On Sunday, October 16, 2011 19:13:09 Timon Gehr wrote: > I don't agree that 'old' is very difficult to implement. Just evaluate > what is inside the 'old' before you enter the in contract, store > somewhere, maybe in hidden local variables, and make the data available > in the out contract. Eiffel's 'old' does not do more than that. > > (but perhaps there are implementation details in DMD that make this more > difficult than necessary. I don't know.)
What if you're dealing with a class? You'd need to deep copy the entire object for it to work. There's no way built into the language to do that (not to mention that it would be horrifically inefficient). - Jonathan M Davis
