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| <a name="ObjectTransform"></a><div class="titlepage"></div> |
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| <h2><span class="refentrytitle">Concept ObjectTransform</span></h2> |
| <p>ObjectTransform</p> |
| </div> |
| <div class="refsect1"> |
| <a name="id2457141"></a><h2>Description</h2> |
| <p> |
| An ObjectTransform is a function type or a function |
| pointer type where the return type Obj is a |
| an object type and the arguments are |
| Transforms. is_callable< Obj >::value |
| must be false. The ObjectTransform, when applied, |
| has the effect of constructing an object of type |
| Obj' (see below), passing as construction parameters |
| the result(s) of applying transform(s) Tn. |
| </p> |
| <p> |
| The type Obj may be a template specialization representing |
| a compile-time lambda expression. For instance, if Obj is |
| std::pair< proto::_value, int >, the result type of the |
| ObjectTransform is computed by replacing the type proto::_value |
| with the result of applying the proto::_value transform. For |
| given types Obj, Expr, State and Data, we can say that the |
| type Obj' represents the type Obj after all nested transforms |
| have been replaced with the results of applying the transforms |
| with Expr, State and Data as transform arguments. |
| </p> |
| <p> |
| If the type Obj is not a template specialization representing |
| a compile-time lambda expression, then the result type Obj' is |
| the same as Obj. |
| </p> |
| </div> |
| <div class="refsect1"> |
| <a name="id2457161"></a><h2>Notation</h2> |
| <div class="variablelist"><dl> |
| <dt><span class="term">Obj</span></dt> |
| <dd>A type playing the role of object-type in the <a class="link" href="ObjectTransform.html" title="Concept ObjectTransform">ObjectTransform</a> concept.</dd> |
| <dt><span class="term">Tn</span></dt> |
| <dd>A type playing the role of transform-type in the <a class="link" href="ObjectTransform.html" title="Concept ObjectTransform">ObjectTransform</a> concept.</dd> |
| <dt><span class="term">Expr</span></dt> |
| <dd>A type playing the role of expression-type in the <a class="link" href="ObjectTransform.html" title="Concept ObjectTransform">ObjectTransform</a> concept.</dd> |
| <dt><span class="term">State</span></dt> |
| <dd>A type playing the role of state-type in the <a class="link" href="ObjectTransform.html" title="Concept ObjectTransform">ObjectTransform</a> concept.</dd> |
| <dt><span class="term">Data</span></dt> |
| <dd>A type playing the role of data-type in the <a class="link" href="ObjectTransform.html" title="Concept ObjectTransform">ObjectTransform</a> concept.</dd> |
| <dt><span class="term"><code class="varname">expr</code></span></dt> |
| <dd>Object of type Expr</dd> |
| <dt><span class="term"><code class="varname">state</code></span></dt> |
| <dd>Object of type State</dd> |
| <dt><span class="term"><code class="varname">data</code></span></dt> |
| <dd>Object of type Data</dd> |
| </dl></div> |
| </div> |
| <div class="refsect1"> |
| <a name="id2457260"></a><h2>Valid expressions</h2> |
| <div class="informaltable"><table class="table"> |
| <colgroup> |
| <col> |
| <col> |
| <col> |
| <col> |
| </colgroup> |
| <thead><tr> |
| <th>Name</th> |
| <th>Expression</th> |
| <th>Type</th> |
| <th>Semantics</th> |
| </tr></thead> |
| <tbody><tr> |
| <td><p>Apply Transform</p></td> |
| <td><p>when< _, Obj(Tn...)>()(expr, state, data)</p></td> |
| <td><p><span class="type">Obj'</span></p></td> |
| <td><p>Applies the transform.</p></td> |
| </tr></tbody> |
| </table></div> |
| </div> |
| <div class="refsect1"> |
| <a name="id2457297"></a><h2>Models</h2> |
| <div class="itemizedlist"><ul class="itemizedlist" type="disc"><li class="listitem"><span class="simplelist"><span class="type">std::pair< boost::proto::_value, int >(boost::proto::_value, int())</span></span></li></ul></div> |
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| <td align="left"></td> |
| <td align="right"><div class="copyright-footer">Copyright © 2008 Eric Niebler<p> |
| Distributed under the Boost Software License, Version 1.0. (See accompanying |
| file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>) |
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