So far I would say we've had some good contributions on this thread.
Ivan's suggested patches show that the change isn't completely trivial,
but is doable.
However, we haven't had any input from an R Core member, so I consider
the proposal to be essentially dead.
If an R Core member decides to resurrect it, here's what I'd suggest is
still needed:
- a formal definition of where the separator may occur, and a
justificaton for that choice, and comparison to other languages.
- patches to documentation for the changes. These include the manuals
and the ?NumericConstants help topic, and probably others.
- tests to add to "R CMD check" for packages to see if the new syntax
is being used without specifying that "R >= 4.3.0" is a requirement.
Duncan Murdoch