[Boost-commit] svn:boost r85234 - trunk/libs/proto/doc/reference/concepts

Subject: [Boost-commit] svn:boost r85234 - trunk/libs/proto/doc/reference/concepts
From: jhunold_at_[hidden]
Date: 2013-08-07 08:28:01

Author: jhunold
Date: 2013-08-07 08:28:00 EDT (Wed, 07 Aug 2013)
New Revision: 85234
URL: http://svn.boost.org/trac/boost/changeset/85234

Log:
Add missing svn:eol-style to be consistent with the other xml files. Needed for smooth git transition

Properties modified: 
   trunk/libs/proto/doc/reference/concepts/Domain.xml   (contents, props changed)
   trunk/libs/proto/doc/reference/concepts/Expr.xml   (contents, props changed)
Text files modified: 
   trunk/libs/proto/doc/reference/concepts/Domain.xml |   404 ++++++++++++++++++++--------------------
   trunk/libs/proto/doc/reference/concepts/Expr.xml   |   388 +++++++++++++++++++-------------------  
   2 files changed, 396 insertions(+), 396 deletions(-)

Modified: trunk/libs/proto/doc/reference/concepts/Domain.xml
==============================================================================
--- trunk/libs/proto/doc/reference/concepts/Domain.xml	Wed Aug  7 07:12:51 2013	(r85233)
+++ trunk/libs/proto/doc/reference/concepts/Domain.xml	2013-08-07 08:28:00 EDT (Wed, 07 Aug 2013)	(r85234)
@@ -1,202 +1,202 @@
-<?xml version="1.0" ?>
-<!--
-  Copyright 2010 Eric Niebler
-
-  Distributed under the Boost
-  Software License, Version 1.0. (See accompanying
-  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
-  -->
-<concept name="Domain" category="utility">
-  <param name="Domain" role="domain-type" />
-  <param name="Expr" role="expression-type" />
-  <param name="Object" role="object-type" />
-
-  <models-sentence>
-    The type <arg num="1" /> must be a model of <self/>. It also
-    models Unary Polymorphic Function.
-  </models-sentence>
-
-  <models-sentence>
-    The type <arg num="2" /> must be a model of <conceptname>Expr</conceptname>
-  </models-sentence>
-
-  <description>
-    <para>
-      A Domain creates an association between expressions and a so-called
-      generator, which is a function that maps an expression in the default
-      domain to an equivalent expression in this Domain. It also associates
-      an expression with a grammar, to which all expressions within this
-      Domain must conform.
-    </para>
-  </description>
-
-  <notation variables="d">
-    <sample-value>
-      <type name="Domain" />
-    </sample-value>
-  </notation>
-
-  <notation variables="e">
-    <sample-value>
-      <type name="Expr" />
-    </sample-value>
-  </notation>
-
-  <notation variables="o">
-    <sample-value>
-      <type name="Object" />
-    </sample-value>
-  </notation>
-
-  <associated-type name="proto_grammar">
-    <get-member-type name="proto_grammar">
-      <type name="Domain"/>
-    </get-member-type>
-    <description>
-      <simpara>The grammar to which every expression in this Domain
-        must conform.</simpara>
-    </description>
-  </associated-type>
-
-  <associated-type name="proto_generator">
-    <get-member-type name="proto_generator">
-      <type name="Domain"/>
-    </get-member-type>
-    <description>
-      <simpara>
-        A Unary Polymorphic Function that accepts expressions in the
-        default domain and emits expressions in this Domain.
-      </simpara>
-    </description>
-  </associated-type>
-
-  <associated-type name="proto_super_domain">
-    <get-member-type name="proto_super_domain">
-      <type name="Domain"/>
-    </get-member-type>
-    <description>
-      <simpara>
-        The Domain that is a super-domain of this domain, if
-        any such domain exists. If not, it is some unspecified
-        type.
-      </simpara>
-    </description>
-  </associated-type>
-
-  <associated-type name="result_type">
-    <get-member-type name="type">
-      <apply-template name="boost::result_of">
-        <type name="Domain(Expr)"/>
-      </apply-template>
-    </get-member-type>
-    <description>
-      <simpara>
-        The type of the result of applying
-        <computeroutput>proto_generator</computeroutput> to
-        the specified expression type. The result is required to
-        model <conceptname>Expr</conceptname>. The domain type
-        associated with <computeroutput>result_type</computeroutput>
-        (<computeroutput>result_type::proto_domain</computeroutput>)
-        is required to be the same type as this Domain.
