Protect against symbols with unsafe chars

Fixes abo-abo#648.

* lispy.el lispy--symbol-safe-chars-regexp: define safe chars.
(lispy--read): protect against unsafe chars in a symbol.

lispy.el

@@ -7286,6 +7286,12 @@ See https://clojure.org/guides/weird_characters#_character_literal.")
                      (match-string subexp)))
             t t nil subexp)))))
 
+(defconst lispy--symbol-safe-chars-regexp
+  (rx (any alnum ?+ ?- ?* ?/ ?: ?=))
+  "Regexp for \"safe\" characters.
+Safe characters are those which are suitable for a symbol and
+have no special reader syntax.")
+
 ;; TODO: Make the read test pass on string with semi-colon
 (defun lispy--read (str)
   "Read STR including comments and newlines."
@@ -7524,11 +7530,13 @@ See https://clojure.org/guides/weird_characters#_character_literal.")
                   (unless (lispy--in-string-or-comment-p)
                     (replace-match (format "(ly-raw racket-option %s)"
                                            (match-string 1)))))
-                ;; Clojure # in a symbol
+                ;; Protect symbols containing unsafe characters
                 (goto-char (point-min))
                 (while (re-search-forward "\\_<\\(?:\\sw\\|\\s_\\)+\\_>" nil t)
                   (unless (lispy--in-string-p)
-                    (when (cl-position ?# (match-string 0))
+                    (when (not (string-match-p
+                                lispy--symbol-safe-chars-regexp
+                                (match-string 0)))
                       (let* ((bnd (lispy--bounds-dwim))
                              (str (lispy--string-dwim bnd)))
                         (delete-region (car bnd) (cdr bnd))