 
 
LvaluePropertyMap
The LvaluePropertyMap provides operator[] and function get() for accessing a
reference to a value object. The return type  refines that of function get()in ReadablePropertyMap; it can only be a reference (for a mutable LvaluePropertyMap) or a const reference (for a non-mutable LvaluePropertyMap).
Refinement of
ReadablePropertyMap
for non-mutable or ReadWritePropertyMap for mutable property map.
Notation
| PMap | A type that is a model of LvaluePropertyMap. | 
| pmap | An object of type PMap. | 
| key | An object of type boost::property_traits<PMap>::key_type. | 
Associated Types
| Reference Type | boost::property_traits<PMap>::reference | The reference type, which must be a reference or const reference to
the value type of the property map. | 
| Property Map Category | boost::property_traits<PMap>::category | The category of the property: a type convertible to
boost::lvalue_property_map_tag. | 
Valid Expressions
| Name | Expression | Return Type | Description | 
| Access Property Value | pmap[key] | value_type& for mutable, const value_type&
otherwise. | Obtain a reference to the value associated with key. | 
Concept Checking Class
  template <class PMap, class Key>
  struct LvaluePropertyMapConcept
  {
    typedef typename property_traits<PMap>::category Category;
    typedef boost::lvalue_property_map_tag LvalueTag;
    typedef const typename property_traits<PMap>::value_type& const_reference;
    void constraints() {
      function_requires< ReadWritePropertyMapConcept<PMap, Key> >();
      function_requires< ConvertibleConcept<Category, LvalueTag> >();
      const_reference ref = pmap[k];
    }
    PMap pmap;
    Key k;
  };
  template <class PMap, class Key>
  struct Mutable_LvaluePropertyMapConcept
  {
    typedef typename property_traits<PMap>::category Category;
    typedef boost::lvalue_property_map_tag LvalueTag;
    typedef typename property_traits<PMap>::value_type& reference;
    void constraints() { 
      function_requires< ReadWritePropertyMapConcept<PMap, Key> >();
      function_requires<ConvertibleConcept<Category, LvalueTag> >();
      reference ref = pmap[k];
    }
    PMap pmap;
    Key k;
  };
See Also
Property map concepts