Dmitry schrieb:

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Dmitry schrieb:

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Jens, the ReadablePropertyMap parameter has to be a class with the following typedef at least:

typedef value_type some_type;

Why?

http://www.boost.org/libs/property_map/ReadablePropertyMap.html says:

Associated Types Value Type boost::property_traits<PMap>::value_type The type of

"Jens Muller" wrote in message news:... the

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property.

That's what these traits classes are for: external adaption.

You replied to the fixed version where I use property_traits.

Jens, I think that you are missing something. As for me, the property_traits class is just a way of uniform data manipulation.

If every pm needed to be a class, there would be no need for the *_traits template classes. http://www.boost.org/libs/graph/doc/leda_conversion.html The Adaptor pattern [12] typically requires that the adaptee object be contained inside a new class that provides the desired interface. This containment is not required when wrapping a graph for BGL because the BGL graph interface consists solely of free (global) functions. Instead of creating a new graph class, you need to overload all the free functions required by the interface. We call this free function wrapper approach external adaptation ... All types associated with a BGL graph class are accessed though the graph_traits class. We can partially specialize this traits class for the LEDA GRAPH class in the following way. The same is done here for vectors and the like.

Your class has to be a model of this abstract concept. (To be a Read Property Map it is enough to have 3 typedefs and get() function, see Concept Checking Class in the documentation that you referred).

Yes, it says the get() free function and 3 typedefs in property_traits need to be defined. Anyway, it works now, see attachments. One question remains, though: template ColorValue MapAsColorMap::get(key_type key) { return (boost::get(pm_, key)==white_) ? boost::color_traits<ColorValue>::white() : boost::color_traits<ColorValue>::black(); } works, while get(pm_, key) without boost:: doesn't. Shouldn't the right get function be found by Koenig lookup? http://www.boost.org/libs/property_map/ReadablePropertyMap.html says, too, that get is required, not boost::get ...