Re: Please help with testing & improving a StringValue class

From:

"Alf P. Steinbach" <alfps@start.no>

Newsgroups:

comp.lang.c++

Date:

Sun, 09 Sep 2007 21:56:42 +0200

Message-ID:

<13e8js2fbmi3ja2@corp.supernews.com>

* Alf P. Steinbach:

...

Reusing most of the text I posted for the 01 version:

An 02 version of StringValue is now available at
<url: http://home.no.net/alfps/cpp/lib/alfs_v02.zip>.

Yep, seems like I've partially rediscovered the joy of coding...

Old features:

   * A StringValue can be constructed from a literal in constant
     time with no dynamic allocation.

   * A StringValue can be constructed from a pointer and deletion
     operation (functor or function) in constant time, with no O(n)
     copying.

   * A StringValue can be copied and assigned in constant time with
     no dynamic allocation (great for e.g. standard containers).

   * A StringValue can be safely constructed in other ways, including
     from a 'char const*' and from a 'std::string', but then involving
     O(n) copying and dynamic allocation.

   * A StringValue can be freely copied and assigned, but the value
     can not be modified.

   * A license reference (Boost license) is included in every file,
     resulting from comments by Roland Pibinger (thanks).

   * operator==, operator< added,
     resulting from comments by Barry <dhb52@2000.com> (thanks).

   * Implicit conversion to 'char const*' /removed/, because

   * A class StringValueOrNull was added, which supports passing
     null-values around. A StringValue is implicitly convertible to
     StringValueOrNull. A StringValueOrNull value can only be explicitly
     converted to pure StringValue, then with checking of nullvalue &
     possible exception.

   * Support for << and >> stream i/o added (because of removal of
     implicit conversion to 'char const*').

New features:

   * In order to be useful in Windows programming, wchar_t versions of
     StringValue (WStringValue) and StringValueOrNull (ditto) have
     been added, i.e. templatization on the character type.

   * Free function swap implementations moved from namespace std to
     namespace alfs, resulting from comments by Greg Herlihy (thanks).

   * Two small example usage programs, one an abstraction of the 'main'
     arguments (with almost no overhead), and one ditto showing a simple
     abstraction of Windows Unicode command line arguments.

Comments, ideas, criticism etc. welcome! Note: almost not tested code.
  At least not formally tested!

<< and >> i/o for wide streams not implemented, because wide streams are
not implemented by MingW g++ 3.4.4.

(I'm wondering whether SharedArray should provide indexing, and/or
perhaps keep track of the length of the array: perplexingly and almost
paradoxically, it hasn't been needed. I'm also wondering whether there
is some better way to steer constructor selection (in StringValue and
StringValueOrNull) the Right Way, currently using boost::disable_if?)

Cheers, & hope this can be interesting,

- Alf