Adds @, $ and backtick to the basic character set.
Other papers in Lexer & Unicode cleanup (C++26/29)
P1854R4Making non-encodable string literals ill-formedVarna 2023P2361R6Unevaluated stringsVarna 2023P2621R2UB? In my Lexer?Varna 2023P3658R1Adjust _identifier_ following new Unicode recommendationsBrno 2026P3733R1More named universal character escapesBrno 2026All 6 papers in Lexer & Unicode cleanup (C++26/29) →