in clisp

1) Below is the parser written in class for the grammar 5 aA ;Ab5 : (setf program ']) (defun get-tk () (car program)) (defun accept-tk 0) (setf program (cdr program)) ) (defun 50 (if (null program) "Parsing successful" (if (eq (get-tk) 'a) (progn (accept-tk) (A)) "unexpected token" 1 (defun A0 (if (null program) "Program ended unexpectedly" (if (eq (get-tk) 'b) (progn (accept-tk) (S)) "unexpected token" 1 Modify the obeve.parser for the following grammar, and demonstrate using non-trivial strings thot the parser correctly porses yolifland invilid strings allowed by the grammar: 5bA1cAcSd Modify the obove parser for the following grammar, and demonstrate using non-trivial strings that the parser correctly parses valid and involidstrings allowed by the grammar: 5bAC ACSd Note A1: By correctly, it is meant as expected._ by flagging errors for invalid strings and displaying "success" for valid strings. Note a2 : By non-trivial string, it is meant a string other than a trivial string.. examples of trivial strings are "(c), '(b d), '0, and '(e). 1) Below is the parser written in class for the grammar 5 aA ;Ab5 : (setf program ']) (defun get-tk () (car program)) (defun accept-tk 0) (setf program (cdr program)) ) (defun 50 (if (null program) "Parsing successful" (if (eq (get-tk) 'a) (progn (accept-tk) (A)) "unexpected token" 1 (defun A0 (if (null program) "Program ended unexpectedly" (if (eq (get-tk) 'b) (progn (accept-tk) (S)) "unexpected token" 1 Modify the obeve.parser for the following grammar, and demonstrate using non-trivial strings thot the parser correctly porses yolifland invilid strings allowed by the grammar: 5bA1cAcSd Modify the obove parser for the following grammar, and demonstrate using non-trivial strings that the parser correctly parses valid and involidstrings allowed by the grammar: 5bAC ACSd Note A1: By correctly, it is meant as expected._ by flagging errors for invalid strings and displaying "success" for valid strings. Note a2 : By non-trivial string, it is meant a string other than a trivial string.. examples of trivial strings are "(c), '(b d), '0, and '(e)