Re: Using the GNU GMP Library for Bignums in Emacs

[Daniel Colascione]

On 04/22/2018 10:43 AM, Paul Eggert wrote:
> Philipp Stephani wrote:
> > integers are currently documented to use modular arithmetic (
>
> We'll need to change the documentation for modular arithmetic, since 
> integers will no longer overflow.

Bugs will inevitably arise. One possibility is just dealing with them; 
another might be to predicate bignum support on a lexical-binding-like flag.

> > and they are documented to be pure value types, i.e. same-valued integers
> > are the same objects. Especially the second property is widely used.
>
> This property is used only for fixnums now (since bignums do not exist 
> yet), and we can keep this property for fixnums. We could also keep it 
> for bignums, by hashing all bignums, though I doubt whether it's worth 
> the expense.

That's a good idea, IMHO. It preserves identity without complicating eq 
itself.