Why not abstract policies?
When implementing policies, one needs to follow a specific interface. From what I understand the policies have to be able to replace each other. In modern c++ book, Ch 1.5 3 policies have the same interface "T* Create() {}". Why is there no need to abstract it. It would be important if there are number of interfaces that policies should have. from I understand abstract class gives a recipe for which interfaces should be in concrete classes (the policy classes). In the wikipedia example (http://en.wikipedia.org/wiki/Policy-based_design#Simple_example) "using" defines which interfaces the policy should have but it's not through an abstract class. Isn't the point of abstract class is to make sure that derived classes have the required interfaces?

what am I missing?
Why not abstract policies?
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When implementing policies, one needs to follow a specific interface. From what I understand the policies have to be able to replace each other. In modern c++ book, Ch 1.5 3 policies have the same interface "T* Create() {}". Why is there no need to abstract it. It would be important if there are number of interfaces that policies should have. from I understand abstract class gives a recipe for which interfaces should be in concrete classes (the policy classes). In the wikipedia example (http://en.wikipedia.org/wiki/Policy-based_design#Simple_example) "using" defines which interfaces the policy should have but it's not through an abstract class. Isn't the point of abstract class is to make sure that derived classes have the required interfaces?

what am I missing?