[cfe-dev] override support for Objective-C

[Stuart Carnie]

Hi all,

I would like to have a go at hacking a little on Clang when a get a bit of
spare time, and have found that adding support for override would be useful
little exercise.  I've seen another post referring to Clang's support for
__attribute__((override)), and seems like I could use this as a starting
point.

Big Nerd Ranch <http://weblog.bignerdranch.com/?p=171> would like to see an
@override keyword, as follows:

@override
- (NSInteger)numberOfSectionsInTableview:(UITableView *)tv
{ ... }


This would seem the most natural, but I feel it would involve mucking with
the parser, the AST and therefore fairly complicated.  Given Clang already
parses __attribute__, I could take the following approach instead:

- (NSInteger)numberOfSectionsInTableview:(UITableView *)tv
__attribute__((override))
{ ... }


Can I implement this as a Clang plugin or must I modify Clang source?

One other question is I couldn't get Clang 2.8 to recognize
__has_attribute(override) for a .cpp file:

#ifndef __has_attribute
  #define __has_attribute(x) 0
  #warning no __has_attribute support
#endif

#if __has_attribute(override)
#define OVERRIDE __attribute__((override))
#else
#warning No override attribute
#endif

Would always output the two warnings.

Cheers,

Stu

*Stuart Carnie, CTO*
*manomio <http://manomio.com/> | in retro we trust!*
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