What's about virtual?

[Joseph Rushton Wakeling]

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.