DTD

The RoadNarrows Document Type Definition for NetMsgs XML is as follows.

<!--
    File: netmsgs.dtd

    $LastChangedDate$
    $Rev$

    This is RoadNarrows LLC NetMsgs DTD, which supports the definitions of
    messages intended to be packed and unpacked in architecture agnostic 
    order and sent and received across a disparate set of networked nodes.

    The NetMsgs package supports the Presentation Level of the OSI model.
    It does not include support to handle the transmission of messages across
    the network nor does it "know" how the applications interpretate the
    messages.

    Typical usage:

    <?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE netmsgs PUBLIC "-//www.roadnarrows.com//DTD NETMSGS 1.0//EN"
          "http://www.roadnarrows.com/DTD/netmsgs/1.0/netmsgs.dtd">
    <netmsgs>
    <meta>
    ...
    </meta>

    <field_types>
    ...
    </field_types>

    <msgdef>
    ...
    </msgdef>

    <msgdef>
    ...
    </msgdef>
    </netmsgs>

    The URI used as a system identifier with the public identifier allows
    the user agent to download the DTD and entity sets as needed.

    This version of the transitional DTD is: 1.0

    Author: Robin Knight (robin.knight@roadnarrows.com)
  
    Copyright:
    (C) 2010.  RoadNarrows LLC.
    (http://www.roadnarrows.com)
    All Rights Reserved

    EULA:
    Permission is hereby granted, without written agreement and without
    license or royalty fees, to use, copy, modify, and distribute this
    software and its documentation for any purpose, provided that
    (1) The above copyright notice and the following two paragraphs
    appear in all copies of the source code and (2) redistributions
    including binaries reproduces these notices in the supporting
    documentation.   Substantial modifications to this software may be
    copyrighted by their authors and need not follow the licensing terms
    described here, provided that the new terms are clearly indicated in
    all files where they apply  
   
    IN NO EVENT SHALL THE AUTHOR, ROADNARROWS LLC, OR ANY MEMBERS/EMPLOYEES
    OF ROADNARROW LLC OR DISTRIBUTORS OF THIS SOFTWARE BE LIABLE TO ANY
    PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL
    DAMAGES ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION,
    EVEN IF THE AUTHORS OR ANY OF THE ABOVE PARTIES HAVE BEEN ADVISED OF
    THE POSSIBILITY OF SUCH DAMAGE  
   
    THE AUTHOR AND ROADNARROWS LLC SPECIFICALLY DISCLAIM ANY WARRANTIES,
    INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
    FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS ON AN
    "AS IS" BASIS, AND THE AUTHORS AND DISTRIBUTORS HAVE NO OBLIGATION TO
    PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
-->

<!-- ==================== Atribute Types =================================== -->
<!ENTITY % MsgEncoding "itv | flat">

<!ENTITY % Endian "big | little | native">

<!ENTITY % Lang "h | c | python">

<!ENTITY % Dispo "active | deprecated">

<!ENTITY % FTypeBuiltInSimple
  "u8 | s8 | char | bool | u16 | s16 | u32 | s32 | u64 | s64 | f32 | f64 |
   p32 | p64"
  >

<!ENTITY % FTypeBuiltInCompound
  "string | struct | vector"
  >

<!ENTITY % FTypeBuiltInAlias
  "byte | schar | ushort | short | uint | int | ulonglong | longlong | 
   float | double"
  >

<!ENTITY % FTypeExtended "CDATA">   <!-- really legal c/python identifier -->

<!ENTITY % FTypeBuiltIn
  "%FTypeBuiltInSimple; | %FTypeBuiltInCompound; | %FTypeBuiltInAlias;"
  >

<!ENTITY % FType "CDATA">   <!-- builtin or extended -->

<!ENTITY % Size "CDATA">    <!-- number or symbol -->


<!-- ==================== Atribute Types =================================== -->
<!ELEMENT netmsgs (meta?, field_types?, msg_types?) >
<!ATTLIST netmsgs
  encoding    (%MsgEncoding;)       "itv"
  endian      (%Endian;)            "big"
  >

<!ELEMENT meta (brief? | ns? | prologue | epilogue)* >
<!ELEMENT brief (#PCDATA) >
<!ELEMENT ns (#PCDATA) >
<!ELEMENT prologue (#PCDATA) >
<!ATTLIST prologue
  lang      (%Lang;)          #REQUIRED
  >
<!ELEMENT epilogue (#PCDATA) >
<!ATTLIST epilogue
  lang      (%Lang;)          #REQUIRED
  >

<!ELEMENT field_types (ftypedef*) >

<!ELEMENT ftypedef (fielddef*) >
<!ATTLIST ftypedef
  ftid    ID                  #REQUIRED
  ftype   %FType;             #REQUIRED
  size    %Size;              #IMPLIED
  >

<!ELEMENT msg_types (msgdef*) >

<!ELEMENT msgdef (fielddef+ | pad* | comment?)* >
<!ATTLIST msgdef
  msgid         ID            #REQUIRED
  disposition   (%Dispo;)     "active"
  >

<!ELEMENT fielddef (const? | min? | max? |  comment? | fielddef?)* >
<!ATTLIST fielddef
  fname         NMTOKEN       #REQUIRED
  ftype         %FType;       #REQUIRED
  size          %Size;        #IMPLIED
  disposition   (%Dispo;)     "active"
  >

<!ELEMENT const (#PCDATA) >
<!ELEMENT min (#PCDATA) >
<!ELEMENT max (#PCDATA) >

<!ELEMENT pad EMPTY >
<!ATTLIST pad
  count   CDATA               #IMPLIED
  >

<!ELEMENT comment (#PCDATA) >