+ ;; boundary for the purpose of syntax highlighting, so I stick
+ ;; the no-hyphens-or-underscores class on each end of the
+ ;; expressions.
+
+ (concat "\\("
+ (concat "\\(^\\<\\(" regexp "\\)\\>[^_-]\\)")
+ "\\|"
+ (concat "\\([^_-]\\<\\(" regexp "\\)\\>[^_-]\\)")
+ "\\)")