Re: [Boost-users] Limits in MPL and Fusion - bad doc, not checked, could be extended

Subject: Re: [Boost-users] Limits in MPL and Fusion - bad doc, not checked, could be extended
From: Lars Viklund (zao_at_[hidden])
Date: 2011-11-09 02:47:16

On Tue, Nov 08, 2011 at 08:42:40PM +0100, Hite, Christopher wrote:
> /fs/tools/L3/boost_1_43_0/boost/mpl/list.hpp:36:69: fatal error: boost/mpl/list/list80.hpp: No such file or directory
> BOOST_MPL_CFG_NO_PREPROCESSED_HEADERS doesn't seem to work if you read the documentation.  The doc should say "we have a hard coded limit of 50".
> 
> /fs/tools/L3/boost_1_43_0/boost/fusion/container/vector/detail/vector_n_chooser.hpp:45:1: error: 'vector80' does not name a type
> fusion is even worse.  It could easily checks FUSION_MAX_VECTOR_SIZE in vector_n_chooser.hpp, but doesn't detect a value that's too big.
> 
> 1) I think both test libraries should #error if you go over the limit.
> 
> 2) Why don't we extend the limits?
> I may wind up doing this real quick to keep my code working (needs 71).  Can I merge the changes into trunk when I'm done and after 1.48 is finished?

I believe that for most libraries, there's a non-trivial increase in
compile-time for any user of the library when you increase the arity of
things.

Bumping up the default could have rather adverse effects on the compile
time of people who doesn't want to pay for it.

-- 
Lars Viklund | zao_at_[hidden]