Re: integer overflow

["Stephen J. Turnbull" <turnbull@sk.tsukuba.ac.jp>]

David Kastrup writes:
 > Richard Stallman <rms@gnu.org> writes:
 > 
 > > I have heard that Guile now supports Emacs Lisp.  And it has bignums.
 > > So if we make Emacs use Guile, that will automatically provide
 > > bignums.
 > 
 > My first reaction to that would be "Whoa, whoa, whoa!".
 > 
 > The second that "librep" might be an easier starting point for migrating
 > the Lisp engine.

For bignums, XEmacs or SXEmacs might be easier yet.  The work of
integrating bignums (GNU MP and BSD MP are both supported as
compile-time options) was done by Jerry James.  He is probably *not*
available any time soon (his day job just turned into a day-and-night
job) but the pedigree of the code is easily established and he and
other contributors probably would be willing to sign papers.

I believe SXEmacs supports quaternions and Gaussian integers, and
perhaps even more exotic number systems. :-)  However, I have no idea
whether the SXEmacs folks would be willing to assign their
contributions.

However, this is all kind of irrelevant.  Using bignums as pure
numbers is relatively easy.  The hard part is introducing them as
numerical components of internal Emacs structures (buffer size and
positions, markers, overlays, text properties), and integrating them
with niceties like (system-dependent) large file support, etc.  This
is in no way an automatic consequence of language support for bignums.