How to add list in file to Lisp -

i want add list in text file lisp , bound variable. example mylist.txt contains: ((1 2 3 4) (5 6 7 8) (9 10 11 12) (13 14 15 16) ) , want read file , and set list variable mylist.

    (defun readfile (filename) (let ((in (open filename :if-does-not-exist nil)))      (when in        (loop line = (read in nil)         while line (print line))        (close in)       )      ) )      (setf mylist (readfile "list.txt")) 

output should (mylist should bounded to): ((1 2 3 4) (5 6 7 8) (9 10 11 12) (13 14 15 16) )

i have seen of answer on stackflow regarding this, non them worked example tried reading line line , used collect dont seem give me right answer since collect's entire line , treat list item.

as stands far reading file , printing standard output ((print line) statement in readfile). instead, want collect input.

(defun read-file (file-name)   (let ((*read-eval* nil))    (with-open-file (in file-name)      (loop x = #1=(read-line in nil :eof) #1#         until (eq x :eof)         collect (read-from-string x))))) 

line-by-line: 1. please, use cl conventions names. 2. reading string/file dangerous in presence of read macros. setting *read-eval* nil prevents execution. 3. reading need simple. using with-open-file provides simple , safe interface (e.g. if condition (exception) raised, close file properly). in name of input stream associated file. 4. in loop @ each iteration read 1 line. here assume each line proper lisp expression (e.g., number or list). if have expression spanning multiple lines, needs changed. #1= lets remember form follows , #1# insert form. used avoid repetition of (read-line ...) form initial , then statements. read-line directed not throw error if end-of-file reached , return :eof instead. 5. until end-of-file reached... 6. read (convert string lisp data) , collect line read file.

this function returns list of (read lisp data) lines of file. example, if "text.txt" contains

((1 2 3) (4 5 6)) (a b c) (:f :g :h) 

the read-file of "test.txt" result in:

cl-user> (read-file "test.txt") (((1 2 3) (4 5 6)) (a b c) (:f :g :h)) 

finally, not use setf unless my-list defined using defvar or defparameter (in case should named *my-list*) or if defined locally using let.