leiba, "Sieve Email Filtering:
+               Relational Extension", RFC 5231, January 2008.
+
+   [RFC5232]   Melnikov, A., "Sieve Email Filtering: Imap4flags
+               Extension", RFC 5232, January 2008.
+
+   [RFC5233]   Murchison, K., "Sieve Email Filtering: Subaddress
+               Extension", RFC 5233, January 2008.
+
+   [RFC5235]   Daboo, C., "Sieve Email Filtering: Spamtest and Virustest
+               Extensions", RFC 5235, January 2008.
+
+   [RFC5293]   Degener, J. and P. Guenther, "Sieve Email Filtering:
+               Editheader Extension", RFC 5293, August 2008.
+
+   [RFC5703]   Hansen, T. and C. Daboo, "Sieve Email Filtering: MIME
+               Part Tests, Iteration, Extraction, Replacement, and
+               Enclosure", RFC 5703, October 2009.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Freed & Vedam                Standards Track                   [Page 13]
+
+RFC 5784             An XML Representation for Sieve          March 2010
+
+
+Appendix A.  Extended Example
+
+   The example Sieve script given in Section 9 of [RFC5228] would be
+   represented in XML as the following code component:
+
+   <sieve xmlns="urn:ietf:params:xml:ns:sieve">
+     <comment>
+       Example Sieve Filter
+       Declare any optional features or extensions used by the script
+     </comment>
+
+     <control name="require">
+       <str>fileinto</str>
+     </control>
+     <comment>
+       Handle messages from known mailing lists.
+       Move messages from IETF filter discussion list to filter mailbox.
+     </comment>
+     <control name="if">
+       <test name="header">
+         <tag>is</tag>
+         <str>Sender</str>
+         <str>owner-ietf-mta-filters@imc.org</str>
+       </test>
+       <action name="fileinto">
+         <str>filter</str>
+       </action>
+       <postamble>
+         <comment>move to "filter" mailbox</comment>
+       </postamble>
+     </control>
+
+     <comment>
+       Keep all messages to or from people in my company.
+     </comment>
+     <control name="elsif">
+       <test name="address">
+         <tag>domain</tag>
+         <tag>is</tag>
+         <list>
+           <str>From</str>
+           <str>To</str>
+         </list>
+         <str>example.com</str>
+       </test>
+       <action name="keep"/>
+     </control>
+
+
+
+
+Freed & Vedam                Standards Track                   [Page 14]
+
+RFC 5784             An XML Representation for Sieve          March 2010
+
+
+     <comment>
+       Try and catch unsolicited email.  If a message is not to me,
+       or it contains a subject known to be spam, file it away.
+     </comment>
+     <control name="elsif">
+       <test name="anyof">
+         <test name="not">
+           <test name="address">
+             <tag>all</tag>
+             <tag>contains</tag>
+             <list>
+               <str>To</str>
+               <str>Cc</str>
+               <str>Bcc</str>
+             </list>
+             <str>me@example.com</str>
+           </test>
+         </test>
+         <test name="header">
+           <tag>matches</tag>
+           <str>subject</str>
+           <list>
+             <str>*make*money*fast*</str>
+             <str>*university*dipl*mas*</str>
+           </list>
+         </test>
+       </test>
+       <action name="fileinto">
+         <str>spam</str>
+       </action>
+     </control>
+     <control name="else">
+       <preamble>
+         <comment>
+           Move all other (non-company) mail to "personal"
+           mailbox.
