CHAR

(CHAR <stirng> <index>)


The given index must be a non-negative integer less than the length of
string, which must be a string. The character at position index of the
string is returned as a character object (in Intelib Lisp, characters
are represented with strings of length 1).

NOTE unlike in Common Lisp, this version of CHAR function can't be 
used as the first argument to SETF.