On Monday, 25 August 2014 at 15:09:32 UTC, bearophile wrote:
Marc Schütz:
http://wiki.dlang.org/User:Schuetzm/scope
It looks nice. But perhaps it needs some kind of proof of
correctness.
Hmm... First there's the assignment rules. They make sure that
nothing with a shorter lifetime ends up in a variable with a
longer lifetime designation. The other part is to proof that the
type deduction and argument matching rules work.
Both parts are not difficult to reason about, but I don't know
what a formal proof needs to look like exactly. (How formal do we
need to go?)
Have you read the old blog posts (written before the creation
of Rust) by Bartosz Milewski regarding the borrowing in D?
No, can you point me to them? I couldn't find them on his blog
under http://bartoszmilewski.com/category/d-programming-language/
There are some posts about ownership and regions, but only in the
context of multi-threading. I'm afraid this wouldn't easily fit
into a hierarchical system like I have in mind.
Implementation of this feature is possible without doing flow
control or interprocedural analysis.<
I remember that Walter has recently said that he's willing to
add some kind of flow analysis to the D front-end.
Interesting. The question is: is it worth it? Maybe we can
already cover 99% of the use cases with a simpler construct. The
concept needs to be understandable for the users of the language,
too. And maybe "some kind of flow analysis" just isn't enough to
get a significant improvement, maybe it would need whole-program
analysis...
