[r6rs-discuss] [Formal] Quasiquote should support unquotation within bytes objects.

David Van Horn dvanhorn at cs.brandeis.edu
Thu Nov 16 00:43:22 EST 2006


John Cowan wrote:
> Abdulaziz Ghuloum scripsit:
> 
>> The problem with the above is that (unquote a), (unquote b) and 
>> (unquote-splicing cs) are not unsigned-8 values; you just cannot put 
>> them in a vu8.  Supporting your proposal severely complicates the 
>> reader and the expander since you have to perform macro expansion while 
>> reading; this may not even be possible.
> 
> This is where SRFI-10 comes in handy.

As far as I can tell, SRFI-10 does not help in this case.

To simplify Felix Klock's original example:

(let ((a 0) (b 1))
   `#vu8(,a ,b))
==> #vu8(0 1)

This would become, using SRFI-10:

(let ((a 0) (b 1))
   #,(vu8 a b))

But here, the reader associated with vu8 would be applied to the symbol 
'a and 'b, not 0 and 1.

David



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