lisp-slashify, prin1-to-string, and supported emacs versions

   From: Bob Rogers <[email protected]>
   Date: Mon, 16 Sep 2002 09:55:47 -0400

   . . .

      In fact, speaking of %s vs. %S, it occurs to me that lisp-slashify
   is entirely equivalent to the following . . . Perhaps lisp-slashify
   is a historical artifact, a product of older emacsen that didn't
   support %S?  Is it still desirable to support these older versions?
   If so, I probably shouldn't be using %S at all . . .

According to the first item in the "New Features for Printing And
Formatting Output" section of the etc/LNEWS file
(/usr/share/emacs/20.7/etc/LNEWS in my version of emacs), the %S
directive was added in emacs 19, but the next item implies that a
one-arg version of prin1-to-string was present in prior versions.
Because of that, I feel it is safe to commit the simplification to
lisp-slashify shown below, even though ilisp still claims to support
emacs 18.

   But I'm curious how important emacs 18 support really is, as that
determines how hard I have to work to avoid making use of nice features
like match-string and %S.  Does emacs 18 really work?  When was the last
time anybody tried to run ilisp under emacs 18?

					-- Bob Rogers
					   http://rgrjr.dyndns.org/

------------------------------------------------------------------------
Index: ilisp-utl.el
===================================================================
RCS file: /cvsroot/ilisp/ILISP/ilisp-utl.el,v
retrieving revision 1.2
diff -u -r1.2 ilisp-utl.el
--- ilisp-utl.el	12 May 2001 22:10:53 -0000	1.2
+++ ilisp-utl.el	21 Sep 2002 20:15:52 -0000
@@ -27,20 +27,16 @@
   "Put string in the *ilisp-send* buffer, backslashifying troublesome chars.
 I.e. put backslashes before quotes and backslashes and return the resulting
 string."
-  (save-excursion
-    (lisp-show-send string)
-    (set-buffer "*ilisp-send*")
-    (goto-char (point-min))
-    (while (search-forward "\\" nil t)
-      (delete-char -1)
-      (insert "\\\\"))
-    (goto-char (point-min))
-    (while (search-forward "\"" nil t)
-      (backward-char)
-      (insert ?\\)
-      (forward-char))
-    (buffer-substring (point-min) (point-max))))
-
+  ;; The quoting is now all done by prin1-to-string, since elisp and Common Lisp
+  ;; string quoting syntax is identical.
+  (or (stringp string)
+      (error "ilisp bug: argument to %s is %s, which is not a string."
+	     'lisp-slashify string))
+  (let* ((string (prin1-to-string string))
+	 ;; strip off surrounding quotes.
+	 (result (substring string 1 (1- (length string)))))
+    (lisp-show-send result)	;; for side effect.
+    result))
 
 ;;;%%String
 (defun lisp-prefix-p (s1 s2)


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