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by touisteur 3332 days ago
Seems AdaCore is working to add some form of borrow-checker to Spark :-) https://cps-vo.org/node/34575
2 comments

In case you're interested, here was a reply from Yannick at AdaCore:

https://groups.google.com/d/msg/comp.lang.ada/H35QcYiWR1Y/jJ...

It seems they're adding a little bit of it for SPARK but not critical, dynamic part. I asked him at the end if they plan to go full, dynamic safety for full Ada if the SPARK experiment succeeds. Awaiting the reply.

Hey thanks for the pointer to this thread. Allowing pointers in SPARK would be incredible... Today SPARK is so interesting because it's not all-or-nothing. So some parts can be SPARK (with different levels of proof), others Ada, etc.

One of the main limitations of the tech is 'no pointers' in SPARK mode. There are some tricks to hide pointers (you may want to look up the SPARK deployment guide : http://www.adacore.com/knowledge/technical-papers/implementa... ) but it would allow so much more code to be SPARK-compatible. Even in the embedded space sometimes you need pointers and linked-lists and hashmaps (and the new formal containers don't do it for you)... Frama-C allows (and seems to work with) pointers, I don't know how Well.

For Ada you can already go a long way (memory safety and data races) with protected object (nice semantics, check performance), not null pointers, controlled-types... But we're far from Rust's borrow-checker and move semantics. The name Unchecked_Deallocation (to instantiate 'Free') says it all.

Can't wait to see some progress on this !

I don't see anything about safety for dynamic, memory management in that link. It just talks about correctness. I'm specifically wanting affine types and ownership system that let SPARK go from static to dynamic.

I do like them splitting it into several levels, though. That worked under Orange Book for security.

My bad, slides are not available yet... There's a mention in there about some rust-like ownership proof mechanism in their roadmap. I thought about our last exchange on SPARK & rust when I saw this :-).
AdaCore hired the guy that designed ParaSail, however the language development is a bit slow.

https://forge.open-do.org/plugins/moinmoin/parasail/FrontPag...

In case you're interested in details on this development:

https://news.ycombinator.com/item?id=14346032