More on memq



On Mon, Apr 14, 2008 at 11:51 AM, Raymond Toy (RT/EUS)
<raymond.toy at ericsson.com> wrote:
>  I think I have used both m+ and add in various places in the code,
>  because that's what they were doing.  Is there a preference for one or
>  the other?  We could standardize on one, if, in fact, they are the same.

Well, I wrote the opers package N years ago, so naturally I prefer
add/mul/etc. On the other hand, I admit that (take '(%sin) ...) was a
failure of taste. One of these days, I'll rewrite it to also allow
(take'%sin ...).  What's more, the current version (== the 1975
version) calls the appropriate simplifier directly (e.g. simpsin),
which is incorrect since it bypasses the pattern-matcher:

  tellsimpafter(sin(xxx),23);
  sin(xxx) => 23
  :lisp (defun $test () (list '(mlist simp) (take '(%sin) '$xxx)
(simplifya '((%sin) $xxx) nil)))
  test() => [sin(xxx), 23]        <<< oops