[boost] [XInt] Some after thoughts

Subject: [boost] [XInt] Some after thoughts
From: falcou (Joel.Falcou_at_[hidden])
Date: 2011-03-10 04:06:43

Ok, as the ET based rambling went nowhere and some people (especially
Steven)
had some valid point on the simplicity of the underlying representation, i
am about
to propose the following plan. The premises still are that I believe that
at some point
an ET layers is worthwhile. So here it is:

1/ restructure XInt so a generic way to access to the needed internals of
the big integer representation
through a terse Concept providing way to specify how to store and retirvee
bits o.

2/ Build the xinteger_t type on top of this generic layer.

Let's stop here. At this point, we fulfill needs expressed by Chad and
Steven: a simple and
generic large integer library ready to be used. Now this I can see as a
very valid candiate to
be accepted right now. So now, what's going afterward ?

By using the concept and interface, we ( and by we, maybe I mean only me
for the moment) can
do the following:

3/ implement a EDSL on top of the interface defined in 1/ By reusing the
low level memory and computation interface
we can build a ET-enabled large integer that behave the same way than the
original large integer type in 2/ but allow us to
add "fancy" optimisations

4/ Have a way to say large integer use SIMD register of 128 bits and
implement a SIMD aware large integer

Or any combination of 3+4 or any other similar extension.

So, can the effort required by 1/ (definition of a minimal concept  for
handling representation of large integer) and 2/
seems valid ? I think this actually gives everything to everyone : the
simplicity concerned public and the "fancy" public.
Of course, the only thing Chad may have to do is 1+2, leaving 3+ to people
interested to provide such extension later.

How does it sound ?