On Wed, 30 Apr 2014 13:52:48 PDT Bear <[email protected]> wrote:
> On Mon, 2014-04-28 at 23:48 -0400, John Cowan wrote:
> 
> > 1) Should R7RS-large require arbitrarily large (up to implementation
> > restrictions like memory) exact integers?
> 
> It should require exact integers.  It should encourage range 
> limits much higher than typical programming languages. It 
> should not require an implementation to exhaust all memory 
> and crash in an attempt to represent a very large exact integer.  

I translate this to mean this: An implementation neeeds to
specify this limit in a symbolic constant in some form. It
should probably be a pair (x y) to  indicate x^y (otherwise
just the "constant" will eat up all memory!).


> > 2) Should R7RS-large require support for exact rational numbers?
> 
> It should require exact ratios.  It should not require an 
> implementation to exhaust all memory and crash in an attempt 
> to represent a very precise ratio.  

Ditto.

> > 3) Should R7RS-large require support for exact complex numbers?
> 
> Previously I voted 'yes' subject to the same representation limits 
> as other exact numbers.  But as I consider this there's an issue. 
> 
> I would vote 'yes' for consistency with the rest of the numeric 
> tower, but it is hard to say exactly what a 'yes' here means in 
> the absence of any constraint on whether the exact numbers 
> represented are, eg, stored in polar or cartesian format, or in 
> some union that could be either, and if in polar format whether 
> the angle measurement is given in radians (either directly or as 
> some product of pi like degrees), or as a slope ratio.

I have difficulty imagining the usefulness of "exact" polar
representation. Seems to me, if you do allow exact complex
numbers, for polar<->cartesian conversion you would need
big-floats.

But must admit I am unclear about what "target audience or
market" R7RS-large is being designed for. I use it to solve
practical problems or for exploratory programming, in place of
perl/python/ruby/language-du-jour :-)

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