dtd2xsc – Creating XIST namespaces from DTDs

Purpose

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

Options

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 <name>, --xmlns <name>

The default namespace name. All elements that don’t belong to any namespace will be assigned to this namespace.

-s <value>, --shareattrs <value>

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 <value>, --model <value>

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 <flag>, --defaults <flag>

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

--duplicates <value>

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.

Example

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()