Function: read-from-string

Read one Lisp expression which is represented as text by STRING.
Returns a cons: (OBJECT-READ . FINAL-STRING-INDEX).
FINAL-STRING-INDEX is an integer giving the position of the next
remaining character in STRING.
START and END optionally delimit a substring of STRING from which to read;
they default to 0 and (length STRING) respectively.

(fn STRING &optional START END)