At this point let me stop talking about details and return to a more abstract description of what we are talking about with those adjusters. On the contrary, with the strategies of AP, by having them as parameters of an adjuster, the collaboration is made explicit - it is directly accessible for the extension programmer and it is maintained automatically, when inheriting from adjusters. Current PLs are good at describing the static interface of an object. Because frameworks are described with PL's, it is hard for developpers to learn the collaborative patterns of a framework by reading it. Instead, they depend on other documentation and talking to experts.
Patterns are one approach to improving the documentation.
But since part of the strength of frameworks is the fact that the framework is expressed in code, it might be better to improve OOPLs so that they can express patterns of collaboration more clearly. If this understanding is correct, then the above paragraph is a perfect expression of what I wanted to say in the part of this mail talking about adjusters vs. application frameworks. Anyway, I will send an email to Ralph in order to be sure I have a correct understanding of what he is saying. A visitor is used in the scope of a strategy. I feel like there is no essential difference.