Hello, You say #+nil is not reliable, which I agree with. However, what I'm in the habit of using is #+#:ignore, which AFAIK should be always reliable: #:ignore won't and can't be interned.
Even if #:ignore is in your features, it won't help. CL-USER> (push '#:ignore *features*) (#:IGNORE ...) CL-USER> (+ 1 #+#:ignore 2 3) 4 I do use this in practice, and I also use it as a form of documentation on why I'm commenting something out. As a sort of contrived example: (defun f () #+#:ignore-buggy (progn ...) ; buggy code (progn ...)) ; working code Though, this is certainly clunkier than a dedicated #; macro. Cheers! Robert Smith q...@symbo1ics.com On Sun, May 6, 2012 at 1:57 PM, Pascal Costanza <p...@p-cos.net> wrote: > Hi, > > I'm thinking about writing up a CDR on #;-style comments. Currently, if you > want to comment out a form from CL code, there is no standard way of doing > this. Many people use something like #+nil, or similar tricks, but this is > not 100% reliable. R6RS Scheme introduced #; as a solution, and this seems to > become somewhat popular in CL as well. > > Here is a suggested wording. > > ------------- snip ----------------- > > #; is used to comment out single expressions; the syntax is /#; expression/. > This textual notation is treated as whitespace; that is, it is as if the ``#; > expression'' did not appear and only a space appeared in its place. > > #; operates by skipping over the form. Skipping over the form is accomplished > by binding *read-suppress* to true and then calling read. > > ------------- snip ----------------- > > The text is based on 2.4.8.17 of the HyperSpec. Yes, this would be a fairly > short CDR document. > > Any comments or ideas about this? > > > Best, > Pascal > > -- > Pascal Costanza > > > > > _______________________________________________ > pro mailing list > pro@common-lisp.net > http://lists.common-lisp.net/cgi-bin/mailman/listinfo/pro _______________________________________________ pro mailing list pro@common-lisp.net http://lists.common-lisp.net/cgi-bin/mailman/listinfo/pro
