Specification of XDXF Layer 1,  Draft 006

The purpose of the layer 1 is to specify a format into which can be converted all the dictionaries we currently have.
XDXF Layer 1 specifies the base format for all XDXF dictionaries.
Later, more layers will be defined to extend the functionality, but all subsequent layers will comply with all the previous layers specifications.  That is all rules of a certain layer are valid for that layer and all the layers above it.

Each dictionary is located in its own folder, which has the same name as the dictionary.  So, if the dictionary name is "Webster1913" then the folder name and the base name of dictionary files will also be "Webster1913".  Each dictionary shall  have an icon in PNG format with size of 16x16 pixels.  For example:
./xdxf_dictionaries/Webster1913/Webster1913.xdxf
./xdxf_dictionaries/Webster1913/Webster1913.png
Note that the names are case sensitive and the extensions are always lower case.

All XDXF dictionary text files (those with .xdxf extension) are in XML format with UTF-8 encoding.


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XDXF Tags:
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<xdxf>     The root element.
<info>      Information about the dictionary.
<info><lang_from>    ISO 639 three letter code of the language of the key-phrases.
<info><lang_to>        ISO 639 three letter code of the language of the meanings.
<info><type>             Type can be: translation, explanatory, encyclopedia, spelling, audio.
<info><description>  Description of the dictionary in free words.  It is recommended to include the following:
    Copyright, License, From where this file can be downloaded, From where can be downloaded the unformatted
    file, i.e. the original dictionary file before the conversion into XDXF format, From where the original unformatted
    dictionary file was downloaded, Link to the script which was used to convert the original unformatted dictionary file
    into XDXF format.
<abbreviations>    List of abbreviations used in the dictionary.
<abbreviations><item>  Definition of an abbreviation.
<abbreviations><item><key> The abbreviated text.
<abbreviations><item><val>  The full text.
<article>  This tag groups together all the stuff related to one key-phrase.
<article><key>  The key-phrase.  In general, there would be one <key> tag per <articles>, but for some DSL
    dictionaries with nested structure it is necessary to have several keys per article.
<article><def>  This tag marks definition or a group of definitions which fall into a certain category.
                            For English language those categories are parts of speech: noun, verb, adverb, etc.
<article><def lang="xxx"> The optional attribute "lang" specifies the language of translation in ISO 639 three letter
       code if it is different from the <info><lang_to> tag. This is useful only for special dictionaries that provide
       translation into several languages at once.
<article><def><pos>  Tag "pos" specifies the Part Of Speech like: noun, verb, adverb, etc.
<article><def><example>  Marks the text of an example.
<article><def><ref>  Marks reference to another key-phrase in the same dictionary.
<article><def><rref>  Marks reference to a resource of the dictionary which is located in the same folder.
<article><def><rref start="xxx" size="xxx">  Optional attributes are necessary for audio and video files, when the
    reference points to a certain part of a large file.
<article><def><abr>  Marks an abbreviation that is listed in <abbreviations> section.
<article><def><transcription>  Marks transcription
<article><def><color name="...">...</color>  Marks the text with a given color.
<article><def><comment>  Editorial comment.

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Non-XDXF Tags:
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All tags from XHTML Strict are allowed, but for visual marking only.
The programs shell not process those tags but for formatting the text appearance.


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Example:
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<?xml version="1.0" encoding="UTF-8" ?>
<xdxf>
<info>
  <type>meaning</type>
  <lang_from>ENG</lang_from>
  <lang_to>ENG</lang_to>
  <description>Webster's Unabridged Dictionary published 1913 by the  C.  G. Merriam Co...</description>
</info>

<abbreviations>
  <item>  <key>n.</key> <val>noun</val> </item>
  <item>  <key>v.</key> <val>verb</val> </item>
  <item>  <key>Av.</key><key>Ave.</key> <val>Avenue</val> </item>
</abbreviations>

<article>
  <key>record</key>
  <def>
    <pos><abr>n.</abr></pos>
    <transcription>[re'kord]</transcription>
    Anything written down and preserved.
  </def>
  <def>
    <pos><abr>v.</abr></pos>
    <transcription>[reko'rd]</transcription>
    To write down for future use.
  </def>
</article>

<article>
  <key>home</key>
  <transcription>[ho:um]</transcription>
  <def>
    <pos><abr>n.</abr></pos>
    <def> One's own dwelling place; the house in which one lives. </def>
    <def> One's native land; the place or country in which one dwells. </def>
    <def> The abiding place of the affections. <example>For without hearts there is no home.</example> </def>
    See also: <ref> home-made </ref>
  </def>
</article>

<article>
  <key>indices</key> <root_key>index<root_key>
  <def>  Plural form of word "index" </def>
</article>

<article>
  <key>disc</key>
  <key>disk</key>
  <def>
    <pos><abr>n.</abr></pos>
    disc = disk
    A flat, circular plate; as, a disk of metal or paper.
  </def>
</article>
</xdxf>
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Each XDXF dictionary is stored in a ZIP file at http://xdxf.sourceforge.net/TBD.
This will allow programs to download and install dictionaries on the fly.