This page is a snapshot from the LWG issues list, see the Library Active Issues List for more information and the meaning of NAD Editorial status.

718. basic_string is not a sequence

Section: 27.4.3 [basic.string] Status: NAD Editorial Submitter: Bo Persson Opened: 2007-08-18 Last modified: 2016-01-28

Priority: Not Prioritized

View other active issues in [basic.string].

View all other issues in [basic.string].

View all issues with NAD Editorial status.

Discussion:

Paragraph 27.4.3 [basic.string]/3 states:

The class template basic_string conforms to the requirements for a Sequence (23.1.1) and for a Reversible Container (23.1).

First of all, 23.2.4 [sequence.reqmts] is no longer "Sequence" but "Sequence container". Secondly, after the resent changes to containers (emplace, push_back, const_iterator parameters to insert and erase), basic_string is not even close to conform to the current requirements.

[ Bellevue: ]

• emplace, for example, may not make sense for strings. Is also likely suboptimal
• with concepts do we need to maintain string as sequence container?
• One approach might be to say something like: string is a sequence except it doesn't have these functions

• basic_string already has push_back
• const_iterator parameters to insert and erase should be added to basic_string
• this leaves emplace to handle -- we have the following options:
  • option 1: add it to string even though it's optional
  • option 2: make emplace optional to sequences (move from table 89 to 90)
  • option 3: say string not sequence (the proposal),
  • option 4: add an exception to basic string wording.

General consensus is to suggest option 2.

[ 2009-07 Frankfurt: ]

Move to NAD Editorial

Proposed resolution:

Remove this sentence, in recognition of the fact that basic_string is not just a vector-light for literal types, but something quite different, a string abstraction in its own right.