Re: [boost] [move][container] Review Request (new versions of Boost.Move and Boost.Container in sandbox and vault)

Subject: Re: [boost] [move][container] Review Request (new versions of Boost.Move and Boost.Container in sandbox and vault)
From: Jeffrey Hellrung (jhellrung_at_[hidden])
Date: 2009-08-23 04:04:55

Ion Gaztañaga wrote:
> ...new versions of libraries Boost.Move and Boost.Container.

Few comments on proposed Boost.Move:

- Make all metafunctions true MPL metafunctions (as mentioned in 
previous postings).

- BOOST_COPYABLE_AND_MOVABLE definition scopes relative to the global 
scope, while other macros seems to scope relative to the local scope 
(e.g., the difference between ::boost::rv<TYPE> and boost::rv<TYPE>). 
I'm a stickler for consistency, and would probably consider 
::boost::rv<TYPE> et al to be safer.

- What is the rationale for placing BOOST_COPYABLE_AND_MOVABLE and 
BOOST_MOVABLE_BUT_NOT_COPYABLE in the private section of a class 
definition?  IIRC, BOOST_ENABLE_MOVE_EMULATION was suppose to go in the 
public section, and I'm generally wondering what the motivations are for 
specifying public or private.

- Even though this can be gleaned from the code, I'd like to see a "How 
it works" section, e.g., how exactly does the library coerce rvalues 
into binding to the BOOST_RV_REF overload of operator= rather than the 
BOOST_COPY_ASSIGN_REF overload?  Perhaps more generally, I think some 
rationale for why this particular emulation strategy was chosen over 
others would be nice (e.g., the previous proposed Boost.Move used a 
by-value operator= to assign from rvalues efficiently; why the change? 
How does this compare to Adobe's move emulation?).  In most other 
respects, I think the documentation is very good and complete.

- I would've renamed BOOST_COPY_REF_N_TEMPL_ARGS to 
BOOST_COPY_ASSIGN_REF_N_TEMPL_ARGS just to be consistent with 
BOOST_RV_REF and BOOST_RV_REF_N_TEMPL_ARGS.

- Can you comment at all on the stability of the names of the "class 
declaration" macros (e.g., BOOST_MOVABLE_BUT_NOT_COPYABLE)?  I recall a 
previous post that suggested alternative names.  I have no opinion 
either way, I was just curious on the status of that suggestion.

- In the clone_ptr example, would it be more correct to check for 
self-assignment in the move assignment operator (as is done in the copy 
assignment operator) rather than not?

- Overall, great job.  If there's anything I can do to help the 
transition, let me know.

- Jeff