How do I trim leading and trailing whitespace in Common Lisp?

Question

How do I trim leading and trailing whitespace in Common Lisp?

Answer 1

CL-USER> (string-trim 
      '(#\Space #\Newline #\Backspace #\Tab 
        #\Linefeed #\Page #\Return #\Rubout)
      "  A string   ")
"A string"

string-left-trim and string-right-trim for leading and trailing whitespace, respectively.