XDXF standand;  Draft 015

The purpose of XDXF standand is to specify an interchange format for free dictionaries.
Later, scripts will be written to convert from different popular formats to XDXF,
then, scripts for convertion from XDXF back to those popular formats,
thus allowing to convert dictionaries from any format to any other.
Also XDXF dictionaries might (and should :) be used directly.

Each dictionary is located in its own folder, the name of the folder is used as the ID.
So, if the dictionary name is "Webster's Unabridged Dictionary published in 1913" then 
the folder name should be something like "Webster1913".  The dictionary file itself is always "dict.xdxf".
It is recommended for each dictionary to have a set of icons for toolbars and a large icon for the front page.
The sizes should be: 16x16, 32x32, 512x512.  And the filenames would be icon16.png icon32.png and 
icon512.png respectively.
Note that all file names are case sensitive.

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.
    The following tags are allowed only in between <info></info> tags.
    <full_name>    Full name of the dictionary, like it would appear on the book cover.  
                              It may contain non-English symbols.
    <lang_from>    ISO 639 three letter code of the language of the key-phrases.
    <lang_to>        ISO 639 three letter code of the language of the meanings.
    <type>             Type can be one or more of the following: translation, explanatory, encyclopedia, spelling,
                             transcription, audio.  If more than one type specified they shall be separated by coma.
    <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.  The description may contain XHTML tags, that are allowed in XDXF and specified below.
    
<abbreviations> section is a list of <abr_def> tags. It describes abbreviations used in the dictionary.
    The <abr_def> tag defines an abbreviation and contains two types of tags:
        <key> The abbreviated text.
        <val>  The full text.
        Note that there may be more than one <key> per <abr_def> to specify synonyms like "Ave." and "Av.",
        but <val> tag can be only one.

<article>  This tag groups together all the stuff related to one key-phrase.
    The following tags are allowed only in between <article></article> tags.
    <key>  The key-phrase.  In general, there would be one <key> tag per <article>. However, some existing
        dictionaries with nested structure have several keys per article, and those <key> tags are interleaved with
        <def> tags.  For new dictionaries, it is recommended to have only one <key> tag per article, except cases when
        the key-phrases are synonyms (like "disc" and "disk") and they are all specified before the first <def> tag.
    <def>  This tag marks a definition or a group of definitions which fall into a certain category.
        For English language those categories could by parts of speech. For example: noun, verb, adverb, etc.
        Note that <def> tags can be nested.  Programs may show them as indented paragraphs in a similar way 
        as C++ programs are indented with curly braces.
        However <def> tag is not mandatory. If the article is simple and there is nothing to group don't use it.
    <pos>  specifies the Part Of Speech like: noun, verb, adverb, etc.
    <tense> The tense. For example: past, present, future, past participle, etc.
    <transcription>  Marks transcription of the key-phrase.
    <dtrn> This tag marks Direct Translation of the key-phrase to another language.
    <kref>  Reference to another key-phrase, which is located in the same file.
    <rref>  Reference to a Resource file, which is located in the same folder.
    <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. The attribute "start" specifies position in the file of the first byte of the
        chunk of interest, and "size" specifies its length in bytes.  If the "start" attribute is omitted then it is assumed
        that it is 0.  If the "size" attribute is omitted then it is assumed that the file should be played up to the end.
    <iref>  Reference to an Internet resource.
    <abr>  Marks an abbreviation that is listed in the <abbreviations> section.
    <color code="xxxxxx">...</color>  Marks text with a given color.  The syntax for "code" attribute is the same as 
        for "color" attribute of "font" tag in HTML.
    <example>  Marks the text of an example. (usually shown in a different color by the program)
    <comment>  Marks the text of an editorial comment. (usually shown in a different color by the program)
    <subarticle> Marks a sub-article. Sub-articles are used to represent nested articles. [TODO: Add more 
        description, and an example]

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Non-XDXF Tags:
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Ideally XDXF would have only the tags that specifies the logical structure of the text and not the appearance.
It would be up to the program to decide how a certain element would look like,
and that appearance would be customizable by the user.
However, in the real world we have dictionaries which already have some visual markings, like <b> and <i>,
and often it is impossible for a converting script to determine with which logical markings they should be substituted.
Therefore, in between the innermost <def></def> tags, the following XHTML tags are allowed for visual marking:
  <br />,  <p>, <sup>, <sub>, <i>, <b>, <tt>, <big>, <small>,  <blockquote>


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

<abbreviations>
  <abr_def><key>n.</key> <val>noun</val></abr_def>
  <abr_def><key>v.</key> <val>verb</val></abr_def>
  <abr_def><key>Av.</key><key>Ave.</key><val>Avenue</val> </abr_def>
</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>
    <rref start="16384" size="512"> sounds_of_words.ogg </rref>
    <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>
    <def> <dtrn>дом</dtrn> at home - дома, у себя; make yourself at home - будьте как дома </def>
    <example>XDXF <b>Home</b> page: <iref> http://xdxf.sourceforge.net </iref></example><br>
    See also: <kref> home-made </kref>
  </def>
</article>

<article>
  <key>indices</key>
  Plural form of word <kref>index</kref>
</article>

<article>
  <key>disc</key>
  <key>disk</key>
  <def>
    <pos><abr>n.</abr></pos>
    A flat, circular plate; as, a disk of metal or paper.
  </def>
</article>
</xdxf>
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* Note: The example has some extra leading spaces and \n symbols. 
They would not be present in a real dictionary file and included are here just for better visualization of the structure.
Otherwise the whole example would have been in one very long line.
Note that \n symbols still can be present freely between articles as they are never sent to the output.