grauzone: > That's all gone in modern Pascal dialects. Delphi is very similar to D; > it's practically a Pascal version of D. The OOP features are the same, > except for some small differences, which make Delphi a bit more flexible > (virtual and named constructors...).
And as you know, C# was partially designed by the same people :-) About Delphi virtual constructors: http://www.felix-colibri.com/papers/oop_components/delphi_virtual_constructor/delphi_virtual_constructor.html About Delphi named constructors: http://stackoverflow.com/questions/1758917/delphi-pascal-overloading-a-constructor-with-a-different-prototype/1759217#1759217 In Table 2-1 shows a list of some Delphi features: http://oreilly.com/catalog/delphi/chapter/ch02.html Beside virtual methods there are dynamic methods too, that are unrelated to dynamic methods of C#: >Instead of using the virtual directive, you can also use the dynamic >directive. The semantics are identical, but the implementation is different. >Looking up a virtual method in a VMT is fast because the compiler generates an >index directly into a VMT. Looking up a dynamic method is slower. Calling a >dynamic method requires a linear search of a class's dynamic method table >(DMT). If the class does not override that method, the search continues with >the DMT of the base class. The search continues with ancestor classes until >TObject is reached or the method is found. The tradeoff is that in a few >circumstances, dynamic methods take up less memory than virtual methods. >Unless you are writing a replacement for the VCL, you should use virtual >methods, not dynamic methods. See Chapter 3 for a complete explanation of how >dynamic and virtual methods are implemented.< There are even metaclasses (from the same document): >A class, too, is a distinct entity (as in Java, but unlike C++). Delphi's >representation of a class is a read-only table of pointers to virtual methods >and lots of information about the class. A class reference is a pointer to the >table. (Chapter 3, Runtime Type Information, describes in depth the layout of >the class tables.) The most common use for a class reference is to create >objects or to test the type of an object reference, but you can use class >references in many other situations, including passing class references as >routine parameters or returning a class reference from a function. The type of >a class reference is called a metaclass.< In C++/D to do something similar to metaclasses you use templates: http://marcin.wudarczyk.pl/education/tipstricks/metacls.htm > The only thing that was really lacking in Delphi are templates. But for > compensation, it had powerful RTTI. About Delphi RTTI, this document is not new (it seems updated to Delphi 4, that's a bit ancient) but it looks well written: http://www.blong.com/Conferences/BorConUK98/DelphiRTTI/CB140.htm Bye, bearophile
