Re: [Boost-users] [preprocessor] Comparing strings in BOOST_PP_NOT_EQUAL

From: Maximilian Matthe (Maxi.Matthe_at_[hidden])
Date: 2008-07-14 15:20:03

Steven Watanabe schrieb:
> AMDG
> 
> Maximilian Matthe wrote:
>> Hi!
>>
>> I'm developing with preprocessor a class generator,
>> that generates the wrapper classes needed by boost.python when
>> you want to derive in python from polymorph c++-base classes.
>>
>> I would need a Macro that expands to "return" if its argument is
>> not void. I tried the following, but that obiously does not work:
>>
>> #define Return(type) \
>>     BOOST_PP_EXPR_IF(BOOST_PP_NOT_EQUAL(type, void), return)
>>
>> I made a workaround by adding an integer value to my Array that
>> defines the methods signature. But that is redundant.
>>
>> Is there a way to achieve the behaviour above?
> 
> It's possible (See BOOST_MPL_PP_TOKEN_EQUAL) but
> it's probably easier to use void returns:
> 
> void f();
> 
> void g() {
>    return f();
> }
> 
> In Christ,
> Steven Watanabe

Thanks for your advice. I'm going to use BOOST_MPL_PP_TOKEN_EQUAL.
Using void returns would result in writing two functions for each
function I want to wrap, so using this macro seems to be a better solution.