Boost C++ Libraries

...one of the most highly regarded and expertly designed C++ library projects in the world. — Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

Writable Property Map

A Writable Property Map has the capability of setting the value object associated with the given key object via the put() function.

Refinement of

Copy Constructible

Notation

`PMap`	A type that is a model of Writable Property Map.
`pmap`	An object of type `PMap`.
`key`	An object of type `boost::property_traits<PMap>::key_type`.
`val`	An object of type `boost::property_traits<PMap>::value_type`.

Associated Types

Value Type	`boost::property_traits<PMap>::value_type`	The type of the property.
Key Type	`boost::property_traits<PMap>::key_type`	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 `void`.
Property Map Category	`boost::property_traits<PMap>::category`	The category of the property: a type convertible to `writable_property_map_tag`.

Valid Expressions

Name	Expression	Return Type	Description
Put Property Value[1]	`put(pmap, key, val)`	`void`	Assign `val` to the property associated with `k`.

Notes

[1] The function put() was originally named set(), but was changed to avoid name conflicts with the std::set class when using a compiler (Microsoft Visual C++) with non-standard name lookup rules. The following example demonstrates the problem.

#include <set>
using namespace std;
namespace boost {
  void set() { }
}

Concept Checking Class

  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;
  };