Why Not All Of The Patterns?
A number of readers have written to ask why I didn’t cover all of the GoF patterns. There really was a number of reasons. Mainly, there just wasn’t room in the book to cover all 23 patterns and also say all of the things about Ruby that I wanted to say.
I also wanted to try to use each pattern as the context
for explaining some aspect of Ruby programming – so
the chapter on the template method pattern talks about
dynamic typing while the chapter on the proxy pattern
method_missing method. But not all of the
GoF patterns are good vehicles for this kind of discussion.
Finally, some of the GoF patterns – and here the visitor pattern comes to mind – just don’t make a lot of sense in Ruby.The missing patterns are: