Added Caramel/BoostBook concept documentation (finally)

[SVN r21176]

doc/reference/DefaultConstructible.xml

@@ -0,0 +1,40 @@
+<?xml version="1.0"?>
+<concept name="DefaultConstructible" category="Utility"><!--
+Based on concepts from the SGI Standard Template Library documentation:
+Copyright (c) 1996-1999
+Silicon Graphics Computer Systems, Inc.
+
+Copyright (c) 1994
+Hewlett-Packard Company
+--><!--
+Copyright 2000-2001 University of Notre Dame du Lac.
+Copyright 2001-2002 Indiana University.
+Some concepts based on versions from the MTL draft manual and Boost Graph
+and Property Map documentation:
+Copyright (c) Jeremy Siek, Lie-Quan Lee, and Andrew Lumsdaine 2000
+-->
+  <param name="X" role="default-constructible-type"/>
+
+  <models-sentence>The type <arg num="1"/> must be a model of <self/>.</models-sentence>
+
+  <description><para>DefaultConstructible objects only need to have a default
+  constructor.</para></description>
+
+  <valid-expression name="Construction">
+    <construct template-parameters="">
+      <type name="X"/>
+    </construct>
+    <return-type><require-same-type testable="yes"><type name="X"/></require-same-type></return-type>
+    <semantics>Construct an instance of the type with default parameters.</semantics>
+  </valid-expression>
+
+  <example-model>
+    <type name="int"/>
+  </example-model>
+
+  <example-model>
+    <apply-template name="std::vector">
+      <type name="double"/>
+    </apply-template>
+  </example-model>
+</concept>