P2465 Standard Library Modules std and std.compat

[brycelelbach]

P2465R0 Standard Library Modules std and std.all (Stephan T. Lavavej, Gabriel Dos Reis, Bjarne Stroustrup, Jonathan Wakely)

[brycelelbach]

2021-10-12 Library Evolution Telecon

P2465R0: Standard Library Modules std and std.all

2021-10-12 Library Evolution Telecon Minutes

Chair: Bryce Adelstein Lelbach

Champion: Stephan T Lavavej

Minute Taker: Steve Downey

Start: 2021-10-12 10:09 Pacific

Does this proposal have:

• Examples?
  • Yes.
• Implementation experience?
  • Some.
• Usage experience?
  • No.
• Deployment experience?
  • No.
• Performance considerations?
  • Yes.
• Discussion of prior art?
  • Yes.
• Changes Library Evolution previously requested?
  • Yes.
• Wording?
  • Yes.
• Feature test macro?

Topics to Polls:

• Design options:
  • std:: only module and global only module.
  • std:: only module and std:: + global module.
• Names.

POLL: Provide both
0) a std:: only module, and

1. a std:: + global module
   (what's currently in the paper and preferred by the authors).

Strongly Favor	Weakly Favor	Neutral	Weakly Against	Strongly Against
8	8	5	1	0

Attendance: 30

# of Authors: 3

Author Position: 3 x SF

Outcome: Consensus in favor.

POLL: Provide both
0) a std:: only module, and

1. a global only module.

Strongly Favor	Weakly Favor	Neutral	Weakly Against	Strongly Against
6	5	5	3	2

Attendance: 30

# of Authors: 3

Author Position: 2 x SA, 1 x N

Outcome: No consensus.

POLL: Provide the following standard library modules (vote once):

Option	Votes
(A) std:: only and std:: + global	13
(B) std:: only and global only	8

Attendance: 31

# of Authors: 3

Author Position: 3 x A

Outcome: Option (A) has the stronger consensus.

POLL: The std:: only module should be named std.

Strongly Favor	Weakly Favor	Neutral	Weakly Against	Strongly Against
7	15	1	0	2

Attendance: 31

# of Authors: 3

Author Position: 3 x SF

Outcome: Consensus in favor.

POLL: The std:: + global module should be of the form std.X (where X is a placeholder).

Strongly Favor	Weakly Favor	Neutral	Weakly Against	Strongly Against
6	8	6	3	0

Attendance: 28

# of Authors: 3

Author Position: 3 x SF

Outcome: Weak consensus in favor.

POLL: The std:: + global module should be of the form std_X (where X is a placeholder).

Strongly Favor	Weakly Favor	Neutral	Weakly Against	Strongly Against
0	0	10	9	2

Attendance: 28

# of Authors: 3

Author Position: 1 x WA, 2 x SA

Outcome: Consensus against.

POLL: The std:: + global module should be of the form stdX (where X is a placeholder).

Strongly Favor	Weakly Favor	Neutral	Weakly Against	Strongly Against
4	6	7	5	2

Attendance: 28

# of Authors: 3

Author Position: 1 x WA, 2 x SA

Outcome: No consensus.

SA: I find it harder to read without punctuation in the middle. That's why I
was SA this one, but WA the underscore poll.

POLL: The std:: + global module should be named std.all.

Strongly Favor	Weakly Favor	Neutral	Weakly Against	Strongly Against
3	9	4	5	4

Attendance: 28

# of Authors: 3

Author Position: 3 x SF

Outcome: No consensus.

POLL: The std:: + global module should be named std.compat.

Strongly Favor	Weakly Favor	Neutral	Weakly Against	Strongly Against
7	10	5	3	0

Attendance: 28

# of Authors: 3

Author Position: 1 x N, 2 x WF

Outcome: Consensus in favor.

POLL: Modify P2465R0 (Standard Library Modules std and std.all) by renaming std.all to std.compat, and then send the revised paper to LWG for C++23 with priority B1 (to be confirmed with a Library Evolution electronic poll).

Strongly Favor	Weakly Favor	Neutral	Weakly Against	Strongly Against
14	8	0	2	1

Attendance: 27

# of Authors: 3

Author Position: 3 x SF

Outcome: Consensus in favor.

WA: I don't think std.compat is a good name.

WA & SA: I am against the land grab of std.

End: 11:28

Summary

We reviewed P2465R0 (Standard Library Modules std and std.all), which proposes a minimal form of Standard Library modules.

During our last discussion of this topic, we determined that we wanted a module that only exported the names in std:: (as well as operator new/delete).

Today, we discussed whether we should have a second module which either

• exports all the names in std:: plus global names (e.g. ::fopen), or
• exports only global names (e.g. ::fopen).

We had a preference for first option, a std:: + global module. There was some suggestion that we could have both options, in addition to a std:: only module, but there was no noted support for this.

We also concluded our discussion about how these modules should be named. First, we decided that the std:: only module should be called std.

The naming of the std:: + global module was a bit more complicated. The original proposal was std.all, but some were concerned about having a module with a subordinate name (e.g. std.X) that was a superset of its parent (e.g. std), even though the module name syntax does not express any semantic hierarchy. Underscores as a delimiter were also considered, but some were worried about inconsistencies between std.X modules and std_X modules in the future. An undelimited form, stdX, was also suggested.

Ultimately, we only had consensus for the std.X pattern. We settled on the name std.compat for the std:: plus global module.

Outcome

Library Evolution sends P2465R0 (Standard Library Modules std and std.all), renaming std.all to std.compat, to LWG, for C++23, classified as a focus (P0592 bucket 1 item). This will be confirmed via a Library Evolution electronic poll.

[wg21bot]

P2465R1 Standard Library Modules std and std.compat (Stephan T. Lavavej, Gabriel Dos Reis, Bjarne Stroustrup, Jonathan Wakely)