Re:Airbus Chooses GNAT Pro Ada for Development of Unmanned A...
by OneWingedShark on Monday September 21, 2020 @01:58PM
(#24546410)
> Ada seems pretty nice, but it does not have a borrow checker, does it?
IIUC, there is a SPARK implementation that does: https://blog.adacore.com/using-pointers-in-spark / https://www.adacore.com/uploads/techPapers/Safe-Dynamic-Memo...
That said, there are whole classes of problems where, thanks to Ada's design, you don't even NEED pointers where you would in C or similar languages: http://video.fosdem.org/2016/aw1124/memory-management-with-a...
> I think deallocation is considered unsafe? This too depends; Ada was designed so that a garbage-collector could be used, even in Ada83, most implementations do not take advantage of this. (There are JVM and DOTNET implementations where GC is required though.)
To achieve safe deallocation it is often delegated to scopes so that exiting a scope clears out all the memory you were using; see stack-allocation, pools/subpools, and local-declarations/inline-declarations.
Documentation points to [Unchecked_Deallocation](https://docs.adacore.com/live/wave/arm12/html/arm12/arm12-13...) . Rust has automatic (as in, you don't even need to call `free()`), safe deallocation of resources. Of course, the syntax, ergonomics, and the modern looking website and documentation also helped rust become popular, but it is technically new (for a mainstream language).