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Document number: N4128

Date: 2014-10-10

Ranges for the Standard Library, Revision 1

by Eric Niebler

Excerpt:

This paper outlines what support for ranges in the C++ standard library might look like. Rather than presenting a final design, this paper proposes a set of concepts and guidelines for using them to implement range-based versions of the standard algorithms. It draws inspiration from the Boost.Range[4] library, the range algorithms in Adobe Source Libraries[1], Elements of Programming by Stepanov and McJones (2009) [20], and from N3351 “A Concept Design for the STL” by Stroustrup and Sutton (2012) [21]. In addition to presenting the concepts and guidelines, this paper discusses the rationale behind each, weighing different design options.

The decision to defer any discussion about specific wording was taken in recognition of the fact that any range design is likely to undergo significant revision by the committee. The paper is intended merely as a starting point for discussion and as a basis for future work.

This paper assumes the availability of Concepts Lite; however, everything suggested here has been implemented in C++11, where Concepts Lite has been simulated with the help of generalized SFINAE for expressions.