DIP58: ".." as a Binary Operator

[Mason McGill]

> It's a nice proposal, but what happens if you want a range of 
> floats, e.g., 1.0..2.0?

Correct me if I'm wrong, parsing would look like:

----------------------------------------
1.0..2.0
===      Found a literal.

1.0..2.0
    ==    Found a binary operator.

1.0..2.0
      === Found a literal.
----------------------------------------

Something like `5....5` could also compile (since there's only 1 
valid parsing), though such a thing is clearly an abomination, so 
I'd write it `5. .. .5` or `(5.)..(.5)`.  The whole ordeal is 
probably a bit of insight into why other languages use the ':' 
character for slicing.