-      </simpara>
-    </description>
-  </associated-type>
-
-  <associated-type name="as_expr_result_type">
-    <get-member-type name="result_type">
-      <apply-template name="Domain::as_expr">
-        <type name="Object"/>
-      </apply-template>
-    </get-member-type>
-    <description>
-      <simpara>
-        The result of converting some type to a Proto expression
-        type in this domain. This is used, for instance, when
-        calculating the type of a variable to hold a Proto
-        expression.
-        <computeroutput>as_expr_result_type</computeroutput>
-        models
-        <computeroutput><conceptname>Expr</conceptname></computeroutput>.
-      </simpara>
-    </description>
-  </associated-type>
-
-  <associated-type name="as_child_result_type">
-    <get-member-type name="result_type">
-      <apply-template name="Domain::as_child">
-        <type name="Object"/>
-      </apply-template>
-    </get-member-type>
-    <description>
-      <simpara>
-        The result of converting some type to a Proto expression
-        type in this domain. This is used, for instance, to
-        compute the type of an object suitable for storage
-        as a child in an expression tree.
-        <computeroutput>as_child_result_type</computeroutput>
-        models
-        <computeroutput><conceptname>Expr</conceptname></computeroutput>.
-      </simpara>
-    </description>
-  </associated-type>
-
-  <valid-expression name="Apply Generator">
-    <apply-function name="d">
-      <sample-value>
-        <type name="Expr"/>
-      </sample-value>
-    </apply-function>
-    <return-type>
-      <require-same-type testable="yes">
-        <type name="result_type"/>
-      </require-same-type>
-    </return-type>
-    <semantics>
-      The result of applying <computeroutput>proto_generator</computeroutput>
-      to the specified expression.
-    </semantics>
-  </valid-expression>
-
-  <valid-expression name="As Expression">
-    <apply-function name="Domain::as_expr&lt; Object &gt;()">
-      <sample-value>
-        <type name="Object"/>
-      </sample-value>
-    </apply-function>
-    <return-type>
-      <require-same-type testable="yes">
-        <type name="as_expr_result_type"/>
-      </require-same-type>
-    </return-type>
-    <semantics>
-      The result of converting some object to a Proto expression
-      in this domain. It returns a Proto expression object that
-      is suitable for storage in a variable. It should return a
-      new object, which may be a copy of the object passed in.
-    </semantics>
-  </valid-expression>
-
-  <valid-expression name="As Child">
-    <apply-function name="Domain::as_child&lt; Object &gt;()">
-      <sample-value>
-        <type name="Object"/>
-      </sample-value>
-    </apply-function>
-    <return-type>
-      <require-same-type testable="yes">
-        <type name="as_child_result_type"/>
-      </require-same-type>
-    </return-type>
-    <semantics>
-      The result of converting some object to a Proto expression
-      in this domain. It returns an object suitable for storage
-      as a child in an expression tree, which may simply be a
-      reference to the object passed in.
-    </semantics>
-  </valid-expression>
-
-  <example-model>
-    <type name="boost::proto::default_domain" />
-  </example-model>
-
-</concept>
+<?xml version="1.0" ?>
+<!--
+  Copyright 2010 Eric Niebler
+
+  Distributed under the Boost
+  Software License, Version 1.0. (See accompanying
+  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+  -->
+<concept name="Domain" category="utility">
+  <param name="Domain" role="domain-type" />
+  <param name="Expr" role="expression-type" />
+  <param name="Object" role="object-type" />
+
+  <models-sentence>
+    The type <arg num="1" /> must be a model of <self/>. It also
+    models Unary Polymorphic Function.
+  </models-sentence>
+
+  <models-sentence>
+    The type <arg num="2" /> must be a model of <conceptname>Expr</conceptname>
+  </models-sentence>
+
+  <description>
+    <para>
+      A Domain creates an association between expressions and a so-called
+      generator, which is a function that maps an expression in the default
+      domain to an equivalent expression in this Domain. It also associates
+      an expression with a grammar, to which all expressions within this
+      Domain must conform.
