On Tuesday, September 10, 2013 18:53:32 Joseph Rushton Wakeling wrote: > On 10/09/13 11:32, Jonathan M Davis wrote: > > AFAIK, no official decision has ever been made. It seemed like Walter was > > convinced that it was worth it to make non-virtual the default, and some > > discussion went into how to do the transition, but I don't believe that > > Andrei has ever liked the idea, and Walter never said that it was > > definitively happening, much as he seemed to have been convinced that it > > should happen. > I seem to recall that the killer argument consisted of 2 parts: > > * Having final-by-default means having speed by default. If people's > default experience is slower than C++, they will not hang around to > work out why or discover that speedups are possible. > > * With final by default, a missing "virtual" on a method can be > corrected without breaking downstream code. By contrast, with virtual by > default, a missing "final" on a method (or whole class) can't be corrected > without a risk of downstream breakage. > > The second was the one that really sold it to me.
What seemed to have convinced Walter was this interview http://www.artima.com/intv/nonvirtualP.html where the focus was on code maintainability and how C#'s approach to virtuality supported code versioning. However, most of the rest of the discussion and what most everyone else was looking for had to do with speed by default. - Jonathan M Davis
