On Wed, Apr 20, 2011 at 9:14 PM, Denis Shevchenko <for.dshevchenko@gmail.com> wrote:
20.04.2011 18:54, Olaf van der Spek пишет:
Hi,
I've written a small wrapper for std::map::find() (and map-like containers/ranges) that returns a pointer to the value if found (or NULL if not found).
See https://svn.boost.org/trac/boost/ticket/5227
The advantage is that you don't need the container type name (for ::reference), you can initialize the pointer inside an if condition, you don't have to compare against ::end() and you don't have to use ->second.
Hmm... Why not use map::at()?
Compare:
if (very_long_type_name_t::mapped_type* i = find_ptr(very_long_name, 1)) cout << *i << "\n";
with:
try { cout << very_long_name.at( 1 ) << endl; } catch ( const std::exception& /* exc */ ) { cout << "No value with key 1" << endl; }
You don't like exceptions?
IMO exceptions are for exceptional cases. Not finding an element is not an exceptional case. Your variant is also a lot longer / more complex, especially if you want to store the returned reference. Olaf