Hi:

I have a need for a command that starts an isearch with a specific string
in the editable area that I can add and subtract characters from
interactively during the search.  I have things working with the following
code except the string does not appear in the editable area even though the
search is done for the fixed string.  Can anyone solve this?  I couldn't
get any of the isearch-yank-* commands to do the right thing here either.
Please help.  Thanks.

It would be much simpler if the user-level isearch commands like
isearch-forward could take a string/regexp as an argument and then jump
into the middle of a search as if the characters had been typed
interactively.  One might think setting isearch-string would do something
similar.

(defun isearch-for-string ()
  "Interactively search forward for next occurrence of a fixed string.
Then add characters to further narrow the search."
  (interactive)
  (let* ((match-str "fixed-string")
         (isearch-mode-hook
 (append '((lambda () (interactive) (setq isearch-string match-str))
   isearch-mode-hook))))
    (if (not (equal match-str (car search-ring)))
(isearch-update-ring match-str nil))
    (isearch-forward)))