+         </comment>
+       </preamble>
+       <action name="fileinto">
+         <str>personal</str>
+       </action>
+     </control>
+
+   </sieve>
+
+
+
+
+
+
+
+Freed & Vedam                Standards Track                   [Page 15]
+
+RFC 5784             An XML Representation for Sieve          March 2010
+
+
+   The same script could be annotated with graphical display hints in a
+   variety of ways.  Three possible code components that do this are:
+
+   <sieve xmlns="urn:ietf:params:xml:ns:sieve">
+
+     <control name="require">
+       <str>fileinto</str>
+     </control>
+
+     <displayblock name="File filter list mail" order="1"
+                   group="FILE_TO_FOLDER" enable="true">
+       <control name="if">
+         <test name="header">
+           <tag>is</tag>
+           <str>Sender</str>
+           <str>owner-ietf-mta-filters@imc.org</str>
+         </test>
+         <action name="fileinto">
+           <str>filter</str>
+         </action>
+       </control>
+     </displayblock>
+
+     <displayblock name="Keep all company mail" order="2"
+                   group="KEEP_MESSAGE" enable="true">
+       <control name="elsif">
+         <test name="address">
+           <tag>domain</tag>
+           <tag>is</tag>
+           <list>
+             <str>From</str>
+             <str>To</str>
+           </list>
+           <str>example.com</str>
+         </test>
+         <action name="keep"/>
+      </control>
+     </displayblock>
+
+     <displayblock name="File suspected spam" order="3"
+                   group="FILE_TO_FOLDER" enable="true">
+        <control name="elsif">
+          <test name="anyof">
+            <test name="not">
+              <test name="address">
+                <tag>all</tag>
+                <tag>contains</tag>
+                <list>
+
+
+
+Freed & Vedam                Standards Track                   [Page 16]
+
+RFC 5784             An XML Representation for Sieve          March 2010
+
+
+                  <str>To</str>
+                  <str>Cc</str>
+                  <str>Bcc</str>
+                </list>
+                <str>me@example.com</str>
+              </test>
+            </test>
+            <test name="header">
+              <tag>matches</tag>
+              <str>subject</str>
+              <list>
+                <str>*make*money*fast*</str>
+                <str>*university*dipl*mas*</str>
+              </list>
+            </test>
+          </test>
+          <action name="fileinto">
+            <str>spam</str>
+          </action>
+        </control>
+      </displayblock>
+
+     <displayblock name="File noncompany mail as personal" order="4"
+                   group="FILE_TO_FOLDER" enable="true">
+       <control name="else">
+         <action name="fileinto">
+           <str>personal</str>
+         </action>
+       </control>
+     </displayblock>
+
+   </sieve>
+
+   Note that since displayblock elements are semantically null as far as
+   the script itself is concerned, they can be used to group structures
+   like elsif and else that are tied to statements in other groups.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Freed & Vedam                Standards Track                   [Page 17]
+
+RFC 5784             An XML Representation for Sieve          March 2010
+
+
+   The representation of this script in regular Sieve syntax uses
+   structured comments:
+
+   require "fileinto";
+   /* [* name="File filter list mail" order="1"
+         group="FILE_TO_FOLDER" enable="true" */
+   if header :is "Sender" "owner-ietf-mta-filters@imc.org"
+   {
+     fileinto "filter";
+   }
+   /* *] */
+   /* [* name="Keep all company mail" order="2"
+         group="KEEP_MESSAGE" enable="true" */
+   elsif address :domain :is [ "From", "To" ] "example.com"
+   {
+     keep;
+   }
+   /* *] */
+   /* [* name="File suspected spam" order="3"
+         group="FILE_TO_FOLDER" enable="true" */
+   elsif anyof ( not ( address :all :contains [ "To", "Cc", "Bcc" ]
+                       "me@example.com" ),
+                 header :matches "subject" [ "*make*money*fast*",
+                                             "*university*dipl*mas*" ] )
+   {
+     fileinto "spam";
+   }
+   /* *] */
+   /* [* name="File noncompany mail as personal" order="4"
+         group="FILE_TO_FOLDER" enable="true" */
+   else
+   {
+     fileinto "personal";
+   }
+   /* *] */
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Freed & Vedam                Standards Track                   [Page 18]
+
+RFC 5784             An XML Representation for Sieve          March 2010
+
+
+   A separate namespace can be used to embed text or structured
+   information:
+
+   <sieve xmlns="urn:ietf:params:xml:ns:sieve"
+          xmlns:nls="http://example.com/nls">
+
+     <nls:interpretation>
+       If the email header "Sender" is owner-ietf-mta-filters@imc.org,
+       then file it into the "filter" folder.
+
+       Otherwise, if the address in the "From" or "To" has a domain
+       that is "example.com", then keep it.
