While I'm not sure it's a great idea to #define _, I think we should generally err on the side of providing macros for features than not - since we've missed a few over the years in ways that have mattered.
Looks like the latest revision of the paper has one already. Thanks! Barry On Thu, Jun 15, 2023 at 12:33 AM Corentin via Core <[email protected]> wrote: > + SG10 > This pattern is principally used for global variables, for which > placeholders are not allowed, so I doubt this would be useful. > That being said, I defer to SG10 call, I'm happy to add one if > people think it would have use cases. > > Thanks! > > > > > > > > On Wed, Jun 14, 2023 at 10:33 PM Christof Meerwald <[email protected]> > wrote: > >> Not sure how widespread these workarounds are, but there are >> stackoverflow questions related to this: >> >> >> https://stackoverflow.com/questions/10379691/creating-macro-using-line-for-different-variable-names >> >> https://stackoverflow.com/questions/1082192/how-to-generate-random-variable-names-in-c-using-macros >> https://stackoverflow.com/questions/461062/c-anonymous-variables >> >> (and I think I have seen real-world code using these workarounds) >> >> So I think the use case for a feature-test macro would be something >> like this: >> >> #ifndef __unnamed_placeholder >> #define CONCAT2(a, b) a ## b >> #define CONCAT(a, b) CONCAT2(a, b) >> #ifdef __COUNTER__ >> #define _ CONCAT(placeholder, __COUNTER__) >> #else >> #define _ CONCAT(placeholder, __LINE__) >> #endif >> #endif >> >> void f() >> { >> int _ = 1; >> int _ = 2; >> } >> >> >> Christof >> >> -- >> >> https://cmeerw.org sip:cmeerw at cmeerw.org >> mailto:cmeerw at cmeerw.org xmpp:cmeerw at cmeerw.org >> > _______________________________________________ > Core mailing list > [email protected] > Subscription: https://lists.isocpp.org/mailman/listinfo.cgi/core > Link to this post: http://lists.isocpp.org/core/2023/06/14395.php >
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