[slim-vim] Patch for Vim FFI, searching

[Larry Clapp]

On Sun, Jun 18, 2006 at 08:34:15PM -0700, Brad Beveridge wrote:
> Hi all, my next post will add "package correctness" to Slim-vim, ie
> when you eval a form it will be evaluated in Swank in the correct
> package, but your Vim will need the following FFI patch.
[snip]
> (defun vim:search (pattern &key (back nil) (wrap t) (move-cursor nil))
>   (let ((flags (with-output-to-string (s)
>                  (when back (princ "b" s))
>                  (if wrap (princ "w" s) (princ "W" s))
>                  (unless move-cursor (princ "n" s)))))
>     (vim:funcall "search" (string pattern) (string flags))))

Vim's search(), by default, moves the cursor.  This one doesn't.

I would have said

  (defun vim:search (pattern &key (back nil) 
				  (wrap (plusp (vim:var "&wrapscan")))
				  (keep-cursor nil))
    (let ((flags (concatenate 'string
			      (if back "b" "")
			      (if wrap "w" "W")
			      (if keep-cursor "n" ""))))
      (vim:funcall "search" (string pattern) flags)))

but they both suffer from a minor annoyance: search() in Vim7 has 8
flags, which are all essentially booleans; having a keyword for each,
which is just T or NIL, seems excessive.  For example, we might end up
with

  (vim:search "pattern" 
    :back t :accept-match-at-cursor t :move-to-end t 
    :return-match-count t :set-tick-mark t :wrap t)

All the T's seem pretty redundant.  What do we think of just having a
list of flags:

  (vim:search 
    '(:back :accept-match-at-cursor :move-to-end :return-match-count
      :set-tick-mark :wrap))

We could even have a compiler macro that "compiles" a literal list of
keywords into a string at compile-time instead of run-time.  The above
would become:

  (vim:funcall "search" "bcepsw")

On the other hand, I guess we could always have both, and one would
call the other.  :)

Thoughts?

-- Larry