In case it is helpful, here are the notes I used for discussion of CWG#1871 in today's EWG telecon.

CWG#1871 in EWG:
- No objection to unanimous consent to reject; 7 attendees.
- Reasons for rejection include:
  - Issue is not well motivated.
  - SG16 is currently working on a proposal, P1949, to refine allowed identifiers.  It isn't clear how non-identifier UDLs would fit into that.
  - A new preprocessing token kind would be required (not for the literal itself, but for the UDL declaration).
  - Allowing '$' would be problematic:
    - it isn't in the basic source character set.
    - Some compilers allow it in identifiers.
  - Currency symbols are overloaded; '$' doesn't mean USD, so these symbols are already not uniquely useful.
  - ISO 4217 specifies currency identifiers and they are already used in finance.
  - Adopting symbols for this purpose would prevent their use for other, likely more valuable purposes; as operators for example.
  - Anyone wishing to pursue this further should write a paper that provides a principled specification for which symbols to permit.


On 5/6/20 5:30 PM, JF Bastien wrote:
I can do it first thing in the call.

On Wed, May 6, 2020 at 1:52 PM Tom Honermann <> wrote:
On 5/6/20 2:40 PM, JF Bastien wrote:
On Mon, May 4, 2020 at 10:28 PM Tom Honermann <> wrote:
On 5/5/20 1:25 AM, JF Bastien wrote:
Thanks! Can someone from SG16 represent this position at Thursday’s EWG telecon (10–11:30 Pacific)?

Yes.  I'm under time pressure this week, so I'll try to find a volunteer to do so, but if I'm unable to find one, I'll join the call.

To confirm: did you find a volunteer for tomorrow's call, 10AM Pacific?

No takers, so I'll join the call.  If you can schedule this early during the telecon, I would appreciate it (I'm trying to wrap up a new release at work this week, so short on time).




On Mon, May 4, 2020 at 10:00 PM Tom Honermann <> wrote:
On 4/7/20 11:37 PM, Tom Honermann wrote:
On 4/7/20 11:23 PM, JF Bastien via SG16 wrote:
Hi SG16,

I'd like you to take on CWG issue #1871:

1871. Non-identifier characters in ud-suffix

Section: 5.13.8  [lex.ext]     Status: extension     Submitter: Richard Smith     Date: 2014-02-17

(From messages 24712 through 247142471624717, and 24719.)

ud-suffix is defined in 5.13.8 [lex.ext] as an identifier. This prevents plausible user-defined literals for currency symbols, which are not categorized as identifier characters.

Rationale (June, 2014):

CWG felt that a decision on whether to allow this capability or not should be considered by EWG.

Please let EWG know what you think, given the ongoing TR31 work. EWG will then discuss your proposal, hopefully adopting it as-is, and forward to CWG.

Sounds good.  I filed an SG16 issue ( to ensure we follow up on this.  We'll discuss at an upcoming telecon.

SG16 discussed this at our April 22nd, 2020 telecon.

The following poll was performed:

Poll: Is there any objection to unanimous consent for recommending rejection of this proposal?
- No objection to unanimous consent.

So, SG16 consensus is (so far) unanimous to reject this issue.  Per our operating procedures, objections to the consensus can be raised over the next week (I just posted notification of the poll today), but I'm not anticipating any.  I advise EWG to proceed with this recommendation at its leisure.