On heap segregation, GC optimization and @nogc relaxing

[deadalnix via Digitalmars-d]

On Thursday, 4 December 2014 at 14:23:13 UTC, Dicebot wrote:
> Finally got a look at your proposal. While I do agree with many 
> initial statements and, specifically, proposal for heap 
> segregation, proposed semantics of `owned` does leave me 
> skeptical. It is effectively a more refined/mature approach to 
> "cooking of immutables" concept and Marc proposal, while being 
> more complicated semantic-wise, allows for much more than that.

I don't think this is solving the same problem as Marc's proposal 
so I'm not sure how comparing them make sense. Marc's proposal is 
about manipulating data without having ownership. This defines 
ownership.

This proposal add some complexity, but I do think this is a 
winner. Right now we have various type qualifier (mutable, const, 
immutable, shared, const shared, inout, inout shared). This come 
at a cost, and, ultimately, as the proposal interact with this, 
you want to compare the total complexity with the total benefit.

In one case, you have 7 qualifier. You get a mostly safe language 
out of them.
With he proposal, you have 8 qualifiers. You get a safe language 
out of it + many opportunities to optimize + added expressiveness 
(ie interaction of GC and no gc code, ownership transfers, safe 
reference counting, extension of possibilities in @nogc code in a 
similar fashion as weakly pure allow for extra expressiveness in 
pure code).

If you allow me for a non politically correct metaphor, would you 
buy a 1$ condom with an hole in it or a 1.14$ one that do not ?