C++ for Scientists - Technische Universität Dresden

7.6. BEST OF BOTH WORLDS 221
7.6 Best of Both Worlds
The object-oriented programming paradigm offers mechanisms to write libraries that are open
for extension, but it tends to impose intrusive interface requirements on the types that will be
supplied to the library. The generic programming paradigm has seen much success in C++,
partly due to the fact that libraries remain open to extension without imposing the need to
intrusively inherit from particular abstract base classes. However, the static polymorphism that
is a staple of programming with templates and overloads in C++, limits generic programming
applicability in application domains where more dynamic polymorphism is required.
In combining elements of object-oriented programming with those of generic programming, we
take generic programming as the starting point, retaining its central ideas. In particular, generic
programming is built upon the notion of value types that are assignable, copy constructible,
The behavior expected from value types reflects that of C++ built-in types, like int, double,
and so forth. This generally assumes that types encapsulate their memory and resource management
into their constructors, copy-constructors, assignment operators, and destructors, so
that objects can be copied, and passed as parameters by copy, etc., without worrying about
references to their resources becoming aliased or becoming dangling. Value types simplify local
reasoning about programs. Explicitly managing objects on the heap and using pass-by-reference
as the parameter passing mode makes for complex object ownership management (and object
lifetime management in languages that are not garbage collected). Instead, explicitly visible
mechanisms thin wrapper types like reference wrapper in the (draft) C++ standard library ae
used when sharing is desired.
.. more to come..
7.6.1 Compile Time Container
7.6.2 Meta-Functions
7.6.3 Run-Time concepts