+    </para>
+  </description>
+
+  <notation variables="d">
+    <sample-value>
+      <type name="Domain" />
+    </sample-value>
+  </notation>
+
+  <notation variables="e">
+    <sample-value>
+      <type name="Expr" />
+    </sample-value>
+  </notation>
+
+  <notation variables="o">
+    <sample-value>
+      <type name="Object" />
+    </sample-value>
+  </notation>
+
+  <associated-type name="proto_grammar">
+    <get-member-type name="proto_grammar">
+      <type name="Domain"/>
+    </get-member-type>
+    <description>
+      <simpara>The grammar to which every expression in this Domain
+        must conform.</simpara>
+    </description>
+  </associated-type>
+
+  <associated-type name="proto_generator">
+    <get-member-type name="proto_generator">
+      <type name="Domain"/>
+    </get-member-type>
+    <description>
+      <simpara>
+        A Unary Polymorphic Function that accepts expressions in the
+        default domain and emits expressions in this Domain.
+      </simpara>
+    </description>
+  </associated-type>
+
+  <associated-type name="proto_super_domain">
+    <get-member-type name="proto_super_domain">
+      <type name="Domain"/>
+    </get-member-type>
+    <description>
+      <simpara>
+        The Domain that is a super-domain of this domain, if
+        any such domain exists. If not, it is some unspecified
+        type.
+      </simpara>
+    </description>
+  </associated-type>
+
+  <associated-type name="result_type">
+    <get-member-type name="type">
+      <apply-template name="boost::result_of">
+        <type name="Domain(Expr)"/>
+      </apply-template>
+    </get-member-type>
+    <description>
+      <simpara>
+        The type of the result of applying
+        <computeroutput>proto_generator</computeroutput> to
+        the specified expression type. The result is required to
+        model <conceptname>Expr</conceptname>. The domain type
+        associated with <computeroutput>result_type</computeroutput>
+        (<computeroutput>result_type::proto_domain</computeroutput>)
+        is required to be the same type as this Domain.
+      </simpara>
+    </description>
+  </associated-type>
+
+  <associated-type name="as_expr_result_type">
+    <get-member-type name="result_type">
+      <apply-template name="Domain::as_expr">
+        <type name="Object"/>
+      </apply-template>
+    </get-member-type>
+    <description>
+      <simpara>
+        The result of converting some type to a Proto expression
+        type in this domain. This is used, for instance, when
+        calculating the type of a variable to hold a Proto
+        expression.
+        <computeroutput>as_expr_result_type</computeroutput>
+        models
+        <computeroutput><conceptname>Expr</conceptname></computeroutput>.
+      </simpara>
+    </description>
+  </associated-type>
+
+  <associated-type name="as_child_result_type">
+    <get-member-type name="result_type">
+      <apply-template name="Domain::as_child">
+        <type name="Object"/>
+      </apply-template>
+    </get-member-type>
+    <description>
+      <simpara>
+        The result of converting some type to a Proto expression
+        type in this domain. This is used, for instance, to
+        compute the type of an object suitable for storage
+        as a child in an expression tree.
+        <computeroutput>as_child_result_type</computeroutput>
+        models
+        <computeroutput><conceptname>Expr</conceptname></computeroutput>.
+      </simpara>
+    </description>
+  </associated-type>
+
+  <valid-expression name="Apply Generator">
+    <apply-function name="d">
+      <sample-value>
+        <type name="Expr"/>
+      </sample-value>
+    </apply-function>
+    <return-type>
+      <require-same-type testable="yes">
+        <type name="result_type"/>
+      </require-same-type>
+    </return-type>
+    <semantics>
+      The result of applying <computeroutput>proto_generator</computeroutput>
+      to the specified expression.
+    </semantics>
+  </valid-expression>
+
+  <valid-expression name="As Expression">
+    <apply-function name="Domain::as_expr&lt; Object &gt;()">
+      <sample-value>
+        <type name="Object"/>
+      </sample-value>
+    </apply-function>
+    <return-type>
+      <require-same-type testable="yes">
+        <type name="as_expr_result_type"/>
+      </require-same-type>
+    </return-type>
+    <semantics>
+      The result of converting some object to a Proto expression
+      in this domain. It returns a Proto expression object that
+      is suitable for storage in a variable. It should return a
+      new object, which may be a copy of the object passed in.
+    </semantics>
+  </valid-expression>
+
+  <valid-expression name="As Child">
+    <apply-function name="Domain::as_child&lt; Object &gt;()">
+      <sample-value>
+        <type name="Object"/>
+      </sample-value>
+    </apply-function>
+    <return-type>
+      <require-same-type testable="yes">
+        <type name="as_child_result_type"/>
+      </require-same-type>
+    </return-type>
+    <semantics>
+      The result of converting some object to a Proto expression
+      in this domain. It returns an object suitable for storage
+      as a child in an expression tree, which may simply be a
+      reference to the object passed in.
