On Monday, May 14, 2012 17:10:23 Roman D. Boiko wrote: > (Subj.) I'm in doubt which to choose for my case, but this is a > generic question. > > http://forum.dlang.org/post/odcrgqxoldrktdtar...@forum.dlang.org > > Cross-posting here. I would appreciate any feedback. (Whether to > reply in this or that thread is up to you.) Thanks
For the question in general, there are primarily 2 questions to consider: 1. Do you need inheritance/polymorphism? 2. Do you need a value type or a reference type? If you need inheritance/polymorphism, you have to use classes, because structs don't have inheritance. If you want a value type, you have to use structs, because classes are reference types. If you want a reference type, then you can use either a class or a struct, but it's easier with classes, because classes are always reference types, whereas structs are naturally value types, so it can take more work to make them reference types depending on what its member variables are. One other thing to consider is deterministic destruction. The only way to get deterministic destruction is to have a struct on the stack. Value types will naturally get that, but if you want a reference type with determinstic destruction, then you're probably going to have to use a ref-counted struct. In the vast majority of cases, that should be enough to decide whether you need a class or a struct. The main case that it doesn't is the case where you want a reference type and don't necessarily want a class, and that decision can get complicated. In the case of a token in a lexer, I would definitely expect that to be a value type, which means using a struct. - Jonathan M Davis