Ary Borenszweig: >But if this can't be implemented without compiler support... then it's not of >much use. :-(<
There's another solution: to make D2/D3 itself flexible enough that you can implement your own simple "extensions" to the type system, so you can actually implement not-nullable references by default. This isn't impossible (there are many papers about this, it can be done in Scheme, etc). Once such flexibility is present, you can quickly create such plug-ins to the type system. Like in Firefox, plug-ins are a very good way to experiment new features, that can be later added to the main software if they are good. (Recently GCC has gained the ability to be use plug-ins, but here I am talking about something in the language, not in the compiler). Related: I think the downsides of something like the AST macros (that is community fragmentation, etc) can be quite mitigated if the main purpose of them is to allow to create experimental features that later can be refused or accepted into the official language :-) Bye, bearophile
