P4345R0 — Extending C++ with Unicode Mathematical Operators
EWGSG16SG17
We propose that a user be able to declare `operator⊞` and write `a ⊞ b`. That is the whole feature: a frozen set of Unicode symbols that have never had meaning in C++ becomes available as operator tokens, and an operator drawn from that set is an ordinary overloadable function, found by ordinary lookup, called by ordinary overload resolution.