in reply to Re^2: Nifty qr OR bullets with butterfly wings
in thread un-Nifty qr OR ASCII bullet parser

It returns the string (?-xism:[@*+])

  1. qr/[%s]/ builds a regex that matches strings containing "%" or "s".
  2. sprintf stringifies the compiled regex to (?-xism:[%s]) to use it as the format pattern.
  3. The characters are included into the format pattern and the result is returned by sprintf.

So not only do you not end up with a compiled pattern, you waste time compiling a pattern you never use!