[M3devel] INTEGER

[hendrik at topoi.pooq.com]

On Thu, Apr 29, 2010 at 11:07:00AM -0500, Rodney M. Bates wrote:
> Oh, I get it!  You are proposing a _mixed_ approach, where the values
> the programmer can designate are of fixed (though possibly nonstatic)
> size (like open arrays) but the intermediate results are of unbounded
> size that re-adapts to hold the actual value each time an operator is
> evaluated, (like BigInteger).  And because only intermediate results
> work this way, they can be stack allocated, because intermediate
> results have LIFO lifetimes.

In fact, the sizes of intermediate results can be determined statically, 
in theory, at least.  An arithmetic operation with subranges as 
arguments has at most a finite number of possible argument pairs, and 
therefore at mist a finite number of possible results.  A finite set of 
integers has a maximum and a minimum.

In practices, there might be operations (such as shifts and 
exponentiation) for which there bounds are impractical.

-- hendrik

>
> These are quite different approaches to arithmetic.  It does seem
> at least a bit strange to mix them in this way.

Keeping track of the maximum sizes statically makes it a little less 
strange.

-- hendrik