Concepts Definitions

This is the thorough definition the concepts used by G_sTL algorithms.

The different fields of the description are the following:

Refinement of:

concept B is said to be a refinement of concept A if the requirements of A are a subset of the requirements of B. Consider the example of a Forward Iterator. A forward iterator is an object that points to other objects. It is used to iterate over a range of objects, in a single direction: it does not allow to go backward. The concept of Forward Iterator hence requires an operator ++ to advance to the next object of the range, an operator * which allows access to the value the iterator is pointing to, an operator != to compare two iterators, and an operator = which assigns an iterator to another. A Bidirectional Iterator is an iterator which allows to iterate over a range of objects in both forward and backward directions. It thus requires the same four operators as Forward Iterator, plus operator -, which moves the iterator to the previous object in the range. Since the requirements of Forward Iterator are a subset of the requirements of Bidirectional Iterator, Bidirectional Iterator is a refinement of a Forward Iterator. Following this definition, if concept B is a refinement of concept A, any model of B is also a model of A.

Associated types:

a list of C++ types associated to the concept

Notations:

some notations used in the remaining of the description of the concept

Valid expressions:

a list of expressions that can be applied to a model of the concept. For instance, if iter is a model of the afore-mentioned Forward Iterator concept, such valid expression could be iter++ or *iter.

Models:

some examples of models of the concept.