The other question is, whether by themselves incomplete strings would/should work   1. F"a={a"   F"}" or 2. "a+b={a"   F"+b}" or even 3. F"abs(a)={a"   "bs(a)}" and 4. the last example yes or no, even if abs is implemented as a macro?   Jens pointed out that tokenization and macro expansion happen before string concatenation, so at the very least 4. would definitely not fit to the current phases. Probably 3. neither with the initially separated abs symbol.   Would a F string count as a single token string literal or as several tokens or kind of both?   -----Ursprüngliche Nachricht----- Von:Tom Honermann via Std-Proposals <std-proposals_at_[hidden]> Gesendet:Mi 18.10.2023 21:55 Betreff:Re: [std-proposals] Supporting f-strings in C++: draft-R1 An:std-proposals_at_[hidden]; CC:Tom Honermann <tom_at_[hidden]>; On 10/17/23 2:19 AM, Hadriel Kaplan via Std-Proposals wrote: From: Std-Proposals <std-proposals-bounces_at_[hidden]> <mailto:std-proposals-bounces_at_[hidden]> on behalf of Sebastian Wittmeier via Std-Proposals <std-proposals_at_[hidden]> <mailto:std-proposals_at_[hidden]> But overall, I was arguing for rather better (and less surprising) support of the preprocessor, as otherwise it could lead to hard to find bugs. Yeah I think I'm leaning that way too. I think that most users will expect it to behave like simple textual transformation. And I think most would expect that macros work - especially if some C-functions are actually implemented as macros, such as abs() and similar. Plus I bet using __FILE__, __LINE__, __PRETTY_FUNCTION__, etc. will be done by plenty of people, and cause frustration when they don't work. (and there is no formatter specialization for std::source_location today either, fwiw) --- If we do this in the preprocessor, then I think the easiest/cleanest way would be to make it similar to the unary _Pragma() operator. But do we expect any of these to compile, and if so which ones?: 1) X"a={a}" X"b={b}" 2) X"a={a}" "b={b}" 3) "a={a}" X"b={b}" 4) F"a={a}" F"b={b}" 5) F"a={a}" "b={b}" 6) "a={a}" F"b={b}" 7) F"a={a}" X"b={b}" 8) X"a={a}" F"b={b}" Deviations from the pattern shown in the table in [lex.string]p8 <http://eel.is/c++draft/lex.string#8> are likely to be considered surprising so should come with strong motivation. That table suggests that 1-6 be well-formed, that each member of the sets of 1-3 and 4-6 have the same meaning, and that 7-8 are ill-formed. Tom. -hadriel Juniper Public -- Std-Proposals mailing list Std-Proposals_at_[hidden] https://lists.isocpp.org/mailman/listinfo.cgi/std-proposals