Re: Using the GNU GMP Library for Bignums in Emacs

[Eli Zaretskii]

> Cc: address@hidden
> From: "Siraphob (Ben) Phipathananunth" <address@hidden>
> Date: Sat, 21 Apr 2018 22:40:05 +0700
> 
> I thought that Eli was talking about how we should interface bignums
> to Emacs Lisp; the + - * / operators are defined in C source
> code.

I never thought we could consider not using + - * etc. with bignums,
so I didn't even raise that issue.

> Bignums would decrease performance in areas where the usual
> 32/64 bit integers are sufficient, and lead to higher memory usage. It
> would make much more sense to have separate math functions for 32/64
> bit numbers and for bignums. In doing so, it should be obvious to the
> Emacs Lisp programmer when to use what.

When the arguments are bignums, these operators should automatically
invoke the relevant GMP functions.  That is how we behave elsewhere in
Emacs; Emacs Lisp does support polymorphism on the level of primitive
functions.  E.g., that's how these operators support both Lisp
integers and Lisp floats (and markers, for that matter).