Hi, On Wed 07 Dec 2011 15:19, l...@gnu.org (Ludovic Courtès) writes:
>>> On Thu 30 Jun 2011 12:44, Andy Wingo <wi...@pobox.com> writes: >>> >>>> I think we should add `when' and `unless' to the default environment. > > Like Marijn, it seems more natural for me to return the values of the > body’s last expression, rather than *unspecified*. Given that there are reasonable cases for `when' and `unless' in side-effecting loops, it is indeed probably best to preserve the <tail sequence> nature of the body of these forms. Are you OK with adding them like this: (define-syntax (when condition stmt stmt* ...) (if condition (begin stmt stmt* ...))) (define-syntax (unless condition stmt stmt* ...) (if (not condition) (begin stmt stmt* ...))) Andy -- http://wingolog.org/
