This page is a snapshot from the LWG issues list, see the Library Active Issues List for more information and the meaning of NAD Concepts status.
Section: 24.7 [rand] Status: NAD Concepts Submitter: Alisdair Meredith Opened: 2009-03-12 Last modified: 2016-12-23
Priority: Not Prioritized
View all other issues in [rand].
View all issues with NAD Concepts status.
The RandomNumberEngineAdaptor concept breaks precedent in the way the library has been specified by grouping requirements into a concept that is never actually used in the library.
This is undoubtedly a very helpful device for documentation, but we are not comfortable with the precedent - especially as we have rejected national body comments on the same grounds.
Suggest either removing the concept, or providing an algorithm/type that requires this concept in their definition (such as a factory function to create new engines).
The preference is to create a single new algorithm and retain the value of the existing documentation.
[ Batavia (2009-05): ]
Walter points out that it is unlikely that any algorithm would ever require this concept, but that the concept nonetheless is useful as documentation, and (via concept maps) as a means of checking specific adapters.
Alisdair disagrees as to the concept's value as documentation.
Marc points out that the RandomNumberDistribution is also a concept not used elsewhere in the Standard.
Pete agrees that a policy of not inventing concepts that aren't used in the Standard is a good starting point, but should not be used as a criterion for rejecting a concept.
Move to Open.