The Gang of Four’s Design Patterns uses a word processor as an example for at least a few of their patterns, particularly Composite and Flyweight.
Other than by using C or C++, could you really use those patterns and the object-oriented overhead they entail to write a high-performing fully featured word processor?
I know that Eclipse is written in Java but I haven’t used it much so I don’t know if it’s all that fast or as polished as something like Visual Studio, which has a C++ based text editing system.
I only used C++ and Java as examples. The question has more to do with the overhead of having a lot of in-memory objects like you would in an application such as a word processor or even a game.
Design patterns promote abstraction at the expense of parsimony even though they usually point out when you might take some kind of performance hit. Word processors and especially games get the most benefit from being as close to the metal as possible.
I was just wondering if anyone knew of an fast object-oriented word processor or text editor that wasn’t written in C++, and whether they’d build one using patterns or would they forgoe a lot of the abstracting away of things?
Flyweight really is just a way of conserving resources in situations where there are thousands of objects with intrinsic shared state, so it could be useful in higher level languages than C/C++. Maybe the GoF’s example using glyphs in a document was not the best choice to illustrate this pattern.
I think there’s a lot more to building a high performance word processor than just these basic patterns though – not sure whether there is anything in GoF that rules out being able to successfully do this.
Generally, Visual Studio (VS) is more advanced and performs significantly better than Eclipse – at least, the versions of VS that I have seen. Eclipse is one of the most impressive Java applications out there though, it runs quite well on more recent machines with lots of RAM.