[alexandria-devel] Re: MAYBECALL

[Tobias C. Rittweiler]

"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