What would a minimal subset of D look like?

[Ola Fosheim Grøstad]

On Saturday, 22 June 2019 at 09:25:58 UTC, Yatheendra wrote:
> I'm no embedded programmer, but a possible addition (not 
> removal) might be statically proving bounds safety & 
> reduce/avoid runtime bounds checking on array access; can D or 
> Rust do that? Ada should be able to, with its integer range 
> types. Actually it will have benefits beyond embedded as 
> disabling bounds checking in release builds would no longer be 
> justifiable.

No, D can't. There are languages that can do it, or languages 
with tooling and annotations that can do it.  I believe SPARK 
(derived from Ada) and some C-extension have such tooling 
available.

AFAIK this is generally done by establishing an upper bound on 
the number of iterations you can have in a loop and then 
conceptually "unrolling" the loop up to that point (so that there 
is no for and while, just a long series of if-statements) and 
then using a prover that will then prove that the array bounds 
cannot be exceeded.

It might be possible in some cases for the prover to establish 
this without an upper bound too, but as far as I understand, in 
practice you often have to provide an upper bound.

Ola.