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<div class="section" id="limitations">
<h1>Limitations<a class="headerlink" href="#limitations" title="Permalink to this headline">¶</a></h1>
<div class="section" id="things-that-work">
<h2>Things That Work<a class="headerlink" href="#things-that-work" title="Permalink to this headline">¶</a></h2>
<ul class="simple">
<li>Class constants corresponding to string enumeration constraints</li>
<li>Simple and complex type definitions</li>
<li>List and union datatypes</li>
<li>Constraints on (simple) datatypes (e.g., minInclusive, length)</li>
<li>Model groups and attribute groups</li>
<li>Complex content models (all, sequence, choice); minOccurs and maxOccurs</li>
<li>Abstract types, <a class="reference external" href="http://www.w3.org/TR/xmlschema-1/#xsi_type">xsi:type</a>,
substitution groups</li>
<li>Nillable elements with <a class="reference external" href="http://www.w3.org/TR/xmlschema-1/#xsi_nil">xsi:nil</a></li>
<li>Namespace qualified attributes and elements</li>
<li>Documentation annotations present in the schema are converted to Python
docstrings in the generated bindings.</li>
<li>Pattern constraints (as long as the simple type derives from something
that is represented as a Python string)</li>
</ul>
</div>
<div class="section" id="things-that-don-t-work">
<h2>Things That Don’t Work<a class="headerlink" href="#things-that-don-t-work" title="Permalink to this headline">¶</a></h2>
<div class="section" id="but-could-someday">
<h3>...but could someday<a class="headerlink" href="#but-could-someday" title="Permalink to this headline">¶</a></h3>
<ul class="simple">
<li>The ability to use templates to customize binding generation was promised
in the vision document. That has not yet been done, though it should be
fairly straightforward.</li>
<li>Identity constraints (“key”, “unique”, “keyref”) are stored in the content
model, but are not used.</li>
<li><a class="reference external" href="http://www.w3.org/TR/xmlschema-1/#Wildcards">Wildcard elements</a> are
supported in the sense that classes that enable them in the content model
provide access to unrecognized values through the
<a class="reference external" href="api/pyxb.binding.basis.complexTypeDefinition-class.html#wildcardElements">complexTypeDefinition.wildcardElements</a> method.
Where the type of the node is recognized, it is converted to a Python
binding instance; otherwise, the xml DOM instance is stored. Neither the
namespace constraint nor process contents attributes of the wildcard are
applied.</li>
<li><a class="reference external" href="http://www.w3.org/TR/xmlschema-1/#ag-attribute_wildcard">Wildcard attributes</a> are supported
in the same sense as wildcard elements: no constraints are checked, and
all are aggregated into the
<a class="reference external" href="api/pyxb.binding.basis.complexTypeDefinition-class.html#wildcardAttributeMap">complexTypeDefinition.wildcardAttributeMap</a>.
Values are uninterpreted Unicode strings.</li>
</ul>
</div>
<div class="section" id="and-probably-never-will">
<h3>...and probably never will<a class="headerlink" href="#and-probably-never-will" title="Permalink to this headline">¶</a></h3>
<ul class="simple">
<li>When generating a DOM instance from a binding instance, the resulting
document should validate against the schema, but the order of elements
within it may be different from the original order of creation. For an
example of this, see
<tt class="docutils literal"><span class="pre">tests/test-mg-choice:TestMGChoice.testMultichoiceOrderImportant</span></tt>.
See also
<a class="reference external" href="api/pyxb.binding.basis.complexTypeDefinition-class.html#_validatedChildren">complexTypeDefinition._validatedChildren</a> for a
work-around.</li>
<li>The <a class="reference external" href="http://www.w3.org/TR/xmlschema-1/#modify-schema">redefine directive</a>
is not supported.</li>
</ul>
</div>
</div>
<div class="section" id="things-that-mostly-work-but-they-re-ugly">
<h2>Things That Mostly Work, But They’re Ugly<a class="headerlink" href="#things-that-mostly-work-but-they-re-ugly" title="Permalink to this headline">¶</a></h2>
<ul class="simple">
<li>The <a class="reference external" href="http://www.w3.org/TR/xmlschema-2/#duration">duration</a> type is based
on the Python <tt class="docutils literal"><span class="pre">datetime.timedelta</span></tt> class, which works reasonably well
for small deltas but does not handle month and year deltas. The PyXB
version records that information, but the <tt class="docutils literal"><span class="pre">timedelta</span></tt> functionality
(adding/substracting from <tt class="docutils literal"><span class="pre">datetime</span></tt> instances) does not incorporate
that portion of the delta. Negative durations also may not work properly.</li>
</ul>
</div>
<div class="section" id="intended-near-term-enhancements">
<h2>Intended Near-Term Enhancements<a class="headerlink" href="#intended-near-term-enhancements" title="Permalink to this headline">¶</a></h2>
<ul class="simple">
<li>Any requests?</li>
</ul>
</div>
</div>
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<h3><a href="index.html">Table Of Contents</a></h3>
<ul>
<li><a class="reference external" href="#">Limitations</a><ul>
<li><a class="reference external" href="#things-that-work">Things That Work</a></li>
<li><a class="reference external" href="#things-that-don-t-work">Things That Don’t Work</a><ul>
<li><a class="reference external" href="#but-could-someday">...but could someday</a></li>
<li><a class="reference external" href="#and-probably-never-will">...and probably never will</a></li>
</ul>
</li>
<li><a class="reference external" href="#things-that-mostly-work-but-they-re-ugly">Things That Mostly Work, But They’re Ugly</a></li>
<li><a class="reference external" href="#intended-near-term-enhancements">Intended Near-Term Enhancements</a></li>
</ul>
</li>
</ul>
<h4>Previous topic</h4>
<p class="topless"><a href="bundles.html"
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