+    </semantics>
+  </valid-expression>
+
+  <example-model>
+    <type name="boost::proto::default_domain" />
+  </example-model>
+
+</concept>

Modified: trunk/libs/proto/doc/reference/concepts/Expr.xml
==============================================================================
--- trunk/libs/proto/doc/reference/concepts/Expr.xml	Wed Aug  7 07:12:51 2013	(r85233)
+++ trunk/libs/proto/doc/reference/concepts/Expr.xml	2013-08-07 08:28:00 EDT (Wed, 07 Aug 2013)	(r85234)
@@ -1,194 +1,194 @@
-<?xml version="1.0" ?>
-<!--
-  Copyright 2010 Eric Niebler
-
-  Distributed under the Boost
-  Software License, Version 1.0. (See accompanying
-  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
-  -->
-<concept name="Expr" category="utility">
-  <param name="Expr" role="expession-type"/>
-  <param name="Tag" role="tag-type"/>
-  <param name="Domain" role="domain-type"/>
-  <param name="N" role="mpl-integral-constant-type"/>
-
-  <models-sentence>
-    The type <arg num="1"/> must be a model of <self/>.
-  </models-sentence>
-
-  <models-sentence>
-    The type <arg num="3"/> must be a model of <conceptname>Domain</conceptname>.
-  </models-sentence>
-
-  <models-sentence>
-    The type <arg num="4"/> must be a model of MPL Integral Constant.
-  </models-sentence>
-
-  <description>
-    <para>
-      An Expr represents a tagged node in an expression tree.
-      The children of the Expr must themselves satisfy the
-      Expr concept. The Expr has an arity representing the
-      number of children. If the number of children is zero,
-      the Expr also has a value. An Expr also has an associated
-      <conceptname>Domain</conceptname>.
-    </para>
-  </description>
-
-  <notation variables="e">
-    <sample-value>
-      <type name="Expr"/>
-    </sample-value>
-  </notation>
-
-  <associated-type name="proto_tag">
-    <get-member-type name="proto_tag">
-      <type name="Expr"/>
-    </get-member-type>
-    <description>
-      <simpara>The tag type of the Expr.</simpara>
-    </description>
-  </associated-type>
-
-  <associated-type name="proto_args">
-    <get-member-type name="proto_args">
-      <type name="Expr"/>
-    </get-member-type>
-    <description>
-      <simpara>A typelist representing either the types of the child nodes, or,
-        if the arity of the Expr is 0, of the value of the terminal.</simpara>
-    </description>
-  </associated-type>
-
-  <associated-type name="proto_arity">
-    <get-member-type name="proto_arity">
-      <type name="Expr"/>
-    </get-member-type>
-    <description>
-      <simpara>
-        The arity (number of child nodes) of the Expr.
-        <computeroutput>proto_arity</computeroutput> is an MPL Integral Constant.
-      </simpara>
-    </description>
-  </associated-type>
-
-  <associated-type name="proto_grammar">
-    <get-member-type name="proto_grammar">
-      <type name="Expr"/>
-    </get-member-type>
-    <description>
-      <simpara>
-        A typedef for an instantiation of
-        <classname alt="boost::proto::basic_expr">
-          <code>proto::basic_expr&lt;&gt;</code>
-        </classname>
-        that is equivalent to Expr. Expression types are equivalent if they have the
-        same <code>proto_tag</code>, <code>proto_args</code>, and <code>proto_arity</code>.
-      </simpara>
-    </description>
-  </associated-type>
-
-  <associated-type name="proto_base_expr">
-    <get-member-type name="proto_base_expr">
-      <type name="Expr"/>
-    </get-member-type>
-    <description>
-      <simpara>
-        A typedef for an instantiation of
-        <classname alt="boost::proto::expr"><code>proto::expr&lt;&gt;</code></classname> or
-        <classname alt="boost::proto::basic_expr"><code>proto::basic_expr&lt;&gt;</code></classname>
-        that is equivalent to Expr. Expression types are equivalent if they have the
-        same <code>proto_tag</code>, <code>proto_args</code>, and <code>proto_arity</code>.
-      </simpara>
-    </description>
-  </associated-type>
-
-  <associated-type name="proto_derived_expr">
-    <get-member-type name="proto_derived_expr">
-      <type name="Expr"/>
-    </get-member-type>
-    <description>
-      <simpara>
-        A typedef for <code>Expr</code>.
