On Wed, Mar 4, 2020 at 6:28 PM J Decker via Std-Proposals <std-proposals@lists.isocpp.org> wrote:

Allow '_' to be found in a number token, and ignored for generating the resulting token. Allow specifying numbers with underscores like 0x1234_5678; 123_534.000_003 ; can include trailing underscores, and just terminate on the next whitespace or operator...

This is the proposal that was applied for ECMA Script
https://github.com/tc39/proposal-numeric-separator

This is my Proposal
https://gist.github.com/d3x0r/93f8da65f79de66a9736754fdfd99f54

J

In case anyone is curious, the original digit separators proposal did use underscores: http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2281.html

A subsequent draft included a whole bunch of different options: http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2013/n3499.html

Before going back to underscore: http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2013/n3661.html

and finally the single quote we've had since C++14: http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2013/n3781.pdf

Barry