正则表达式由一些普通字符和一些元字符（metacharacters）组成。普通字符包括大小写的字母和数字，而元字符则具有特殊的含义.本程序用于将式子翻译成正则表达式.-Regular expression by a number of common characters and some meta characters (metacharacters) component. Ordinary characters, including upper and lower case letters a