specification : identify : 由letter digit '_'(underscore)組成 key word : "globle" , "variables" , "prototypes" , "classes" , "classdef" , "class" ,"int" , "boolean", "string" , "true" , "false" , "unless" , "else" , "else" , "do" , "while", "print" , "return", "readInt" , "readString". Keywords and identifiers must be separated by white space or a token that is neither a keyword or an identifier. skip: " "(white space) ,"\t"(tab),"\n"(newline) operator : Binary : && , || , == , < , > , + , - , * , / , % . Unary operator : ! Other special characters: “{“, “}”, “(“, “)”, “[“, “]”, “;”, “,”, “.”, “=“ command : line comment // comment /**/ Unclosed comments are lexical errors String : "string"=>sequece of characters en...