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Newsgroups: comp.lang.ada
Date: Wed, 13 Mar 2019 03:50:28 -0700 (PDT)
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Subject: Re: Intervention needed?
From: Jere <jhb.chat@gmail.com>
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Xref: reader01.eternal-september.org comp.lang.ada:55858
Date: 2019-03-13T03:50:28-07:00
List-Id: <comp.lang.ada>

On Tuesday, March 12, 2019 at 5:53:04 PM UTC-4, Randy Brukardt wrote:
> 
> My understanding is that the SPARK people are far into designing ownership 
> contracts for Spark.
> 
> It's also possible that Ada 2020 will have a form of pointer ownership. 
> (Unfortunately, we didn't make any conclusions on that during yesterday's 
> meeting, so it's still in limbo, and we're getting very close to the finish 
> line.) 

Do you know if either group has been keeping up with the intended
implementations for both SPARK and Ada.  I noticed that from the FOSDEM
video that the SPARK version seemed to mimic the older version of the
Rust ownership/borrow method, but they have since upgraded it.  The 
older Rust version is more flexible than the accessibility levels
that Ada implements for named access types, using scope instead, but
the newer Rust version is "smarter" and actually looks at the actual 
lifetime of the reference instead of just the scope.

See Non-Lexical Lifetimes (odd name for the new system, but whatever):
https://blog.rust-lang.org/2018/12/06/Rust-1.31-and-rust-2018.html#non-lexical-lifetimes