+
+       Otherwise, messages meeting with any of these conditions:
+
+       (1) None of the addresses in "To", "Cc", or "Bcc" contain
+           the domain "example.com".
+
+       (2) The "Subject" field matches the pattern *make*money*fast*
+           or *university*dipl*mas*, then file it into the "spam"
+           folder.
+
+       If all else fails, then file the message in the "personal"
+       folder.
+     </nls:interpretation>
+
+     ... the actual Sieve script ...
+
+   </sieve>
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Freed & Vedam                Standards Track                   [Page 19]
+
+RFC 5784             An XML Representation for Sieve          March 2010
+
+
+   Alternately, displaydata elements can be used to accomplish the same
+   thing:
+
+   <sieve xmlns="urn:ietf:params:xml:ns:sieve">
+
+     <displaydata>
+       <nls-interpretation>
+         If the email header "Sender" is owner-ietf-mta-filters@imc.org,
+         then file it into the "filter" folder.
+
+         Otherwise, if the address in the "From" or "To" has a domain
+         that is "example.com", then keep it.
+
+         Otherwise, messages meeting with any of these conditions:
+
+         (1) None of the addresses in "To","Cc", or "Bcc" contain
+             the domain "example.com".
+
+         (2) The "Subject" field matches the pattern *make*money*fast*
+             or *university*dipl*mas*, then file it into the "spam"
+             folder.
+
+         If all else fails, then file the message in the "personal"
+         folder.
+       </nls-interpretation>
+     </displaydata>
+
+     ... the actual Sieve script ...
+
+   </sieve>
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Freed & Vedam                Standards Track                   [Page 20]
+
+RFC 5784             An XML Representation for Sieve          March 2010
+
+
+   Again, structured comments are used to represent this in regular
+   Sieve syntax:
+
+     /* [|
+       <nls-interpretation>
+         If the email header "Sender" is owner-ietf-mta-filters@imc.org,
+         then file it into the "filter" folder.
+
+         Otherwise, if the address in the "From" or "To" has a domain
+         that is "example.com", then keep it.
+
+         Otherwise, messages meeting with any of these conditions:
+
+         (1) None of the addresses in "To","Cc", or "Bcc" contain
+             the domain "example.com".
+
+         (2) The "Subject" field matches the pattern *make*money*fast*
+             or *university*dipl*mas*, then file it into the "spam"
+             folder.
+
+         If all else fails, then file the message in the "personal"
+         folder.
+       </nls-interpretation>
+     |] */
+
+     ... the actual Sieve script ...
+
+Appendix B.  XML Schema for Sieves in XML
+
+   This appendix is informative.  The following code component is an XML
+   Schema for the XML representation of Sieve scripts.  Most of the
+   elements employing a complex content model allow use of elements in
+   other namespaces, subject to lax XML Schema validation rules.
+   Additionally, displaydata elements can be used to encapsulate
+   arbitrary XML content.  Finally, displayblock elements can be used as
+   a general-purpose grouping mechanism -- arbitrary attributes are
+   allowed on displayblock elements.
