Write a Lexer program in Java (LISPLexer.java) without using the Antlr4 system to generate the tokens for the LISP language. Write it as a class with a constructor and a lex() method so that the Parser program can use it. Here is a test program and a sample run:

public class TestLexer { public static void main(String args[]) { Lexer l = new Lexer(args[0]); Token t = l.lex(); while (t.getTokenID() != TokenTypes.EOF) t = l.lex(); } } mirage:3b raj$ java TestLexer "(+ (car (1 2 3 4)))" Next lexeme is LPAREN Next lexeme is ADD_OP Next lexeme is LPAREN Next lexeme is CAR Next lexeme is LPAREN Next lexeme is INT_LIT<1> Next lexeme is INT_LIT<2> Next lexeme is INT_LIT<3> Next lexeme is INT_LIT<4> Next lexeme is RPAREN Next lexeme is RPAREN Next lexeme is RPAREN Next lexeme is EOF