Comment by ziml77
5 years ago
The boolean issue is probably the one that's caused me the most pain. That contradiction with DRY has actually had me go back and forth between repeating myself and using a flag, wasting a ton of time on something incredibly pointless to be thinking that hard about. I feel like the best thing for my career would have been to not read that book right when I started my first professional programing job.
It's been a while since I've read it, but I think to handle boolean flag type logic well he suggests to rely on object subclassing instead. So, for an example that uses a dry run flag for scary operations, you can have your normal object (a) and all of its methods that actually perform those scary operations. Then you can subclass that object (a) to create a dry run subclass (b). That object b, can override only the methods that perform the scary operations that you want to dry run while at the same time using all of its non scary methods. That would let you avoid having if dry_run == true; then dry_run_method() else scary_method() scattered in lots of different methods.
It might make sense to divide your function with boolean flag into two functions and extract common code into third private function. Or may be it'll make things ugly.
I treat those books as something to show me how other people do things. I learn from it and I add it to my skill book. Then I'll apply it and see if I like it. If I don't like it in this particular case, I'll not apply it. IMO it's all about having insight into every possible solution. If you can implement something 10 different ways, you can choose the best one among them, but you have to learn those 10 different ways first.