Re: Microsoft is considering moving to Rust; potential opportunity for Ada2020

[Optikos <optikos@verizon.net>]

On Wednesday, July 17, 2019 at 6:35:12 PM UTC-5, Paul Rubin wrote:
> Optikos writes:
> > Yes, I also was wondering why Microsoft isn't fervently exploring
> > adding a Rust-esque borrow checker to C#
> 
> C# is garbage collected, I thought.  No need for anything like a borrow
> checker.

Yes, historically C# is automatic-garbage-collected (AGC), but, to serve as a successor to C & C++ in the development of OS kernel and high-performance services/infrastructure at user-space at Microsoft (or elsewhere), C# would need to trim back any .NET excesses.  AGC is widely perceived (outside of the .NET and JVM communities) as one of those bloated excesses in .NET and in JVM worlds.  One could imagine C# becoming yet another language where AGC is optional, such as via different syntax for introducing AGCed versus borrow-checked modes of operation for each subroutine or each coroutine, operating in the programmer's choice of native or managed (to use Microsoft's terms) or unboxed or boxed (to use other communities' terms), much like C++/WinRT does. (Although in C++/WinRT, the “different syntax” is 1) normal C++ syntax for native versus 2) C++/WinRT's language-projection template(-header-only-library) for managed-via-ATL-to-COM.

Just as an Xlang projection of Rust can wrap C/C++ unsafe legacy code, an Ada language projection in Xlang can bring all that to Ada too, where Ada could also be a memory-safe wrapper language that permits opportunistic rewrite of more & more unsafe guts in the everless-wrapper-veneer evermore-deeper-to-the-core Ada layer.  The Ada language projection in Xlang would mimic the Xlang support for other languages (e.g., Python, Go, Rust) that resemble Ada to greater or lesser degrees.  Indeed, Ada2020 could conceivably most closely mimic Rust support in open-source Xlang to be a fast follower of this Rust experimentation at Microsoft—or at least mimicking Rust support in Xlang closer than any of the further-afield languages such as Python.  Conversely, adding Ada language projections via Xlang would permit Ada to take advantage of the vast forest of Python libraries by invoking them via the Xlang language projection.  Xlang is open-source at GitHub:
https://github.com/Microsoft/xlang