P1433 Compile Time Regular Expressions

[jensmaurer]

P1433R0 Compile Time Regular Expressions (Hana Dusíková)

[tahonermann]

SG16 discussed this paper in Kona and provided guidance to the author. Removing the SG16 label.

[brycelelbach]

Discussed at the Kona 2019 meeting by LEWGI

Champion: Hana Dusíková

Minute Taker: Ben Craig

Start Overview: 14:22

Start Discussion: 14:35

The Unicode story needs to be addressed; this paper will be seen by SG16 as well.

Start Polling: 14:46

POLL: We should promise more committee time to pursuing P1433R0, knowing that our time is scarce and this will leave less time for other work.

Strongly For	Weakly For	Neutral	Weakly Against	Strongly Against
14	1	2	0	0

Attendance: 17

// 0
regex_match<"pattern">(subject);

// 1
using namespace std::regex_literals;
regex_match(subject, "pattern"re);

// 2
// Needs parametric expressions (P1221) or constexpr function params (P1045).
static_regex_match(subject, "pattern");

// 3
// Can be done with consteval.
regex_match(subject, static_regex("pattern"));

POLL: Vote for the ones you like (you can pick more than one).

Option	Votes
0	8
1	5
2	7
3	8

Attendance: 17

No clear consensus for any option, except that we don't like option 1 as much. The author may choose to pursue either option 0, 2, or 3.

POLL: For this paper, only support one regex dialect (which one is TBD by future discussion).

NO OBJECTION TO UNANIMOUS CONSENT

Attendance: 17

POLL: For std::regex, move towards supporting one regex dialect (which one is TBD by future discussion).

Strongly For	Weakly For	Neutral	Weakly Against	Strongly Against
5	1	7	0	1

Attendance: 17

That has consensus.

David (SA): I don’t think we’ve done sufficient research to answer that question.

Volunteers to Help Revise: David Stone

End: 15:05

CONSENSUS: Bring a revision of P1433R0, with the guidance below, to LEWGI for further design review.

• Pick one of the three syntax options we liked (option 0, 2, or 3 from above) and focus on that for now.
• Just support one regex dialect; explore which one to support in the next revision.
• Return with a story for Unicode support.

[cor3ntin]

@brycelelbach you remember why this has an ewgi tag?