-      </simpara>
-    </description>
-  </associated-type>
-
-  <associated-type name="proto_domain">
-    <get-member-type name="proto_domain">
-      <type name="Expr"/>
-    </get-member-type>
-    <description>
-      <simpara>
-        The Domain of the Expr. <computeroutput>proto_domain</computeroutput>
-        models <conceptname>Domain</conceptname>.
-      </simpara>
-    </description>
-  </associated-type>
-
-  <associated-type name="proto_childN">
-    <get-member-type name="proto_childN">
-      <type name="Expr"/>
-    </get-member-type>
-    <description>
-      <simpara>The type of the Nth child of Expr. Requires 
-        <code>0 == N::value || N::value &lt; proto_arity::value</code></simpara>
-    </description>
-  </associated-type>
-
-  <valid-expression name="Get N-th Child">
-    <apply-function name="boost::proto::child&lt; N &gt;">
-      <sample-value>
-        <type name="Expr"/>
-      </sample-value>
-    </apply-function>
-    <return-type>
-      <require-same-type testable="yes">
-        <type name="proto_childN"/>
-      </require-same-type>
-    </return-type>
-    <semantics>Extracts the Nth child from this Expr.
-      Requires <computeroutput>N::value &lt; proto_arity::value</computeroutput>.</semantics>
-  </valid-expression>
-
-  <valid-expression name="Get Terminal Value">
-    <apply-function name="boost::proto::value">
-      <sample-value>
-        <type name="Expr"/>
-      </sample-value>
-    </apply-function>
-    <return-type>
-      <require-same-type testable="yes">
-        <type name="proto_child0"/>
-      </require-same-type>
-    </return-type>
-    <semantics>
-      Extracts the value from a terminal Expr.
-      Requires <computeroutput>0 == proto_arity::value</computeroutput>.
-    </semantics>
-  </valid-expression>
-
-  <valid-expression name="Get Base">
-    <apply-method name="proto_base">
-      <sample-value>
-        <type name="Expr"/>
-      </sample-value>
-    </apply-method>
-    <return-type>
-      <require-same-type testable="yes">
-        <type name="proto_base_expr"/>
-      </require-same-type>
-    </return-type>
-    <semantics>
-        Returns an object of type
-        <classname alt="boost::proto::expr"><code>proto::expr&lt;&gt;</code></classname> or
-        <classname alt="boost::proto::basic_expr"><code>proto::basic_expr&lt;&gt;</code></classname>
-        that is equivalent to <code>e</code>.
-    </semantics>
-  </valid-expression>
-
-  <example-model>
-    <type name="boost::proto::literal&lt; int &gt;"/>
-  </example-model>
-
-</concept>
+<?xml version="1.0" ?>
+<!--
+  Copyright 2010 Eric Niebler
+
+  Distributed under the Boost
+  Software License, Version 1.0. (See accompanying
+  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+  -->
+<concept name="Expr" category="utility">
+  <param name="Expr" role="expession-type"/>
+  <param name="Tag" role="tag-type"/>
+  <param name="Domain" role="domain-type"/>
+  <param name="N" role="mpl-integral-constant-type"/>
+
+  <models-sentence>
+    The type <arg num="1"/> must be a model of <self/>.
+  </models-sentence>
+
+  <models-sentence>
+    The type <arg num="3"/> must be a model of <conceptname>Domain</conceptname>.
+  </models-sentence>
+
+  <models-sentence>
+    The type <arg num="4"/> must be a model of MPL Integral Constant.
+  </models-sentence>
+
+  <description>
+    <para>
+      An Expr represents a tagged node in an expression tree.
+      The children of the Expr must themselves satisfy the
+      Expr concept. The Expr has an arity representing the
+      number of children. If the number of children is zero,
+      the Expr also has a value. An Expr also has an associated
+      <conceptname>Domain</conceptname>.
+    </para>
+  </description>
+
+  <notation variables="e">
+    <sample-value>
+      <type name="Expr"/>
+    </sample-value>
+  </notation>
+
+  <associated-type name="proto_tag">
+    <get-member-type name="proto_tag">
+      <type name="Expr"/>
+    </get-member-type>
+    <description>
+      <simpara>The tag type of the Expr.</simpara>
+    </description>
+  </associated-type>
+
+  <associated-type name="proto_args">
+    <get-member-type name="proto_args">
+      <type name="Expr"/>
+    </get-member-type>
+    <description>
+      <simpara>A typelist representing either the types of the child nodes, or,
+        if the arity of the Expr is 0, of the value of the terminal.</simpara>
+    </description>
+  </associated-type>
+
+  <associated-type name="proto_arity">
+    <get-member-type name="proto_arity">
+      <type name="Expr"/>
+    </get-member-type>
+    <description>
+      <simpara>
+        The arity (number of child nodes) of the Expr.
