To-Be-Proposed Boost Sequences Library

Abstract

This library under development is a re-think of the ideas we've used to represent sequences in C++: containers, iterators, and Ranges.

About dispatching intrinsic operations like begin and end.

About the Cursor and Property Map Abstractions that underlie the Sequence concept.

The Sequence Concept

Sequence is an abstraction that bundles two Cursors and a Property Map.[1] In the table below, S is a model of Sequence and x is a (possibly cv-qualified) instance of S. All names are in namespace boost unless otherwise specified.

Sequence Requirements
Valid Expression	Type	Semantics
sequence::elements(s)	result_of< sequence::id::elements(S&) >::type	Returns a Property Map that accesses the elements of `x`. If `x` is writable, the result is a model of Writable Property Map.
`sequence::begin(x)`	result_of< sequence::id::begin(S&) >::type	Returns a Cursor that, when used with the `elements` property map, traverses the elements of `x`.
`sequence::end(x)`	result_of< sequence::id::end(S&) >::type	Returns a suitble Cursor for terminating the traversal of `x`.

[1]	We realize the standard has already used the term “sequence,” but there are few reasonable terms left and the standard's concept is weak and seldom used.