On 6/21/15 8:49 PM, Andrei Alexandrescu wrote:
On 6/21/15 12:31 AM, Edmund Smith wrote:
This idea makes sense with the type checker, although I'm not sure how
it fits D's current memory model. On the page detailing const and
immutable (dlang.org/const3.html) it mentions that immutable data 'can
be placed in ROM (Read Only Memory) or in memory pages marked by the
hardware as read only', which may be problematic if an immutable's
mutable reference counter is placed in a read-only page. Would this
potentially be changed? It suggests that the compiler needs a way of
telling if the struct is a typical immutable struct or is
privately-mutable, publicly-immutable.
Yah, that would need to be changed. That's why we need a way to tell the
typesystem about that kind of data. It can't be put in read-protected
memory of any kind.
Or, use a special value for the reference count that signals ROM.
-Steve
