[boost] [review] Formal review of the Smart Container library extended

From: Pavol Droba (droba_at_[hidden])
Date: 2004-10-07 04:31:53

Hi Boosters,

Formal review of the Smart Containers library from Thorsten Ottosen
has been extended until Saturday, October 7th 2004).

Any opinions or reviews are more then welcome.

Regards,
Pavol Droba

Original invitation message is here:

The review of the Smart Container library, written by Thorsten Ottosen
starts today (September 26th, 2004) and runs for 10 days (until
October 5th, 2004).

The latest version of the library can be found at

http://boost-sandbox.sourceforge.net/smart_container.zip
or
http://groups.yahoo.com/group/boost/files/pointer%20container/smart_container.zip

The package contains all you need to sucessfuly use the library with
the Boost version 1.31 or later, however library tests require the
latest Boost.Test, that is available from the main Boost CVS.

What does the library provide? The library documentation states:

>>>>>>>>>>>>>>>>

Whenever a programmer wants to have a container of pointers to heap-allocated objects, there is usually only one
exception-safe way: to make a container of smart pointers like boost::shared_ptr. This approach is suboptimal if

   1. the stored objects are not shared, but owned exclusively, or
   2. the overhead implied by smart pointers is inappropriate

This library therefore provides standard-like containers that are for storing heap-allocated or cloned objects
(or in case of a map, the mapped object must be a heap-allocated or cloned object). For each of the standard
containers there is a smart container equivalent that takes ownership of the objects in an exception safe manner.
In this respect the library is intended to solve the so-called polymorphic class problem.

The advantages of smart containers are

   1. Exception-safe and fool proof pointer storage and manipulation.
   2. Notational convenience compared to the use of containers of pointers.
   3. Can be used for types that are neither Assignable nor Copy Constructible.
   4. No memory-overhead as containers of smart pointers can have (see 11 and 12).
   5. Usually faster than using containers of smart pointers (see 11 and 12).
   6. The interface is slightly changed towards the domain of pointers instead of relying on the
      normal value-based interface. For example, now it is possible for pop_back() to return the removed element.

The disadvantages are

   1. Less flexible than containers of smart pointers

<<<<<<<<<<<<<<<

As an example of how the new containers look like, consider that

<code>
    typedef boost::shared_ptr<Foo> foo_ptr;
    std::vector<foo_ptr> vec;
    vec.push_back( foo_ptr( new Foo ) );
    (*vec.begin())->bar();
</code>

now becomes

<code>
    boost::ptr_vector<Foo> vec;
    vec.push_back( new Foo );
    vec.begin()->bar();
</code>

In your reviews, please include the answers for the following
questions:

    * What is your evaluation of the design?
    * What is your evaluation of the implementation?
    * What is your evaluation of the documentation?
    * What is your evaluation of the potential usefulness of the library?
    * Did you try to use the library?  With what compiler?  Did you have any problems?
    * How much effort did you put into your evaluation? A glance? A quick reading? In-depth study?
    * Are you knowledgeable about the problem domain?

And finally, every review should answer this question:

   * Do you think the library should be accepted as a Boost library?
     Be sure to say this explicitly so that your other comments don't obscure your
     overall opinion.

Also, in the documentation you will find questions from the submitter to the
reviewer; whenever you feel you have something to contribute on these issues,
please don't hessitate to include that in your review.

Thank you,
Pavol Droba, review manager for the Smart Containers library.  

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