It seems you are proposing to change the language for floats to require an
explicit decimal point. This is one option, but not my favorite. I don't
care for the backslash-- it is too easy to forget, and it doesn't always
lead to an error message.
Also it is not backward compatible.
I think that input of hexadecimal could be done by just adding a function.
For example, read_from_string("ff00",16).
This is not an important issue if the program works OK as long as ibase is
set to some normal value.
RJF