Re: [boost] [function types][review] (repost with new formatting)

From: Tobias Schwinger (tschwinger_at_[hidden])
Date: 2005-06-14 16:31:20

Paul Mensonides wrote:
>>-----Original Message-----
>>From: boost-bounces_at_[hidden] 
>>[mailto:boost-bounces_at_[hidden]] On Behalf Of Tobias Schwinger
> 
> 
>>>>Only counting "real" parameters here allows us to build 
>>
>>such a cascade 
>>
>>>>for arities ranging from zero to "OUR_MAX_ARITY_LIMIT" 
>>
>>without having 
>>
>>>>to deal with the two special cases that there are no nullary member 
>>>>functions and that we need to go up to OUR_ARITY_LIMIT+1 for member 
>>>>function invocations if the context reference is taken into account.
>>>
>>>
>>>Okay, I've dealt with that issue.  But it's a (really) minor one.
>>>Generating these things with the preprocessor should 
>>
>>usually be done 
>>
>>>with vertical repetition (you'll get lousy compile times and no 
>>>debuggability otherwise), which makes that sort of iteration bounds 
>>>adjustment trivial.
>>>
>>
>>This sounds like using two (slow preprocessor-) loops in 
>>client code for members and non-members, where using one 
>>would be appropriate...
>>
>>I agree it can be "minor", but I currently fail to see it's 
>>"less minor" than your complaint in the first place.
>>
>>
>>I'm having some trouble understanding the second part of the 
>>above paragraph.
>>What could "otherwise" possibly refer to in this context ? 
>>And isn't vertical repetition the slowest form of PP 
>>repetition there is ? Can you perhaps help me with it ?
> 
> 
> Actually, on slow preprocessors vertical repetition is *significantly* faster.
> The only problem is that you cannot entirely encapsulate it in a single macro.
> 

Interesting (depsite the #include)! I like to hear that, since I use it a lot...

> If you show me what you want to generate, I can help you with this.

Well, this was about "what would be helpful in case X"-design-consideration.

However, if you have some (perhaps general) tips for me on how to speed up or 
enhance my preprocessing code it would be great! The BOOST_FT_UNROLL routine at 
the bottom of this [ http://tinyurl.com/d4964 ] file is the heart of any 
preprocessing code in the library, in case you want to take a look.
I just use and trust your library - most of its inside is still pretty much 
black magic to me so the code may be naive (just so you're warned)...

Thanks for offering your help!

Regards,

Tobias