(cl-ppcre:create-scanner regex &key case-insensitive-mode multi-line-mode
single-line-mode extended-mode destructive)
|Function: Accepts a regular expression - either as a parse-tree or as a string - and returns a scan closure which will scan strings for this regular expression and a list mapping registers to their names (NIL stands for unnamed ones). The "mode" keyboard arguments are equivalent to the imsx modifiers in Perl. If DESTRUCTIVE is not NIL, the function is allowed to destructively modify its first argument (but only if it's a parse tree).