+
+   <?xml version="1.0" encoding="UTF-8"?>
+
+   <xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"
+               xmlns="urn:ietf:params:xml:ns:sieve"
+               targetNamespace="urn:ietf:params:xml:ns:sieve">
+
+     <xsd:element name="sieve">
+       <xsd:complexType>
+         <xsd:sequence>
+           <xsd:choice maxOccurs="unbounded" minOccurs="0">
+
+
+
+Freed & Vedam                Standards Track                   [Page 21]
+
+RFC 5784             An XML Representation for Sieve          March 2010
+
+
+             <xsd:element ref="control"/>
+             <xsd:element ref="action"/>
+             <xsd:element ref="displayblock"/>
+             <xsd:element ref="displaydata"/>
+             <xsd:element ref="comment"/>
+             <xsd:any namespace="##other" processContents="lax"/>
+           </xsd:choice>
+         </xsd:sequence>
+       </xsd:complexType>
+     </xsd:element>
+
+     <xsd:element name="comment" type="xsd:string"/>
+
+     <xsd:complexType name="ambles">
+       <xsd:choice minOccurs="0" maxOccurs="unbounded">
+         <xsd:element ref="displaydata"/>
+         <xsd:element ref="comment"/>
+         <xsd:any namespace="##other" processContents="lax"/>
+      </xsd:choice>
+     </xsd:complexType>
+
+     <xsd:element name="preamble" type="ambles"/>
+     <xsd:element name="postamble" type="ambles"/>
+
+     <xsd:complexType name="command">
+       <xsd:sequence>
+         <xsd:element ref="preamble" minOccurs="0" maxOccurs="1"/>
+         <xsd:choice minOccurs="0" maxOccurs="unbounded">
+           <xsd:element ref="str"/>
+           <xsd:element ref="num"/>
+           <xsd:element ref="list"/>
+           <xsd:element ref="tag"/>
+         </xsd:choice>
+         <xsd:element ref="test" minOccurs="0" maxOccurs="1"/>
+         <xsd:choice minOccurs="0" maxOccurs="unbounded">
+           <xsd:element ref="control"/>
+           <xsd:element ref="action"/>
+           <xsd:element ref="displayblock"/>
+         </xsd:choice>
+         <xsd:element ref="postamble" minOccurs="0" maxOccurs="1"/>
+       </xsd:sequence>
+       <xsd:attribute use="required" name="name" type="identifier"/>
+     </xsd:complexType>
+
+     <xsd:element name="control" type="command"/>
+     <xsd:element name="action" type="command"/>
+
+     <xsd:element name="test">
+
+
+
+Freed & Vedam                Standards Track                   [Page 22]
+
+RFC 5784             An XML Representation for Sieve          March 2010
+
+
+       <xsd:complexType>
+         <xsd:sequence>
+           <xsd:choice minOccurs="0" maxOccurs="unbounded">
+             <xsd:element ref="str"/>
+             <xsd:element ref="num"/>
+             <xsd:element ref="list"/>
+             <xsd:element ref="tag"/>
+             <xsd:element ref="displaydata"/>
+             <xsd:element ref="comment"/>
+             <xsd:any namespace="##other" processContents="lax"/>
+           </xsd:choice>
+           <xsd:element ref="test" minOccurs="0"
+                        maxOccurs="unbounded"/>
+         </xsd:sequence>
+         <xsd:attribute use="required" name="name" type="identifier"/>
+       </xsd:complexType>
+     </xsd:element>
+
+     <xsd:element name="list">
+       <xsd:complexType>
+         <xsd:sequence>
+           <xsd:element ref="str" minOccurs="1"
+                        maxOccurs="unbounded"/>
+         </xsd:sequence>
+       </xsd:complexType>
+     </xsd:element>
+
+     <xsd:element name="tag" type="identifier"/>
+
+     <xsd:element name="str" type="xsd:string"/>
+
+     <xsd:element name="num" type="xsd:nonNegativeInteger"/>
+
+     <xsd:simpleType name="identifier">
+       <xsd:restriction base="xsd:token">
+         <xsd:pattern value="[A-Za-z_][A-Za-z0-9_]*"/>
+       </xsd:restriction>
+     </xsd:simpleType>
+
+     <xsd:element name="displayblock">
+       <xsd:complexType>
+         <xsd:sequence>
+           <xsd:choice minOccurs="0" maxOccurs="unbounded">
+             <xsd:element ref="control"/>
+             <xsd:element ref="action"/>
+             <xsd:element ref="displayblock"/>
+             <xsd:element ref="displaydata"/>
+             <xsd:element ref="comment"/>
+
+
+
+Freed & Vedam                Standards Track                   [Page 23]
+
+RFC 5784             An XML Representation for Sieve          March 2010
+
+
+             <xsd:any namespace="##other" processContents="lax"/>
+           </xsd:choice>
+         </xsd:sequence>
+         <xsd:anyAttribute processContents="skip"/>
+       </xsd:complexType>
+     </xsd:element>
+
+     <xsd:element name="displaydata">
+       <xsd:complexType>
+         <xsd:sequence minOccurs="0" maxOccurs="unbounded">
+           <xsd:any processContents="skip"/>
+         </xsd:sequence>
+       </xsd:complexType>
+     </xsd:element>
+
+   </xsd:schema>
+
+Appendix C.  Relax NG Schema for Sieves in XML
+
+   This appendix is informative.  The following code component defines a
+   Relax NG Schema using compact notation OASISRNC [OASISRNC] for the
+   XML representation of Sieve scripts.  Most of the elements employing
+   a complex content model allow unrestricted use of elements in other
+   namespaces.  Additionally, displaydata elements can be used to
+   encapsulate arbitrary XML content.  Finally, displayblock elements
+   can be used as a general-purpose grouping mechanism -- arbitrary
+   attributes are allowed on displayblock elements.
