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Merge branch 'michael-schaller-doc-template-nested'

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* michael-schaller-doc-template-nested:
  Nested class template doc tweaks
  Updated C++ template documentation with respect to using a nested class as template parameter.
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William S Fulton 2015-01-16 19:09:00 +00:00
commit 01a6df8aad
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@ -3614,18 +3614,52 @@ and the second will take two integer arguments.
</p> </p>
<p> <p>
Needless to say, SWIG's template support provides plenty of Needless to say, SWIG's template support provides plenty of opportunities to
opportunities to break the universe. That said, an important final break the universe. That said, an important final point is that <b>SWIG does
point is that <b>SWIG does not perform extensive error checking of not perform extensive error checking of templates!</b> Specifically, SWIG does
templates!</b> Specifically, SWIG does not perform type checking nor not perform type checking nor does it check to see if the actual contents of the
does it check to see if the actual contents of the template template declaration make any sense. Since the C++ compiler checks this when it
declaration make any sense. Since the C++ compiler will hopefully compiles the resulting wrapper file, there is no practical reason for SWIG to
check this when it compiles the resulting wrapper file, there is no duplicate this functionality.
practical reason for SWIG to duplicate this functionality (besides,
none of the SWIG developers are masochistic enough to want to
implement this right now).
</p> </p>
<a name="SWIGPlus_template_nested_class_example"></a>
<p>
As SWIG's template support does not perform type checking <tt>%template</tt>
can be used as early as after a template declaration. You can, and rarely have
to, use <tt>%template</tt> before the template parameters have been declared.
For example:
</p>
<div class="code">
<pre>
template &lt;class T&gt; class OuterTemplateClass {};
// The nested class OuterClass::InnerClass inherits from the template class
// OuterTemplateClass&lt;OuterClass::InnerStruct&gt; and thus the template needs
// to be expanded with %template before the OuterClass declaration.
%template(OuterTemplateClass_OuterClass__InnerStruct)
OuterTemplateClass&lt;OuterClass::InnerStruct&gt;
// Don't forget to use %feature("flatnested") for OuterClass::InnerStruct and
// OuterClass::InnerClass if the target language doesn't support nested classes.
class OuterClass {
public:
// Forward declarations:
struct InnerStruct;
class InnerClass;
};
struct OuterClass::InnerStruct {};
// Expanding the template at this point with %template is too late as the
// OuterClass::InnerClass declaration is processed inside OuterClass.
class OuterClass::InnerClass : public OuterTemplateClass&lt;InnerStruct&gt; {};
</pre>
</div>
<p> <p>
<b>Compatibility Note</b>: The first implementation of template support relied heavily on <b>Compatibility Note</b>: The first implementation of template support relied heavily on
macro expansion in the preprocessor. Templates have been more tightly integrated into macro expansion in the preprocessor. Templates have been more tightly integrated into
@ -5000,6 +5034,12 @@ class Bar {
</pre> </pre>
</div> </div>
<p>
If a nested class, within an outer class, has to be used as a template parameter within the outer class, then the template will
have to be instantiated with <tt>%template</tt> before the beginning of the outer class.
An example can be found in the
<a href="#SWIGPlus_template_nested_class_example">Templates</a> section.
</p>
<p> <p>
<b>Compatibility Note:</b> <b>Compatibility Note:</b>