Why not flag away the mistakes of the past?

[Jon Degenhardt]

On Wednesday, 7 March 2018 at 06:00:30 UTC, Taylor Hillegeist 
wrote:
> So i've seen on the forum over the years arguments about 
> auto-decoding (mostly) and some other things. Things that have 
> been considered mistakes, and cannot be corrected because of 
> the breaking changes it would create. And I always wonder why 
> not make a solution to the tune of a flag that makes things 
> work as they used too, and make the new behavior default.
>
> dmd --UseAutoDecoding
>
> That way the breaking change was easily fixable, and the 
> mistakes of the past not forever. Is it just the cost of 
> maintenance?

Auto-decoding is a significant issue for the applications I work 
on (search engines). There is a lot of string manipulation in 
these environments, and performance matters. Auto-decoding is a 
meaningful performance hit. Otherwise, Phobos has a very nice 
collection of algorithms for string manipulation. It would be 
great to have a way to turn auto-decoding off in Phobos.

--Jon