+
+   namespace sieve = "urn:ietf:params:xml:ns:sieve"
+
+   start = element sieve:sieve { ( control | action | displayblock |
+                                   displaydata | comment | ext )* }
+
+   comment = element sieve:comment { xsd:string }
+
+   ambles =
+      (
+         ( displaydata | comment | ext )*
+      ),
+      empty
+
+   preamble = element sieve:preamble { ambles }
+   postamble = element sieve:postamble { ambles }
+
+   command =
+      (
+         attribute name {
+           xsd:token {
+
+
+
+Freed & Vedam                Standards Track                   [Page 24]
+
+RFC 5784             An XML Representation for Sieve          March 2010
+
+
+             pattern = "[A-Za-z_][A-Za-z0-9_]*" } },
+         preamble?,
+         ( str | num | \list | tag )*,
+         test?,
+         ( control | action | displayblock)*,
+         postamble?
+      ),
+      empty
+
+   control = element sieve:control { command }
+   action = element sieve:action { command }
+
+   test =
+      element sieve:test
+      {
+         attribute name {
+           xsd:token {
+             pattern = "[A-Za-z_][A-Za-z0-9_]*" } },
+         ( str | num | \list | tag | comment | ext )*,
+         test*
+      }
+
+   \list = element sieve:list { str+ }
+
+   tag = element sieve:tag {
+           xsd:token {
+             pattern = "[A-Za-z_][A-Za-z0-9_]*" } }
+
+   str = element sieve:str { xsd:string }
+
+   num = element sieve:num { xsd:nonNegativeInteger }
+
+   any = ( element * { any } | attribute * { text } | text )*
+
+   ext = element * - sieve:* { any }*
+
+   displayblock =
+      element sieve:displayblock
+      {
+         ( control | action | displayblock |
+           displaydata | comment | ext )*,
+         attribute * { text }*
+      }
+
+   displaydata = element sieve:displaydata { any* }
+
+
+
+
+
+
+Freed & Vedam                Standards Track                   [Page 25]
+
+RFC 5784             An XML Representation for Sieve          March 2010
+
+
+Appendix D.  Stylesheet for Conversion from XML
+
+   This appendix is informative.  The following code component is a
+   stylesheet that can be used to convert the Sieve in XML
+   representation to regular Sieve format.  Content in other namespaces,
+   displaydata, and displayblock elements are converted to structured
+   comments as appropriate.
