[gambit-list] Is there a way to return "nothing"?

Adrien Pierard pierarda at iro.umontreal.ca
Mon Apr 30 10:50:58 EDT 2007

> Is there a way to return "nothing"?
> so that :
> (list nothing 1 2 3 nothing 4 5 6) ; => (1 2 3 4 5 6)

I was last week wondering about something really close to thise question
Is it possible to write a macro that expands to nothing ?
(ideally, a portable way to do it)

In C, one can write 
#define NOTHING
NOTHING printf NOTHING (NOTHING "%d\n",x);

So, I naively tried
(define-syntax nothing
But it wouldn't compile.

The aim is to embed code as a macro in another file, and with the right
parser, to be able to fetch back this data (no, it's not steganography,
just Scheme code annotation in Scheme)
Roughly speaking, I want to write comments in scheme (that would be
parsed by the REPL, and stripped by the macro)


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