From: Joel de Guzman (joel_at_[hidden])
Date: 2008-01-11 04:48:38
I almost missed Steven's post. Please post to both lists.
Steven Watanabe wrote:
> AMDG
>
> Joel de Guzman <joel <at> boost-consulting.com> writes:
>
>> Single function:
>>
>> I'm a strong advocate of smaller is better. Modularity matters.
>> Big classes (or in this case function objects), metaprogram blobs
>> (i.e. traits), humongous enums, and all such sort of dinosours
>> are best avoided. They are convenient up to a certain extent and
>> becomes unmanageable beyond a certain limit.
>
> When it's being managed by humans sure. When the creation
> of the whatever is automated and it's never used by humans
> directly it doesn't matter much. The big function object
> you refer to has a single conceptual responsibility. It isn't
> a blob any more than a fusion sequence used for the same purpose.
Ok. Good point.
>> In all of my use cases, I have N functions that are provided
>> elsewhere and I have no control over (e.g. parser functions).
>> I insist that this is the more common use case. Grouping
>> them into a single big struct is an unnecessary and cumbersome
>> step.
>
> It may be more common. What I know for certain is that it's
> slightly easier to implement my interface in terms of yours
> than the other way around.
>
>> Still, if people insist, I outlined a way to convert the big
>> function object to smaller 'bound' objects, in another post.
>> Just bind 'em into smaller function chunks.
>
> That's true for your use cases. For cases where
> you have a runtime integer which you need to convert
> into a compile time integer, which is then used to index
> into an mpl sequence for instance (as in variant)
> separate function objects are pointless. I don't want
> to relegate this usage to the side just because you
> don't happen to need it. There are enough use cases
> that it needs to be considered, IMO. Another example is for
> finite state machines. Also, at one point I was considering
> a multiple dispatcher that involved a switch.
Yes. I agree. The index is indeed needed. See my latest posts.
Regards,
-- Joel de Guzman http://www.boost-consulting.com http://spirit.sf.net