+        <computeroutput>proto_arity</computeroutput> is an MPL Integral Constant.
+      </simpara>
+    </description>
+  </associated-type>
+
+  <associated-type name="proto_grammar">
+    <get-member-type name="proto_grammar">
+      <type name="Expr"/>
+    </get-member-type>
+    <description>
+      <simpara>
+        A typedef for an instantiation of
+        <classname alt="boost::proto::basic_expr">
+          <code>proto::basic_expr&lt;&gt;</code>
+        </classname>
+        that is equivalent to Expr. Expression types are equivalent if they have the
+        same <code>proto_tag</code>, <code>proto_args</code>, and <code>proto_arity</code>.
+      </simpara>
+    </description>
+  </associated-type>
+
+  <associated-type name="proto_base_expr">
+    <get-member-type name="proto_base_expr">
+      <type name="Expr"/>
+    </get-member-type>
+    <description>
+      <simpara>
+        A typedef for an instantiation of
+        <classname alt="boost::proto::expr"><code>proto::expr&lt;&gt;</code></classname> or
+        <classname alt="boost::proto::basic_expr"><code>proto::basic_expr&lt;&gt;</code></classname>
+        that is equivalent to Expr. Expression types are equivalent if they have the
+        same <code>proto_tag</code>, <code>proto_args</code>, and <code>proto_arity</code>.
+      </simpara>
+    </description>
+  </associated-type>
+
+  <associated-type name="proto_derived_expr">
+    <get-member-type name="proto_derived_expr">
+      <type name="Expr"/>
+    </get-member-type>
+    <description>
+      <simpara>
+        A typedef for <code>Expr</code>.
+      </simpara>
+    </description>
+  </associated-type>
+
+  <associated-type name="proto_domain">
+    <get-member-type name="proto_domain">
+      <type name="Expr"/>
+    </get-member-type>
+    <description>
+      <simpara>
+        The Domain of the Expr. <computeroutput>proto_domain</computeroutput>
+        models <conceptname>Domain</conceptname>.
+      </simpara>
+    </description>
+  </associated-type>
+
+  <associated-type name="proto_childN">
+    <get-member-type name="proto_childN">
+      <type name="Expr"/>
+    </get-member-type>
+    <description>
+      <simpara>The type of the Nth child of Expr. Requires 
+        <code>0 == N::value || N::value &lt; proto_arity::value</code></simpara>
+    </description>
+  </associated-type>
+
+  <valid-expression name="Get N-th Child">
+    <apply-function name="boost::proto::child&lt; N &gt;">
+      <sample-value>
+        <type name="Expr"/>
+      </sample-value>
+    </apply-function>
+    <return-type>
+      <require-same-type testable="yes">
+        <type name="proto_childN"/>
+      </require-same-type>
+    </return-type>
+    <semantics>Extracts the Nth child from this Expr.
+      Requires <computeroutput>N::value &lt; proto_arity::value</computeroutput>.</semantics>
+  </valid-expression>
+
+  <valid-expression name="Get Terminal Value">
+    <apply-function name="boost::proto::value">
+      <sample-value>
+        <type name="Expr"/>
+      </sample-value>
+    </apply-function>
+    <return-type>
+      <require-same-type testable="yes">
+        <type name="proto_child0"/>
+      </require-same-type>
+    </return-type>
+    <semantics>
+      Extracts the value from a terminal Expr.
+      Requires <computeroutput>0 == proto_arity::value</computeroutput>.
+    </semantics>
+  </valid-expression>
+
+  <valid-expression name="Get Base">
+    <apply-method name="proto_base">
+      <sample-value>
+        <type name="Expr"/>
+      </sample-value>
+    </apply-method>
+    <return-type>
+      <require-same-type testable="yes">
+        <type name="proto_base_expr"/>
+      </require-same-type>
+    </return-type>
+    <semantics>
+        Returns an object of type
+        <classname alt="boost::proto::expr"><code>proto::expr&lt;&gt;</code></classname> or
+        <classname alt="boost::proto::basic_expr"><code>proto::basic_expr&lt;&gt;</code></classname>
+        that is equivalent to <code>e</code>.
+    </semantics>
+  </valid-expression>
+
+  <example-model>
+    <type name="boost::proto::literal&lt; int &gt;"/>
+  </example-model>
+
+</concept>