Optimizing Java using D

[Chris Cain via Digitalmars-d]

On Monday, 23 June 2014 at 17:26:47 UTC, Andrei Alexandrescu 
wrote:
> Corollary: the default sorting algorithm in std will always be 
> unstable, even if for certain data types and inputs it will 
> produce stable sorting. -- Andrei

I'd also like to note that this whole discussion about 
restrictions and such can also be shown as an argument for why 
stable sort should be the default. That is, we can prove that 
with the restriction of stability that if an unstable sort will 
give you suitable results then a stable sort will also give you 
suitable results, but the reverse is not true.

That is, if you don't know whether relaxing the stability 
requirement of the sort will give you "wrong answers" on some 
inputs of your programs, sorting using a stable sort is the 
correct choice. You need to have a reason to relax that 
requirement before doing it.

Speed is an OK argument for choosing unstable sort as default, 
but I think stronger guarantees that it will produce a correct 
output for a general problem is a better argument. Relaxation of 
guarantees should be an opt-in decision by a programmer only when 
they know the difference doesn't matter to the problem. This sort 
of logic is consistent with decisions made in the past about the 
direction of D.