Specification of XDXF Layer 1,  Version 1, Draft 001

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.
The version number represents the release version of the layer specification and ideally should always stay at 1.  The only case when the version number of a certain layer is incremented is when a serious bug is found in the specification after its release to the public.  If we make a change before the public release we increment the draft number.

The intent is to keep XDXF format simple, because if it will be too complicated nobody will use it.
We will not add any feature, unless we really need it.
Don't not say: "Let's add such and such tag, because it might be useful in the future".
Instead, if you have a dictionary with certain features that cannot be converted into current XDXF format, then we will think of something.

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 must  have an icon in PNG format with size of 32x32 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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Tags:
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<xdxf>     The root element.
<info>      Information about the dictionary.
<info><format>    Information necessary for dictionary parsing.
<info><format><layer_number>      XDXF format layer number.
<info><format><layer_version>      Version of the layer. Ideally it should never change.
<info><contents>  Information for the user about the dictionary contents.
<info><contents><type>  Can be either "meaning" or "pronunciation_only".
                                          A dictionary of type "meaning" must have a <def> tag in each <article>.
                                          It also may provide pronunciation.
                                          A dictionary of type "pronunciation_only" should not have any <def> tags at all.
                                          For example a transcription dictionary will have type "pronunciation_only" because it
                                          does not provide any information but pronunciation.

<info><contents><lang_from>    ISO 639 three letter code of the language of the key-phrases.
<info><contents><lang_to>        ISO 639 three letter code of the language of the meanings.
<info><contents><copyright>     Copyright.
<info><contents><license>          License.
<info><contents><description>  Description of the dictionary in free words.
<info><sources>   The origin of the dictionary file.
<info><sources><this_file>  From where this file can be downloaded.
<info><sources><this_file_unformatted> From where can be downloaded the unformatted file, i.e. the
                                                                    original dictionary file before the conversion into XDXF format.
<info><sources><taken_from> From where the original unformatted dictionary file was downloaded.
<info><sources><converter_script_file>  Link to the script which was used to convert the original unformatted
                                                                   dictionary file into XDXF format.
<info><sources><converter_script_ver> The version number of the script mentioned above.
<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.
<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><pos>  Attribute "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><abr>  Marks an abbreviation that is listed in <abbreviations> section.
<article><def><transcription>  Marks transcription


------------------------------------------------------------------------------------
Example:
------------------------------------------------------------------------------------
<?xml version="1.0" encoding="UTF-8" ?>
<xdxf>
<info>
  <format>
    <layer_number>1</layer_number>
    <layer_version>1</layer_version>
  </format>
  <contents>
    <type>meaning</type>
    <lang_from>ENG</lang_from>
    <lang_to>ENG</lang_to>
    <copyright>C. G. Merriam Co. (C)1913 </copyright>
    <license>Public Domain</license>
    <description>Webster's Unabridged Dictionary published 1913 by the  C.  G. Merriam Co.</description>
  </contents>
  <sources>
    <this_file>http://xdxf.sourceforge.net/dicts/Webster1913.xdxf</this_file>
    <this_file_unformatted>="http://xdxf.sourceforge.net/unformatted/Webster1913.ptk"</this_file_unformatted>
    <taken_from>http://www.dict.com/Webster1913.ptk?</taken_from>
    <converter_script_file>http://xdxf.sourceforge.net/scripts/ptk2xdxf.pl</converter_script_file>
    <converter_script_ver>1</converter_script_ver>
  </sources>
</info>

<abbreviations>
  <item>  <key>n.</key> <val>noun</val> </item>
  <item>  <key>v.</key> <val>verb</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>
</xdxf>
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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. That is why we use tags like <def1> and not <font size=3>
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.
Therefor we use several XHTML tags for visual markings:

  <br />,  <p>...</p>
  <sup>...</sup>, <sub>...</sub>, <i>...</i>, <b>...</b>, <tt>...</tt>, <big>...</big>, <small>...</small>
  <font color="...">...</font>



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.