Re: [boost] Array support [was SmartPtr (Loki) - auto_ptr/move c'tor issue]

From: Beman Dawes (bdawes_at_[hidden])
Date: 2003-02-03 16:25:20

At 02:32 PM 2/3/2003, Howard Hinnant wrote:

 >On Monday, February 3, 2003, at 12:50  PM, Beman Dawes wrote:

 >> To me, a major benefit of a policy based design is to be able to
 >> accommodate a wide range of features, including those which find only
 >> limited use.
 >>
 >> If a policy based smart pointer can't accommodate a wide range of
 >> features, I start to wonder if the design itself is inflexible and
 >> flawed. That's why I worry a lot about whether a given PBSP design can
 >> handle apparently marginal uses.
 >
 >That is a strong argument.  On the other hand, should a policy be
 >provided for a configuration that is overly error prone or dangerous?
 >I think the answer may be yes, but only if there is sufficient
 >motivation (like a big performance increase).  Otherwise, no.  Why
 >needlessly expose your clients to a dangerous interface?

There may be two separate issues:

* Should a PBSP supply policies that are prone to be used unsafely?

I'd say "no" is an acceptable answer, at least for something like the T* 
conversion in widely used libraries like the Standard Library and Boost.

* Should a PBSP allow user supplied policies to modify interface, perhaps 
in ways that may be unsafe or even just unfortunate?

That's tougher. At some point I lose interest in a PBSP if it prevents me 
from doing the things I want to do, even if I only want to do them in the 
privacy of my own code.

--Beman