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| <Head> |
| <Title>WritablePropertyMap</Title> |
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| |
| <H2><A NAME="concept:WritablePropertyMap"></A> |
| Writable Property Map |
| </H2> |
| |
| A Writable Property Map has the capability of setting the value |
| object associated with the given key object via the <tt>put()</tt> |
| function. |
| |
| <h3>Refinement of</h3> |
| |
| <a href="../../utility/CopyConstructible.html">Copy Constructible</a> |
| |
| |
| <h3>Notation</h3> |
| |
| <Table> |
| <TR> |
| <TD><tt>PMap</tt></TD> |
| <TD>A type that is a model of Writable Property Map.</TD> |
| </TR> |
| <TR> |
| <TD><tt>pmap</tt></TD> |
| <TD>An object of type <tt>PMap</tt>.</td> |
| </TR> |
| <TR> |
| <TD><tt>key</tt></TD> |
| <TD>An object of type <tt>boost::property_traits<PMap>::key_type</tt>.</td> |
| </TR> |
| <TR> |
| <TD><tt>val</tt></TD> |
| <TD>An object of type <tt>boost::property_traits<PMap>::value_type</tt>.</td> |
| </TR> |
| </table> |
| |
| <h3>Associated Types</h3> |
| |
| <table border> |
| |
| <tr> |
| <td>Value Type</td> |
| <td><TT>boost::property_traits<PMap>::value_type</TT></td> |
| <td> |
| The type of the property. |
| </td> |
| </tr> |
| |
| <tr> |
| <td>Key Type</td> |
| <td><TT>boost::property_traits<PMap>::key_type</TT></td> |
| <td> |
| The type of the key object used to look up the property. The property |
| map may be templated on the key type, in which case this typedef |
| can be <TT>void</TT>. |
| </td> |
| </tr> |
| |
| <tr> |
| <td>Property Map Category </td> |
| <td><TT>boost::property_traits<PMap>::category</TT></td> |
| <td> |
| The category of the property: a type convertible to |
| <TT>writable_property_map_tag</TT>. |
| </td> |
| </tr> |
| |
| </table> |
| |
| |
| <h3>Valid Expressions</h3> |
| |
| <table border> |
| <tr> |
| <th>Name</th><th>Expression</th><th>Return Type</th><th>Description</th> |
| </tr> |
| |
| <tr> |
| <td>Put Property Value<a href="#1">[1]</a></td> |
| <TD><TT>put(pmap, key, val)</TT></TD> |
| <TD><TT>void</TT></TD> |
| <TD> |
| Assign <TT>val</TT> to the property associated with <TT>k</TT>. |
| </TD> |
| </TR> |
| |
| </TABLE> |
| |
| |
| <h3>Notes</h3> |
| |
| <a name="1">[1]</a> The function <tt>put()</tt> was originally named |
| <tt>set()</tt>, but was changed to avoid name conflicts with the |
| <tt>std::set</tt> class when using a compiler (Microsoft Visual C++) |
| with non-standard name lookup rules. The following example demonstrates |
| the problem. |
| <pre>#include <set> |
| using namespace std; |
| namespace boost { |
| void set() { } |
| }</pre> |
| |
| |
| <h3>Concept Checking Class</h3> |
| |
| <pre> template <class PMap, class Key> |
| struct WritablePropertyMapConcept |
| { |
| typedef typename property_traits<PMap>::key_type key_type; |
| typedef typename property_traits<PMap>::category Category; |
| typedef boost::writable_property_map_tag WritableTag; |
| void constraints() { |
| function_requires< ConvertibleConcept<Category, WritableTag> >(); |
| put(pmap, k, val); |
| } |
| PMap pmap; |
| Key k; |
| typename property_traits<PMap>::value_type val; |
| };</pre> |
| |
| <h3>See Also</h3> |
| |
| <a href="./property_map.html">Property map concepts</a> |
| |
| |
| <br> |
| <HR> |
| <TABLE> |
| <TR valign=top> |
| <TD nowrap>Copyright © 2000</TD><TD> |
| <a HREF="http://www.boost.org/people/jeremy_siek.htm">Jeremy Siek</a>, Univ.of Notre Dame (<A HREF="mailto:jsiek@lsc.nd.edu">jsiek@lsc.nd.edu</A>) |
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