Re: [Boost-users] [Boost.MultiIndex] docs unclear for key extractors

Markus Werle ha escrito:

Hi!

Hello Markus,

In http://boost.org/libs/multi_index/doc/advanced_topics.html #advanced_key_extractors I do not understand how the struct name_extractor comes to use and why I have to define it. IIUC the code snippet -------------------------------- typedef multi_index_container< employee *, indexed_by< ordered_non_unique > >

...

employee_set;

---

takes care of all what I need even without it - or do I have to define the struct to make this work?

This part of the docs is admittedly somewhat confusing. What it tries to convey is that: 1. The concept of key extractor allows for one extractor to work on different types (e.g. the base type and pointers to this), like exemplified by name_extractor. 2. Predefined key extractors take advantage of this circumstance and let you work with pointers and references seamlessly. So, name_extractor just shows how a key extractor can be made to work "polymorphically", but its usage is not exercised at the docs. This is not the first time someone gets puzzled about this particular section, so I tried to improve the docs shipping with Boost 1.34. Please take a look at the new version at: http://boost-consulting.com/boost/libs/multi_index/doc/tutorial/key_extracti... Does it read better now? Best, Joaquín M López Muñoz Telefónica, Investigación y Desarrollo