On Wed, 16 Sep 2009, Aaron W. Hsu wrote: > On Tue, 15 Sep 2009 22:36:35 -0400, Ray Dillinger <[email protected]> wrote: > >> Seriously, it seems to be a construct that causes considerable >> hair in Common Lisp, and nobody knows how to make it less hairy. > > EVAL-WHEN is very hairy, and that is precisely why everyone avoids using > it whenever possible.
The phase semantics of R6RS libraries was designed (see the initial paper by Matthew Flatt) to address this problem and mostly eliminate the need for eval-when. There are those who rightly complain that library phases are complicated. That is true, but they are considerably less hairy than eval-when. Ikarus simplifies this problem by doing automatic phase inference, but this may cause other problems for inexpert users. IMHO, while we have made a start in R6RS, the problem of phases remains to be satisfactorily addressed. Andre _______________________________________________ r6rs-discuss mailing list [email protected] http://lists.r6rs.org/cgi-bin/mailman/listinfo/r6rs-discuss
