[Python-Dev] PEP 0484 - the Numeric Tower

[Random832]

> From Lib/numbers.py:
>
> ## Notes on Decimal
> ## ----------------
> ## Decimal has all of the methods specified by the Real abc, but it should
> ## not be registered as a Real because decimals do not interoperate with
> ## binary floats (i.e.  Decimal('3.14') + 2.71828 is undefined).  But,
> ## abstract reals are expected to interoperate (i.e. R1 + R2 should be
> ## expected to work if R1 and R2 are both Reals).

Why?