On Sunday, 6 December 2020 at 11:07:50 UTC, Ola Fosheim Grostad
wrote:
On Sunday, 6 December 2020 at 10:44:39 UTC, Max Haughton wrote:
On Sunday, 6 December 2020 at 05:29:37 UTC, Ola Fosheim
Grostad wrote:
It has to be either some kind of heavily customisable small GC
(i.e. with our resources the GC cannot please everyone), or
arc. The GC as it is just hurts the language.
Realistically, we probably need some kind of working group or
at least serious discussion to really narrow down where to go
in the future. The GC as it is now must go, we need borrowing
to work with more than just pointers, etc.
The issue is that it can't just be done incrementally, it
needs to be specified beforehand.
ARC can be done incrementally, we can do it as a library first
and use a modified version existing GC for detecting failed
borrows at runtime during testing.
But all libraries that use owning pointers need ownership to be
made explicit.
A static borrow checker an ARC optimizer needs a high level IR
though. A lot of work though.
ARC with a library will have overhead unless the compiler/ABI is
changed e.g. unique_ptr in C++ has an indirection.
The AST effectively is a high-level IR. Not a good one, but good
enough. The system Walter has built shows the means are there in
the compiler already.
As things are at the moment, the annotations we have for pointers
like scope go a long way, but the language doesn't deal with
things like borrowing structs (and the contents of structs i.e.
making a safe vector) properly yet. That is what needs thinking
about.
