On Wed, 4 May 2011, Andrzej wrote:

>>> 1. (one I mentioned before) Is it just me who thinks that it is a bad
>>> idea to have same quasiquote forms expand correctly in one context and
>>> fail in another?

I sympathize with some of the discomfort with multi-argument UNQUOTE/SPLICING,
and maybe something better can be done (actually what Al* Petrofsky did is
probably more elegant).  However, I don't think a standardization document is
the appropriate place for innovation - after all, it was innovation in the R4RS
definition of QUASIQUOTE that got us into this mess in the first place.  They
just didn't notice that the defintion they wrote was subtly broken.

The Chez solution to this problem (multi-argument unquote) has been in use for a
number of years by several large implementations.  It has he advantage of being
backwards compatible - existing programs not using multi-argument unquote
will not be broken.  The macro is nontrivial but has been thoroughly debugged
and tested over the course of years and can be copied and pasted into any
implementation, so the cost of adopting it is zero.  And the
specification has already been written for R6RS and can be copied and pasted
from there into the WG1 standard, again ast zero cost,  if the editors so
decide.  It is my opinion that this is the best choice that can be made at this
point.

_______________________________________________
Scheme-reports mailing list
Scheme-reports@scheme-reports.org
http://lists.scheme-reports.org/cgi-bin/mailman/listinfo/scheme-reports