C# in Depth

Implementingiterators the easy wayThis chapter covers■ Implementing iterators in C# 1■ Iterator blocks in C# 2■■A simple Range typeIterators as coroutinesThe iterator pattern is an example of a behavioral pattern—a design pattern thatsimplifies communication between objects. It’s one of the simplest patterns tounderstand, and incredibly easy to use. In essence, it allows you to access all theelements in a sequence of items without caring about what kind of sequence it is—an array, a list, a linked list, or none of the above. This can be very effective forbuilding a data pipeline, where an item of data enters the pipeline and goes througha number of different transformations or filters before coming out at the otherend. Indeed, this is one of the core patterns of LINQ, as we’ll see in part 3.In .NET, the iterator pattern is encapsulated by the IEnumerator and IEnumerableinterfaces and their generic equivalents. (The naming is unfortunate—the patternis normally called iteration rather than enumeration to avoid getting confused with161Licensed to Rhona Hadida