Incredible STRING band!

[JONL at MIT-MC (Jon L White)]

I've just installed a new STRING (and STRAUX) package, which
corrects a coulple of serious bugs, and utilizes the new
error checking facilities;  if "latent" features defelop,
there is a STRING.OFASL and STRAUX.OFASL on MC's LISP directory.
1) STRAUX makes certain that there are four functions
   +INTERNAL-CHAR-N, +INTERNAL-RPLACHAR-N, +INTERNAL-STRING-WORD-N,
   and +INTERNAL-SET-STRING-WORD-N.  These are non-checking versions,
   in in XLISP they are coded in the system in order to insure
   correct interruptibility.  This has made it possible to rewrite
   a lot of string functions which used to lambda-bind *RSET so as
   not to bind now.  (still, there are a few functions which will bind
   *RSET  to stop checking on sub-recursive calls -- primarily 
   STRING-SEARCH and STRING-APPEND).
2) The backwards versions of POSQ (like, STRING-BPOSQ-N) were buggy!
   This probably schrod a bunch of other backwards functions --
   like maybe backwards searching.  This is now fixed.
Hopefully, within a few days I'll have the new MACROEXPANDED scheme
in DEFMAX, and will build a new NILAID.  In the meantime, I'd
appreciate feedback from you regarding possible bugs mentioned in 2.