My improvements

[MaddTheSane]

This draft is where I want to push some of the changes that I've implemented in my own fork. Most of these are to increase interoperability with Swift. The first commit was migrating from informal protocols to formal protocols with optionals. This is very much a project that I do want feedback on.

Other planned additions include:

• Migrating to use NS_ENUM/NS_OPTIONS where appropriate.
• Use of NS_TYPED_ENUM/NS_TYPED_EXTENSIBLE_ENUM where appropriate
• Add NSError methods to better work with Swift (My fork wraps the exception-throwing methods, catches the exception, then converts it into an equivalent NSError. A better way would be to migrate as much of the code to use NSErrors only. Relevant code: Link ).
• Rename some enums to better work with Swift.
• Use CommonCrypto where possible.
• Add deprecation markings to symbols (some of this has already been done).
• Use Objective-C 2 @propertys, for-in loops, and @autoreleasepool (this will depend on what other architectures actually support).

A lot of these can be accomplished with using macros on non-Apple platforms (See here for an example).

What I will not (or try not to) do, mainly because the non-Apple runtimes and/or compilers don't support them:

• Migrate project to ARC (To my knowledge, no other target other than Apple's platforms support it).
• Add Swift wrappers for specific functions (This would require a lot of work on editing the makefile).

What needs to be discussed:

• Add generics metadata (Would help with Swift interoperability, but would require either a lot of macros or dropping non-Apple platforms).
• Nullability metadata (would add more analysis to existing code, as well as better Swift interoperability, but might require more macros for non-Apple platforms).