mydoc_differences.md

title	keywords	last_updated	tags	summary	permalink	folder
Differences to Objective-C 2.0	class	March 26, 2019	language compiler runtime	But how can less be more ? It's impossible! More is more! -- Y. Malmsteen	mydoc_differences.html	mydoc

In terms of language features, mulle_objc resets the basis of Objective-C back to ObjC 1.0 and cherrypicks improvements from the later versions.

Differences to Objective-C 2.0

Do not use the "not planned" features even if the mulle-objc compiler might still understand them. The runtime or the linker will not support them.

Topic	State	Link
@encode()	supported: 90% the same as the Apple runtime	(what is this ?)
@package	never: will produce an error
@synchronized()	not planned	(what is this ?)
**^**blocks	not planned: [^3]	(what is this ?)
atomic	not planned: atomic as default: never
BOOL	supported: but it is an int. If you really need to use bool use _Bool.
@import	not planned	(what is this ?)
nullable	not planned: will produce an error [^2]
readonly	supported: but an ivar will be synthesized
weak, strong	never
__bridge	will be a nop #define (also __bridge_retained, __bridge_transfer)
__unsafe_unretained	could be a nop #define (_autoreleasing)
ARC	never: but look for mulle-objc's AAM	(what is this ?)
@implementation()	never: class extension with added instance variables don't work
NSArray<NSString* >	never: generics are not in the cards	(what is this ?
ObjectiveC++	never: But the mulle-objc instance memory layout should be this->__vtab compatible to allow dual facing objects.
NSArray *foo; foo[ 1]	not planned: [^1] what is known as "Subscripting"	(what is this ?)
Non-fragile ivars	never	(what is this ?)
property dot syntax	not planned: [^1]	(what is this ?)
Protocol	never: Protocol as a class is gone. You have to use PROTOCOL instead of Protocol *
variadic arguments (:...)	supported: but not compatible to <stdarg.h>

---

Appendix

Footnotes

[^1] : This is basically operator overloading, which is un-C like.

[^2] : Superflous keyword, ObjC is by design nullable. It only makes sense to adorn non-nullable parameters.

[^3] : GCD is a Apple technology, that really needs kernel support to work well. lambdas are not a part of C11. Generally I find blocks unconvincing. It might be an idea to make NSInvocations out of block syntax ?

Glossary

Wording	Meaning
not supported	might just accidentally work
not planned	never say never, but this probably won't happen
never	sometimes you have to say never :)

Terminology

For the discussed concepts and terminology check any of the following links.

1. Wikipedia: Objective-C
2. Apple: Objective-C Feature Availability Index
3. NSHipster: @compiler directives

Next

With all the theory under your belt, you're ready to start your own development.