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Purpose
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``dtd2xsc`` is a script that helps create XIST namespace modules from DTDs. It reads one or more DTDs and outputs a skeleton namespace module.


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Options
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``dtd2xsc`` supports the following options:

``urls``
   Zero or more URLs (or filenames) of DTDs to be parsed. If no URL is given stdin will be read.

``-x``, ``--xmlns``
   The default namespace name. All elements that don't belong to any namespace will be assigned to this namespace.

``-s``, ``--shareattrs`` (``none``, ``dupes``, ``all``)
   Should attributes be shared among the elements? ``none`` means that each element will have its own standalone ``Attrs`` class directly derived from ``ll.xist.Elements.Attrs``. For ``dupes`` each attribute that is used by more than one element will be moved into its own ``Attrs`` class. For ``all`` this will be done for all attributes.

``-m``, ``--model`` (``no``, ``simple``, ``fullall``, ``fullonce``)
   Add model information to the namespace. ``no`` doesn't add any model information. ``simple`` only adds ``model = False`` or ``model = True`` (i.e. only the information whether the element must be empty or not). ``fullall`` adds a ``ll.xist.sims`` model object to each element class. ``fullonce`` adds full model information to, but reuses model objects for elements which have the same model.

``-d``, ``--defaults`` (``false``, ``no``, ``0``, ``true``, ``yes`` or ``1``)
   Should default values for attributes specified in the DTD be added to the XIST namespace (as the ``default`` specification in the attribute class)?

``--duplicates`` (``reject``, ``allow``, ``merge``)
   If more that one DTD is specified on the command line, some elements might be specified in more than one DTD. ``--duplicates`` specifies how to handle this case: ``reject`` doesn't allow multiple element specifications. ``allow`` allows them, but only if both specifications are identical (i.e. have the same attributes). ``merge`` allows them and adds the attribute specification of all element specifications to the resulting XIST namespace.

Note that ``dtd2xsc`` requires lxml to work.


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Example
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Suppose we have the following DTD file (named ``foo.dtd``):

   <?xml version="1.0" encoding="ISO-8859-1"?>
   <!ELEMENT persons (person*)>
   <!ELEMENT person (firstname?, lastname?)>
   <!ATTLIST person id CDATA #REQUIRED>
   <!ELEMENT firstname (#PCDATA)>
   <!ELEMENT lastname (#PCDATA)>

Then we can generate a skeleton XIST namespace from it with the following command:

   dtd2xsc ~/gurk.dtd -xhttp://xmlns.example.org/ -mfullall

The output will be:

   # -*- coding: ascii -*-


   from ll.xist import xsc, sims


   xmlns = 'http://xmlns.example.org/'


   class firstname(xsc.Element): xmlns = xmlns


   class lastname(xsc.Element): xmlns = xmlns


   class person(xsc.Element):
      xmlns = xmlns
      class Attrs(xsc.Element.Attrs):
         class id(xsc.TextAttr): required = True


   class persons(xsc.Element): xmlns = xmlns


   person.model = sims.Elements(lastname, firstname)
   persons.model = sims.Elements(person)
   firstname.model = sims.NoElements()
   lastname.model = sims.NoElements()


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def ``getxmlns``​(``dtd``):
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def ``adddtd2xnd``​(``ns``, ``dtd``):
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def ``urls2xnd``​(``urls``, ``shareattrs``=``None``, **``kwargs``):
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def ``main``​(``args``=``None``):
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