+
+   <?xml version="1.0" encoding="UTF-8"?>
+
+   <!-- Convert Sieve in XML to standard Sieve syntax -->
+
+   <xsl:stylesheet version="1.0"
+                   xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
+                   xmlns:sieve="urn:ietf:params:xml:ns:sieve">
+
+     <xsl:output method="text" encoding="UTF-8"
+                 media-type="application/sieve"/>
+
+     <!-- Only preserve whitespace in str elements -->
+     <xsl:strip-space elements="*"/>
+     <xsl:preserve-space elements="sieve:str"/>
+
+     <!-- Match top level sieve node,
+          start processing in sieve mode -->
+
+     <xsl:template match="sieve:sieve">
+       <xsl:apply-templates select="*" mode="sieve">
+         <xsl:with-param name="prefix" select="''"/>
+       </xsl:apply-templates>
+     </xsl:template>
+
+     <!-- Routine to properly literalize quotes in Sieve strings -->
+
+     <xsl:template name="quote-string">
+       <xsl:param name="str"/>
+       <xsl:choose>
+         <xsl:when test="not($str)"/>
+         <xsl:when test="contains($str, '&quot;')">
+           <xsl:call-template name="quote-string">
+             <xsl:with-param name="str"
+                select="substring-before($str, '&quot;')"/>
+           </xsl:call-template>
+           <xsl:text>\&quot;</xsl:text>
+           <xsl:call-template name="quote-string">
+             <xsl:with-param name="str"
+                select="substring-after($str, '&quot;')"/>
+           </xsl:call-template>
+
+
+
+Freed & Vedam                Standards Track                   [Page 26]
+
+RFC 5784             An XML Representation for Sieve          March 2010
+
+
+         </xsl:when>
+         <xsl:when test="contains($str, '\')">
+           <xsl:call-template name="quote-string">
+             <xsl:with-param name="str"
+                select="substring-before($str, '\')"/>
+           </xsl:call-template>
+           <xsl:text>\\</xsl:text>
+           <xsl:call-template name="quote-string">
+             <xsl:with-param name="str"
+                select="substring-after($str, '\')"/>
+           </xsl:call-template>
+         </xsl:when>
+         <xsl:otherwise>
+           <xsl:value-of select="$str"/>
+         </xsl:otherwise>
+       </xsl:choose>
+     </xsl:template>
+
+     <!-- Sieve mode processing templates -->
+
+     <xsl:template match="sieve:control|sieve:action" mode="sieve">
+       <xsl:param name="prefix"/>
+       <xsl:text xml:space="preserve">
+   </xsl:text>
+       <xsl:value-of select="$prefix"/>
+       <xsl:value-of select="@name"/>
+       <xsl:variable name="blockbegin"
+               select="generate-id(sieve:control|sieve:action)"/>
+       <xsl:for-each select="*">
+         <xsl:choose>
+           <xsl:when test="self::sieve:str|self::sieve:num|
+                           self::sieve:list|self::sieve:tag|
+                           self::sieve:test">
+             <xsl:apply-templates select="." mode="sieve"/>
+           </xsl:when>
+           <xsl:when test="generate-id(.) = $blockbegin">
+             <xsl:text xml:space="preserve">
+   </xsl:text>
+             <xsl:value-of select="$prefix"/>
+             <xsl:text>{</xsl:text>
+             <xsl:apply-templates select="." mode="sieve">
+               <xsl:with-param name="prefix"
+                  select="concat($prefix, '  ')"/>
+             </xsl:apply-templates>
+           </xsl:when>
+           <xsl:otherwise>
+             <xsl:apply-templates select="." mode="sieve">
+               <xsl:with-param name="prefix"
+
+
+
+Freed & Vedam                Standards Track                   [Page 27]
+
+RFC 5784             An XML Representation for Sieve          March 2010
+
+
+                  select="concat($prefix, '  ')"/>
+             </xsl:apply-templates>
+           </xsl:otherwise>
+         </xsl:choose>
+       </xsl:for-each>
+       <xsl:choose>
+         <xsl:when test="count(sieve:control|sieve:action) &gt; 0">
