17 Jan 2008 18:33
Re: MAYBECALL
Tobias C. Rittweiler <tcr <at> freebits.de>
2008-01-17 17:33:53 GMT
2008-01-17 17:33:53 GMT
"Attila Lendvai" <attila.lendvai <at> gmail.com> writes: >> (maybecall (not (listp thing)) #'list thing) == (ensure-list thing) > > i don't see in which aspect it is better than writing > > (unless (listp thing) > (list thing)) This would return NIL if THING is not a list. MAYBECALL behaves like a identity function in that case, making it practical for chaining. > note that the rationale for ensure-list is that it's actually a bit > shorter and also encodes the intention in a way that is much easier > for a human to process (which, imho, can not be said for maybecall). I haven't said anything about taking ENSURE-LIST &c out. MAYBECALL behaves to ENSURE-FOO as LAMBDA behaves to DEFUN/FLET. An advantage of FUNCALL-IF is also single evaluation of its arguments, so I actually opt for its inclusion. -T.c
RSS Feed