Re: Paul Graham's PyCon Keynote

[Paul Graham <address@hidden>]

Two advantages of such non-binary representations of numbers
are that (a) you get bignums automatically and (b) you can
write + in the language.

--Jakub Travnik wrote:
> From: Michael Vanier <mvanier@cs.caltech.edu>
> Subject: Re: Paul Graham's PyCon Keynote
> Date: Thu, 10 Apr 2003 18:14:16 -0700
> 
> > >        but conceptually, we can say:
> > >          data Integer = 0 | 1 | -1 | 2 | -2 | 3 | -3 | ...
> > > 
> > 
> > Or:
> > 
> > data Integer = Zero | Successor Integer | Predecessor Integer
> > 
> 
> Both of solutions are very inefficient, but there are ways to define
> numbers in other way, which leads to system that humans use. It is
> almost as simple (depending on base), it does have finite number of
> constructors and it is efficient for computing with big nubers too:
> 
> data Integer = PositiveTerminator | NegativeTerminator |
>                Zero Integer | One Integer | Two Integer |
>                Three Integer | Four Integer | Five Integer |
>                Six Integer | Seven Integer | Eight Integer |
>                Nine Integer
> 
> so we can get base 10 numbers. We need to choose direction (from most
> significant to least, or reverse):
> so we can write 1234 as
> 
> One Two Three Four PositiveTerminator
> or
> Four Three Two One PositiveTerminator
> depending on chosen direction.
> 
> Arithmetic can be defined in same way as humans do, compute digit by
> digit.
> 
> 
> Jakub Travnik
> jabber://jtra@jabber.com