On 2014-04-18 20:40:06 +0000, Walter Bright <newshou...@digitalmars.com> said:
O-C doesn't use ARC for all pointers, nor is it memory safe.
@safe would be very easy to implement in Objective-C now that ARC is there.
This has got me thinking. Ever heard "C is the new assembly"? I think
this describes very well the relation between C and Objective-C in most
Objective-C programs today.
Objective-C enables ARC by default for all pointers to Objective-C
objects. Since virtually all Objective-C APIs deal with Objective-C
objects (or integral values), if you limit yourself to Objective-C APIs
you're pretty much memory-safe.
When most people write Objective-C programs, they use exclusively
Objective-C APIs (that deal with Objective-C objects and integrals,
thus memory-safe), except for the few places where performance is
important (tight loops, specialized data structures) or where
Objective-C APIs are not available.
You can mix and match C and Objective-C code, so no clear boundary
separates the two, but that doesn't mean there couldn't be one. Adding
a @safe function attribute to Objective-C that'd prevent you from
touching a non-managed pointer is clearly something I'd like to see in
Objective-C. Most Objective-C code I know could already be labeled
@safe with no change. Only a small fraction would have to be updated or
left unsafe.
Silly me, here I am discussing a improvement proposal for Objective-C
in a D forum!
The point being, D could have managed and unmanaged pointers (like
Objective-C with ARC has), make managed pointers the default, and let
people escape pointer management if they want to inside
@system/@trusted functions. One way it could be done is by tagging
specific pointers with some attribute to make them explicitly not
managed (what __unsafe_unretained is for in Objective-C). Perhaps the
whole function could be tagged too. But you won't need this in general,
only when optimizing a tight loop or something similar where
performance really counts.
Whether that's the path D should take, I don't know.
--
Michel Fortin
michel.for...@michelf.ca
http://michelf.ca
