Need for #+ and #-

[Jon White <JLW@SU-AI.ARPA>]

Apologies if I'm addressing a non-problem here, but a quick scan of the CL
main for the past two weeks there seemed to show an undercurrent of question
about the need for #+ and #-, the counter proposal being to do everything
by means of eval time macros.

A common case wherein I used reader conditionalization while at MIT was
in the building and maintenance of several data files.  These files had
#+ and #- in them, and I wouldn't seriously contemplate writing a post
processor for all data read in, simply in order to avoid using #+.

One may argue that certain pieces of lisp programs that have reader
conditionalizations in them would have been in better style had they
used some eval time macro [no need to bring in the compiler here --
I assume that (cond (t ...)) would be optimized, but that doesn't
really matter].  On the other hand, in some cases, the #+ construct makes 
for much more succinct and readable code; compare a #+ in a bound
variable list with the eval-time macro that must construct up such
a defun in the absence of reader conditionals.

-- JonL --