+           <xsl:text xml:space="preserve">
+   </xsl:text>
+           <xsl:value-of select="$prefix"/>
+           <xsl:text>}</xsl:text>
+         </xsl:when>
+         <xsl:otherwise>
+           <xsl:text>;</xsl:text>
+         </xsl:otherwise>
+       </xsl:choose>
+     </xsl:template>
+
+     <xsl:template match="sieve:preamble|sieve:postamble" mode="sieve">
+       <xsl:param name="prefix"/>
+       <xsl:apply-templates mode="sieve">
+         <xsl:with-param name="prefix" select="$prefix"/>
+       </xsl:apply-templates>
+     </xsl:template>
+
+     <xsl:template match="sieve:test" mode="sieve">
+       <xsl:text xml:space="preserve"> </xsl:text>
+       <xsl:value-of select="@name"/>
+       <xsl:apply-templates select="*[not(self::sieve:test)]"
+                            mode="sieve"/>
+       <xsl:if test="count(descendant::sieve:test) &gt; 0">
+         <xsl:text> (</xsl:text>
+         <xsl:for-each select="sieve:test">
+           <xsl:apply-templates select="." mode="sieve"/>
+           <xsl:if test="count(following-sibling::sieve:test) &gt; 0">
+             <xsl:text>,</xsl:text>
+           </xsl:if>
+         </xsl:for-each>
+         <xsl:text> )</xsl:text>
+       </xsl:if>
+     </xsl:template>
+
+     <xsl:template match="sieve:str" mode="sieve">
+       <xsl:text> &quot;</xsl:text>
+       <xsl:call-template name="quote-string">
+         <xsl:with-param name="str" select="text()"/>
+       </xsl:call-template>
+       <xsl:text>&quot;</xsl:text>
+
+
+
+Freed & Vedam                Standards Track                   [Page 28]
+
+RFC 5784             An XML Representation for Sieve          March 2010
+
+
+     </xsl:template>
+
+     <xsl:template match="sieve:num" mode="sieve">
+       <xsl:text xml:space="preserve"> </xsl:text>
+       <!-- Use numeric suffixes when possible -->
+       <xsl:choose>
+         <xsl:when test="(number(text()) mod 1073741824) = 0">
+           <xsl:value-of select="number(text()) div 1073741824"/>
+           <xsl:text>G</xsl:text>
+         </xsl:when>
+         <xsl:when test="(number(text()) mod 1048576) = 0">
+           <xsl:value-of select="number(text()) div 1048576"/>
+           <xsl:text>M</xsl:text>
+         </xsl:when>
+         <xsl:when test="(number(text()) mod 1024) = 0">
+           <xsl:value-of select="number(text()) div 1024"/>
+           <xsl:text>K</xsl:text>
+         </xsl:when>
+         <xsl:otherwise>
+           <xsl:value-of select="text()"/>
+         </xsl:otherwise>
+       </xsl:choose>
+     </xsl:template>
+
+     <xsl:template match="sieve:list" mode="sieve">
+       <xsl:text> [</xsl:text>
+       <xsl:for-each select="sieve:str">
+         <xsl:apply-templates select="." mode="sieve"/>
+         <xsl:if test="count(following-sibling::sieve:str) &gt; 0">
+           <xsl:text>,</xsl:text>
+         </xsl:if>
+       </xsl:for-each>
+       <xsl:text> ]</xsl:text>
+     </xsl:template>
+
+     <xsl:template match="sieve:tag" mode="sieve">
+       <xsl:text> :</xsl:text>
+       <xsl:value-of select="text()"/>
+     </xsl:template>
+
+     <xsl:template match="sieve:comment" mode="sieve">
+       <xsl:param name="prefix"/>
+       <xsl:text xml:space="preserve">
+   </xsl:text>
+       <xsl:value-of select="$prefix"/>
+       <xsl:text>/*</xsl:text>
+       <xsl:value-of select="."/>
+       <xsl:value-of select="$prefix"/>
+
+
+
+Freed & Vedam                Standards Track                   [Page 29]
+
+RFC 5784             An XML Representation for Sieve          March 2010
+
+
+       <xsl:text>*/</xsl:text>
+     </xsl:template>
+
+     <!-- Convert display information into structured comments -->
+
+     <xsl:template match="sieve:displayblock" mode="sieve">
+       <xsl:param name="prefix"/>
+       <xsl:text xml:space="preserve">
+   </xsl:text>
+       <xsl:value-of select="$prefix"/>
+       <xsl:text>/* [*</xsl:text>
+       <xsl:apply-templates select="@*" mode="copy"/>
+       <xsl:text> */</xsl:text>
