Matt Calabrese wrote:
On Tue, May 31, 2011 at 5:21 PM, lcaminiti <lorcaminiti@gmail.com> wrote:
If the return type is a "keyword" known a priori like void then no parenthesis should be needed.
Oh, so you just special-cased some keywords and the rest require parentheses? That's good. The only criticism I have of that is that it's inconsistent. I had some special-casing to eliminate parentheses, similar to what you are doing, but I ultimately sided on being consistent over everything else. That's obviously just my opinion, so I'm not saying you should definitely change it, it's just something to consider.
Yes, I was also concerned about inconsistency so I decided that the syntax will always accept parenthesized types. You can (but don't have to) omit the parenthesis for a known "keyword". This way users can choose as they wish. In other words, the following will both be accepted by the same macros: CONTRACT_FUNCTION( (void) (f)() ) // (1) CONTRACT_FUNCTION( void (f)() ) // (2) If you are worry about consistency, you use (1). If you are worried abut extra parenthesis, you use (2).
Also, given your description (using IS_UNARY), it sounds as though your current implementation cannot handle return types that have top-level commas. For instance, you can't return a boost::array< int, 2 > directly without using a typedef (and if that return type is dependent on the function's template parameters then you could potentially be stuck). I highly recommend that you use variadic macros here to directly check if it's anything parenthesized other than empty. It looks like you're already
Boost.Local's BOOST_IDENTITY_TYPE can be used to handle un-parenthesized commas within macro parameters (see http://svn.boost.org/svn/boost/sandbox/local/boost/utility/identity.hpp).
relying on variadic macros for your parameter lists, so you wouldn't be introducing further compiler requirements.
Similarly to Boost.Local, the syntax will require parenthesis on preprocessors without variadics: CONTRACT_FUNCTION( void (f)( (int x) (int y) ) ... ) // no variadics must use this With variadics, you can still use the above or alternatively the same macros will accept commas: CONTRACT_FUNCTION( void (f)( int x, int y ) ... ) // variadics can (but don't have to) use this
I have done some experimentation that indicates this syntax _should_ be possible but it's not actually implemented yet so... we'll see :)
It's definitely possible, yes.
--Lorenzo -- View this message in context: http://boost.2283326.n4.nabble.com/contract-syntax-redesign-tp3563993p356446... Sent from the Boost - Dev mailing list archive at Nabble.com.