Generic Component: Views ...

• View type V_rec, which wraps T_rec and defines M_acc, C₀, and the name of V_item. V_rec lists myadder as a superclass so that it inherits generics that do the work of sum.

• T_item, type of the item from with the summand is derived.

• A mapping M_item: T_item &rarr T_acc that specifies how to obtain the data to be summed from each item of type T_item.

• A predicate P_item: T_item &rarr {T,F} that determines whether an item should be summed. P_item defaults to T.

• View type V_item, which wraps T_item and defines M_item and P_item.

Clearly, it is necessary to produce most of this automatically, or the component will be too hard to reuse.

Contents    Page-10    Prev    Next    Page+10    Index