Local and Shared

• so far we have assumed basically single-threaded, async execution

• this is most code, but obviously a complete language needs to consider concurrency at a more fundamental level, across threads

• many ways to do this, TS already strongly biases into the "local-first" direction

• we could just generalise SharedArrayBuffer and friends?

• split local and shared memory spaces

• separate heaps, separate GCs

• worker-first, local-first, shared-nothing-first memory model

• local isolated heap per worker

• local and shared modifier on types

• local and shared modifier on bindings

• local and shared modifier on declarations

• worker-local stuff is .. local (Promise, Task, etc.)

• no need for Send and Sync, basically the 90 degree rotated version of that classic pair

• local borrowing managed is sound except across suspension

• how to keep local / shared safe

• proper managed object types on shared

• borrows are place polymorphic by default

• reference types are local by default unless otherwise specified

• SharedSafe