On Nov 3, 2013, at 10:01 PM, Mikael <mikael.rcv@gmail.com> wrote:

> Dear Marc,
>
> The procedure ordinarily reached as + , can it be reached under some alternative name in code with (declare (fixnum)) ?

Here's how I would do it:

(declare (standard-bindings) (fixnum) (not safe))

(define (double1 x)
  (+  ;; uses fixnum specific + (i.e. ##fx+)
   x
   x))

(define (double2 x)
  ((let () (declare (generic)) +)  ;; uses generic +
   x
   x))

You could also call the procedure ##+, but it is not an exact replacement for + because the error handling is different (try (##+ 1 'foo)) and it must be passed 2 parameters.

Marc