Re: [boost] Does boost help in creating generic function wrappers?

Subject: Re: [boost] Does boost help in creating generic function wrappers?
From: Andy Venikov (avenikov_at_[hidden])
Date: 2010-07-15 11:07:50

Steven Watanabe wrote:
<snip>
>> functional/forward_adapter won't work since it hides function 
>> parameters, it only lets you operate with the function.
> 
> What do you mean by "hides function parameters"?

Sorry I was unclear.

What I mean was that forward_adapter doesn't let you intercept the 
actual function call. You can store the inner functor in the wrapper 
which allows a delayed call, but whenever someone calls 
wrapper(prms...), you won't have a chance to intercept that call. Of 
course, as you suggest below, one could inject one's own functor in 
between the inner functor and the forward_adapter, but then one is left 
to deal with how to solve forwarding problem on one's own.

> 
>> It looks like it may be possible to do that by using boost/preprocessor
>> I'll have to generate a whole lot of overloads with O(2^N) (because of 
>> the overload on (T &) or (T const &) for every argument).
>> But it looks pretty dounting. It's basically what forward_adapter had 
>> to do.
>>
>> Isn't there a ready-made library that would allow me to generate all 
>> of the overloads?
> 
> Just define your wrapper to take references, and wrap it in 
> forward_adapter.
> This should have exactly the same effect as defining all the overloads
> yourself.

Correct me if I'm wrong, but I think it's not going to work when the 
inner functor has (T const &) parameter. If my wrapper declares 
everything T &, then it won't be able to accept non-const rvalues 
whereas the original functor was able to do that.

> 
> In Christ,
> Steven Watanabe
> 

Thanks,
    Andy.