Thursday, March 23, 2006

Re: Block Thoughts

Alan Knight posted about More Block Thoughts. He made some excellent points. I particularly loved adding the #collecting:, #selecting, etc protocols on streams.

The funny thing is that the method that I used as an example was part of a larger object that actually was a stream. The stream, named WordStream, wrapped a character stream and returned a Word object on each invocation of #next. Alan mentions that my Word object is "a little bit messier" than strings. And in the context of the single method, I think he is right. But, in the larger context it makes sense. The Word object has a protocol to answer things about the itself like "am I common (the,a,is)?" for example. It's just not a simple wrapper around a String. It's much more.

I love Alan's views on streams, I'm a fan of pipe-filter designs for transformation. The WordStream was simply being fed a character stream to get more meaningful objects out. The users of WordStream only needed to know that it gave them Word objects via the stream protocol. I hate dealing with primitives and the minute I can transform something into a tangible domain object the better.

I feel like I should have given a more thorough example and not one out of context. It would have made the design decision a little more clear. And I could have shown off an example of the pipe-filter pattern. But, I was too thrilled with my new use for blocks.

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