[Python-ideas] numerical type combining integer and float/decimal properties [Was: Re: Python Numbers as Human Concept Decimal System]

[Wolfgang Maier]

Chris Angelico <rosuav at ...> writes:

> 
> On Tue, Mar 11, 2014 at 7:57 AM, Ethan Furman <ethan at ...> wrote:
> > I think he's saying make a new type similarly to complex, only instead of
> > two floats to make a complex number, have a (long) int and a decimal float
> > to make this new type.  The long int portion would have infinite precision,
> > the float portion would have, say, 16 digits (or whatever).
> 
> That's plausible as a representation, and looks tempting, but basic
> arithmetic operations become more complicated. Addition and
> subtraction just need to worry about carries, but multiplication forks
> out into four multiplications (int*int, int*frac, frac*int,
> frac*frac), and division becomes similarly complicated. Would it
> really be beneficial?
> 

That's right, it would complicate calculations exactly as you are pointing
out. That's why I said it might be too slow for most users even when
implemented optimally, but then I'm not sure whether performance should be
the very first thing to discuss.

Best,
Wolfgang