+       <xsl:apply-templates select="*" mode="sieve">
+         <xsl:with-param name="prefix" select="$prefix"/>
+       </xsl:apply-templates>
+       <xsl:text xml:space="preserve">
+   </xsl:text>
+       <xsl:value-of select="$prefix"/>
+       <xsl:text>/* *] */</xsl:text>
+     </xsl:template>
+
+     <xsl:template match="sieve:displaydata" mode="sieve">
+       <xsl:param name="prefix"/>
+       <xsl:text xml:space="preserve">
+   </xsl:text>
+       <xsl:value-of select="$prefix"/>
+       <xsl:text>/* [|</xsl:text>
+       <xsl:apply-templates mode="copy">
+         <xsl:with-param name="prefix"
+                         select="concat($prefix, '  ')"/>
+       </xsl:apply-templates>
+       <xsl:text xml:space="preserve">
+   </xsl:text>
+       <xsl:value-of select="$prefix"/>
+       <xsl:text>   |] */</xsl:text>
+     </xsl:template>
+
+     <!-- Copy unrecnognized nodes and their descendants -->
+
+     <xsl:template match="*" mode="sieve">
+       <xsl:param name="prefix"/>
+       <xsl:text xml:space="preserve">
+   </xsl:text>
+       <xsl:value-of select="$prefix"/>
+       <xsl:text>/* [/</xsl:text>
+       <xsl:apply-templates select="." mode="copy">
+         <xsl:with-param name="prefix"
+
+
+
+Freed & Vedam                Standards Track                   [Page 30]
+
+RFC 5784             An XML Representation for Sieve          March 2010
+
+
+                         select="concat($prefix, '  ')"/>
+       </xsl:apply-templates>
+       <xsl:text xml:space="preserve">
+   </xsl:text>
+       <xsl:value-of select="$prefix"/>
+       <xsl:text>   /] */</xsl:text>
+     </xsl:template>
+
+     <!-- Copy mode processing templates -->
+
+     <xsl:template match="*[not(node())]" mode="copy">
+       <xsl:param name="prefix"/>
+       <xsl:text xml:space="preserve">
+   </xsl:text>
+       <xsl:value-of select="$prefix"/>
+       <xsl:text>&lt;</xsl:text>
+       <xsl:value-of select="name()"/>
+       <xsl:apply-templates select="@*" mode="copy"/>
+       <xsl:text>/&gt;</xsl:text>
+     </xsl:template>
+
+     <xsl:template match="*[node()]" mode="copy">
+       <xsl:param name="prefix"/>
+       <xsl:text xml:space="preserve">
+   </xsl:text>
+       <xsl:value-of select="$prefix"/>
+       <xsl:text>&lt;</xsl:text>
+       <xsl:value-of select="name()"/>
+       <xsl:apply-templates select="@*" mode="copy"/>
+       <xsl:text>&gt;</xsl:text>
+       <xsl:apply-templates mode="copy">
+         <xsl:with-param name="prefix"
+                         select="concat($prefix, '  ')"/>
+       </xsl:apply-templates>
+       <xsl:if test="*[last()][not(text())]">
+         <xsl:text xml:space="preserve">
+   </xsl:text>
+         <xsl:value-of select="$prefix"/>
+       </xsl:if>
+       <xsl:text>&lt;/</xsl:text>
+       <xsl:value-of select="name()"/>
+       <xsl:text>&gt;</xsl:text>
+     </xsl:template>
+
+     <xsl:template match="@*" mode="copy">
+       <xsl:text> </xsl:text>
+       <xsl:value-of select="name()"/>
+       <xsl:text>="</xsl:text>
+
+
+
+Freed & Vedam                Standards Track                   [Page 31]
+
+RFC 5784             An XML Representation for Sieve          March 2010
+
+
+       <xsl:value-of select="."/>
+       <xsl:text>"</xsl:text>
+     </xsl:template>
+
+   </xsl:stylesheet>
+
+Appendix E.  Acknowledgements
+
+   The stylesheet copy mode code is loosely based on a sample code
+   posted to the xsl-list list by Americo Albuquerque.  Jari Arkko,
+   Robert Burrell Donkin, Andrew McKeon, Alexey Melnikov, and Aaron
+   Stone provided useful comments on the document.
+
+Authors' Addresses
+
+   Ned Freed
+   Sun Microsystems
+   800 Royal Oaks
+   Monrovia, CA  91016-6347
+   USA
+
+   Phone: +1 909 457 4293
+   EMail: ned.freed@mrochek.com
+
+
+   Srinivas Saisatish Vedam
+   Sun Microsystems
+
+   Phone: +91 80669 27577
+   EMail: Srinivas.Sv@Sun.COM
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Freed & Vedam                Standards Track                   [Page 32]
+